Fermilab Reports Dark Energy Not Needed

An anonymous reader writes "A Fermilab press release reports that the expansion of the universe may be explainable without the need for dark energy or a cosmological constant. Apparently, ripples from inflation in the early universe may account for the observed expansion rate of the universe."

Comments

fp

[Anonymous Coward]

fp

Nothing for you to see here.

[brilinux]

Nothing for you to see here. Please move along.

Well, apparently the dark matter is still important on Slashdot.

Re:Nothing for you to see here.

[digismack]

It doesn't matter.

Re:Nothing for you to see here.

[erice]

Nothing for you to see here. Please move along.

Wouldn't that be, nothing for you to *not* see here?

But what about the Horizon problem?

[mr100percent]

But what about the Horizon problem?

From an earlier /.-linked article 13 things that do not make sense:

The horizon problem

OUR universe appears to be unfathomably uniform. Look across space from one edge of the visible universe to the other, and you'll see that the microwave background radiation filling the cosmos is at the same temperature everywhere. That may not seem surprising until you consider that the two edges are nearly 28 billion light years apart and our universe is only 14 billion years old.

Nothing can travel faster than the speed of light, so there is no way heat radiation could have travelled between the two horizons to even out the hot and cold spots created in the big bang and leave the thermal equilibrium we see now.

This "horizon problem" is a big headache for cosmologists, so big that they have come up with some pretty wild solutions. "Inflation", for example.

You can solve the horizon problem by having the universe expand ultra-fast for a time, just after the big bang, blowing up by a factor of 1050 in 10-33 seconds. But is that just wishful thinking? "Inflation would be an explanation if it occurred," says University of Cambridge astronomer Martin Rees. The trouble is that no one knows what could have made that happen.

So, in effect, inflation solves one mystery only to invoke another. A variation in the speed of light could also solve the horizon problem - but this too is impotent in the face of the question "why?" In scientific terms, the uniform temperature of the background radiation remains an anomaly.

"A variation in the speed of light could solve the problem, but this too is impotent in the face of the question 'why?'"

Also, in the same article, Dark Energy is discussed:

9 Dark energy

IT IS one of the most famous, and most embarrassing, problems in physics. In 1998, astronomers discovered that the universe is expanding at ever faster speeds. It's an effect still searching for a cause - until then, everyone thought the universe's expansion was slowing down after the big bang. "Theorists are still floundering around, looking for a sensible explanation," says cosmologist Katherine Freese of the University of Michigan, Ann Arbor. "We're all hoping that upcoming observations of supernovae, of clusters of galaxies and so on will give us more clues."

One suggestion is that some property of empty space is responsible - cosmologists call it dark energy. But all attempts to pin it down have fallen woefully short. It's also possible that Einstein's theory of general relativity may need to be tweaked when applied to the very largest scales of the universe. "The field is still wide open," Freese says.

Re:But what about the Horizon problem?

[Anonymous Coward]

If the universe is 14 billion years old, and the edges are nearly 28 billion light years apart, what's the problem? It expands at relativistic speeds 14 billion years one way, 14 billion years the other. 14*2 = 28. So unless they're stating this wrong, shouldn't that be the way that it works?

Re:But what about the Horizon problem?

[PureFiction]

If you read the article you would see they address this issue. The key is to realize that the horizon extends beyond what we can see (our cosmic horizon):

• It is widely believed that during the inflationary expansion early in the history of the universe, very tiny ripples in spacetime were generated, as predicted by Einstein's theory of General Relativity. These ripples were stretched by the expansion of the universe and extend today far beyond our cosmic horizon, that is over a region much bigger than the observable universe, a distance of about 15 billion light years. In their current paper, the authors propose that it is the evolution of these cosmic ripples that increases the observed expansion of the universe and accounts for its acceleration.
• 
  
  "We realized that you simply need to add this new key ingredient, the ripples of spacetime generated during the epoch of inflation, to Einstein's General Relativity to explain why the universe is accelerating today," Riotto says. "It seems that the solution to the puzzle of acceleration involves the universe beyond our cosmic horizon. No mysterious dark energy is required."

Re:But what about the Horizon problem?

[Penguinoflight]

I was going to moderate your comment "interesting", but then I realized all of this is just hypothesis so it doesn't really belong outside the original study group.

two edges are nearly 28 billion light years apart and our universe is only 14 billion years old.

In 1998, astronomers discovered that the universe is expanding at ever faster speeds. It's an effect still searching for a cause - until then, everyone thought the universe's expansion was slowing down after the big bang.

A true scientific perspective would be to look at the evidence of the universe and theorize about the origins from there. Many studies(like this one find that light slows down over time. The idea that the universe must be 14-28 billion years old just to cover for the huge size is unnecessary and sloppy when the speed of light is not considered as a constant.

I beileve in explaining things in the most simple possible way. If a theory is challenged by plain old evidence the theory probably has an error and should be fixed. Making up new theories to explain a dead one is very sloppy and it takes away from the ethical reputation of science.

Re:But what about the Horizon problem?

[Anonymous Coward]

But what about the Horizon problem?

American wastelines acutally have little to do with particle physics, usually it's down to McDonalds, Burger King, and fried chicken.

Re:But what about the Horizon problem?

[bperkins]

But what about the Horizon problem?

The work in this article assumes that inflation is right. People don't like inflation because they don't know how it happend, but something like it had to have happened in the early universe.

Re:But what about the Horizon problem?

[LiquidMind]

From TFA: "These ripples were stretched by the expansion of the universe and extend today far beyond our cosmic horizon, that is over a region much bigger than the observable universe, a distance of about 15 billion light years..."

i'm not much of an astronomer, but am i right to understand that (theoratically) our cosmic horizon expands at the speed of light? ie, does it gain ~300,000,000 m/s?

Re:But what about the Horizon problem?

[Ramze]

I think it's because for it to be that big, all matter and energy in the universe would have to have exceeded the speed of light to be where it is today or at least be moving at the speed of light away from the epicenter. Also, it doesn't account for the time needed for the universe's background radiation to become uniform (even out over time)

Re:But what about the Horizon problem?

[pintpusher]

Many studies(like this one find that light slows down over time.

seems in that article they still like E=MC^2

so does this mean that the totally energy of the universe is decreasing? or is total mass increasing to make E a constant?

but then...

on another note: does this mean that our quest for speed-of-light travel should focus on waiting for C to approach 70 MPH?

Re:But what about the Horizon problem?

[rm999]

According to a recent scientific american article that was written to debunk common myths about the universe, given that the universe is expanding, the visible universe is actually larger than 14 billion ly radius. This is because light from a star that is *now* 30 billion ly away could have reached us by now because for part of its trip it was closer than 30 billion lys from us. This is, of course, assuming that light goes at a constant speed.

The problem with all this highly theoretical physics is that no one really understands it - even the people who study it. I don't study it; I am just repeating what I read in an article, so I am sure that I know even less about all this stuff.

Re:But what about the Horizon problem?

[farquharsoncraig]

IT IS one of the most famous, and most embarrassing, problems in physics.

Obviously a physicist didn't write this article. When something unexpected happens in the field of physics, physicists are not embarassed, there is rather much rejoicing among the people of science. The TOE aside, we in the pursuit of pure research do not concern ourselves with the prerogative of questions or the solving of problems, rather we are in the business of finding new questions and new classes of questions to ask. This is the essential difference between pure and applied research.

Re:But what about the Horizon problem?

[Anonymous Coward]

No, because then we would never get anywhere, even here on earth. We want the speed of light to increase, not decrease.

Re:But what about the Horizon problem?

[digitalchinky]

This is all theory, but say you could instantly travel 14 billion light years to the horizon (as seen from earth)

What would you see? Another horizon a further 14 billion light years distant? My personal feeling is yes, and that the age of the universe is wrong - I don't subscribe to the big bang theory, relativity, or any other convenient explanations for this 'anomaly'. Nor do I believe in God.

I may be marked as troll, but I suspect there are many others with a similar view.

Re:But what about the Horizon problem?

[niktemadur]

While it is a generally accepted law that nothing WITHIN space can travel faster than light, this law may not apply to SPACE ITSELF, which could inflate at superluminous speeds if the correct conditions are present.

I know this sounds bizarre, and I'm no expert on the subject, but I'll try to give a simple example that even I can understand:

Let's say space is like a balloon.
Matter are the molecules within that balloon.
The matter within may not move faster than light by its' own means.
But the balloon may inflate faster than light, and the matter within goes along for the ride.
At the end of inflation, the matter has kept its' same relative position in space.

The correct condition for inflation to happen is known as supercooling. Here is an example that Alan Guth used to describe it: water that's below 32 degrees farenheit but retains its' liquid state. However, just gently tap the plastic mold and the water will abruptly crystalize into ice before your very eyes. Supercooled water.

Another example would be a beer in the freezer that's liquid, but turns to ice from the top down when you open the lid. Supercooled beer.

Accordingly, the universe would have to inflate at a certain speed (much faster than light) to re-attain its' appropriate state under specific conditions.

According to Alan Guth, most of the universe's matter cancelled itself out instants after the Big Bang, due to matter-antimatter collitions. In a super-excited state, the universe found itself almost empty, and had to readjust by inflation and a spontaneous burst of creation of matter. In fact, Guth said that with 28 pounds of matter under the right conditions, a universe just as massive as ours could be created. This is why Guth said that our universe could be the ultimate "free lunch".

Re:But what about the Horizon problem?

[bytesmythe]

Yes, there are.

Re:But what about the Horizon problem?

[Y2]

But what about the Horizon problem?

Inflation solves the horizon problem. According to this latest calculation (see TFA), inflation also leaves some UBLW (unimaginably long wavlength) gravitational waves that account for the apparent acceleration of the general expansion, without the shamefully ad-hoc introduction of dark energy.

Re:But what about the Horizon problem?

[Anonymous Coward]

Yes, you'd see another horizon, of the same size. (Although the cosmological horizon is not 14 billion years distant; due to the expansion of space, the distance today to a point in space where light in the past was emitted, but is not yet visible, is not equal to the age of the universe.) This doesn't invalidate the age of the universe, and is in fact a prediction of inflationary Big Bang cosmology.

Re:But what about the Horizon problem?

[John Hasler]

> ...moving at the speed of light away from the
> epicenter.

There is no epicenter.

Re:But what about the Horizon problem?

[dahlek]

I thought the "uniform" issue was solved, when they did a more detailed scan of the background radiation?

I thought that both a scientist who concentrated just on a tiny spot of the sky, and a newer probe launched by NASA both reached the same conclusion - that the early universe was in fact lumpy as expected?

Re:But what about the Horizon problem?

[Anonymous Coward]

The universe is very uniform on average, which needs to be explained (deviations from average uniformity get amplified under non-accelerating expansion). Locally, there are non-uniformities in the density distribution. Inflation explains both the average flatness and the local perturbations.

Re:But what about the Horizon problem?

[Anonymous Coward]

Suppose, just suppose, that the center of our cosmos was not the absolute center of all creation. Suppose that the universe is not rushing toward empty space but is, in fact, being pulled toward something even larger.

That would account for the acceleration, now wouldn't it?

Re:But what about the Horizon problem?

[Penguinoflight]

does this mean that our quest for speed-of-light travel should focus on waiting for C to approach 70 MPH?

I hope not. Perhaps the most exciting idea that could come out of this discovery is that the speed of light is not an upper bound on possible travel speed.

With little formal physics understanding we know that everything is less complex to calculate when an object is moving less than 1/10 C. Otherwise the rules are more complex. I'd guess things just get insane when studying speeds above 1C.

Re:But what about the Horizon problem?

[sconeu]

I always thought that the "Ultimate 'free lunch'" comments had to do with the fact that the universe might be a zero-point fluctuation that got waaaaay out of hand.

Re:But what about the Horizon problem?

[Almost-Retired]

You can solve the horizon problem by having the universe expand ultra-fast for a time, just after the big bang, blowing up by a factor of 1050 in 10-33 seconds. But is that just wishful thinking? "Inflation would be an explanation if it occurred," says University of Cambridge astronomer Martin Rees. The trouble is that no one knows what could have made that happen.

Unforch, either the exponent was forgotten, or got lost in an html glitch someplace, What I'm refering to is the 1050 figure used above, which should be 10^50, which is the correct value used in Martin Rees's original release on the subject.

And that is not a trivial difference folks, it is truely astronomical in its own right.

--
Cheers, Gene
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
99.34% setiathome rank, not too shabby for a WV hillbilly

Re:But what about the Horizon problem?

[Planesdragon]

If the universe is 14 billion years old, and the edges are nearly 28 billion light years apart

It's not.

Our perceptable universe is 28 billion light-years apart. We have no way of knowing how much larger the universe is, because no information from beyond our information-cone can get to us.

(Graph space and time on an X-Y axis. Pick a point on Y, time, and draw two 45-degree lines down the page. As time progesses, the distance that we can get light from increases, because light has a finite speed. That "cone" of sense is what I mean by information-cone.)

Re:But what about the Horizon problem?

[Anonymous Coward]

Bender: Like putting too much air in a balloon.

Fry: Of course!

Re:But what about the Horizon problem?

[Artifakt]

At the risk of over-simplifying:
Look one way, there's a certain amount of lumpyness. Look the opposite way, there's the same amount of lumpyness - that's uniform - uniformly lumpy.
Finding early lumpyness helps explain why the modern universe is very lumpy with galaxies and groups of galaxies and voids between them. The more detailed scan really didn't find as much lumpy as expected, but it found enough lumpyness that Cosmologists are thinking it just might explain modern structure, or at least it's not off by too tremendous a factor.
The uniformity problem is different. Look one way (call it towards point A), see 12 billion light years. Look the opposite (towards point B), see 12 billion more. 12+12 is 24, so that spot on the far left has never exchanged information with the spot on the far right since the universe began. (Light from point A is only half way to point B, and vice versa). If they haven't exchanged information, how can they be in sync? To some theoreticians, that's like having a bunch of dancers staying in step, when some of them are so far from the band that the sound of the beat hasn't reached them yet.

Re:But what about the Horizon problem?

[WaterBreath]

A few things:

According to "accepted" theories of expansion, there is no epicenter. All space is expanding equally in all directions. So wherever you are standing, everything will appear to expand outward away from you.

Because of that, things farther away from you will be receeding from you faster, because every extra bit of space between you and them means an extra bit of expansion, and so an extra bit of recession speed. As the theory goes, superluminal recession speeds are possible because the distant objects are not actually moving relative to the stationary frame of space in their vivinity. Space itself is changing shape, and the "motion" we see is just a side-effect.

Supposedly, there is a certain distance, which can be measured starting at any given point, beyond which every everything is receeding from the reference point faster than light, and so will never be visible from that point. This is called the Hubble distance. Related is the Hubble constant, which is a measurement of change in velocity of expansion per unit distance from the reference point. (Not the odd way to measure acceleration. Normal acceleration is m/s/s, or m/s^2, but this is m/s/m, or just 1/s, which is 1Hz. Weird, eh?) The Hubble constant is under contention, I think, and the value of the Hubble distance depends on the value of the constant.

Anyway, this stuff is kind of where the idea of Star Trek's "warp drive" comes from (at least in the more recent series). If it were possible to create some sort of device that could cause the space in front of a ship to contract and the space behind to expand proportionally, the ship could move without moving through space. It would be space itself changing shape around the ship that causes it to "move". And hence the speed at which you could move would be limited only by the speed at which you could channel energy into the expansion and contraction of space. Of course, this might just happen to be limited by the speed of light as well, so maybe superluminal speed still wouldn't be possible!

But if these guys' new idea is right, then none of that matters. =)

Re: But what about the Horizon problem?

[Black Parrot]

> I don't subscribe to the big bang theory, relativity, or any other convenient explanations for this 'anomaly'.

Are you saying you reject GR? If so, why?

Re:But what about the Horizon problem?

[ikkonoishi]

The beer isn't actually supercooled.

When you open the top the carbon dioxide escaping actually lowers the temperature.

Re:But what about the Horizon problem?

[Surazal]

The problem with the theory wasn't so much you couldn't move faster than the speed of light (apparently this was a valid way to "cheat" according to the calculations). It was that the amount of energy required to maintain such a bubble would be powerful enough to instantly destroy any event causing this phenomenon in the first place (aka a warp drive). It was akin to being inside a extremely unstable black hole.

Re:But what about the Horizon problem?

[MillionthMonkey]

There is no epicenter like there is in an earthquake, but you can define any position at rest in the frame of the background radiation itself to be as good of an "epicenter" as any other for purposes of this discussion. The Earth doesn't meet this standard, because it's moving at a speed of 365 km/sec relative to the CMBR (hence the Doppler shift), but it probably doesn't matter.

Here is a good FAQ entry regarding the difference between the observable universe and the entire universe.

Re: But what about the Horizon problem?

[digitalchinky]

http://members.aol.com/crebigsol/awards.htm

Re:But what about the Horizon problem?

[jeffybob]

im new at all of this, but is it possible that some thin layer of dense matter is expanding from the big bang and is stretching space out? Dont laugh at me for my lack of experience here....

Re:But what about the Horizon problem?

[IamNotWitchboy]

Not likely. Suppose an ultramassive 'something' is pulling the whole universe in one direction, if that was the case, the background radiation would be stronger on the opposite side of the attracting object and the acceleration of galaxies and other objects in our visible universe would have the same direction.

As has been mentioned, the background radiation is the same no matter where you look at, and the doppler shift of the big majority of galaxies shows that almost every single one is moving away from us.

Re:But what about the Horizon problem?

[WhatsAProGingrass]

I don't know much about light. But I did read somewhere that a pulse of light can only travel at the speed of light, however, whats contained withing that pulse can travel faster than light, as long as it stays withing the pulse. Kind of like, if you were in the bed of a truck and ran foward while the truck was traveling, you would be going faster than the truck, but from the perspective of the whole truck and everything in it, you are all going the trucks speed. What if the universe is just stuck in a truck.

Re: But what about the Horizon problem?

[Anonymous Coward]

This person has $50k to award to anyone who can defend GR.

YET, they can't afford to have this site hosted by anyone other than aol.com AND can't afford a web designer to design a site with decent html. I smell bullshit.

Let me explain: it's not that GR is undefendable, it's just that nobody has bothered to take this amateur site seriously enough to bother defending this sites accusations.

Oh, and one more thing: All present theories combined cannot explain every known phenomenon in the universe, thus they are all wrong to some degree. Saying GR is wrong is just like saying Newton was wrong. They aren't "wrong", per se, but they are accurate approximations. In science, there are no universal truths, only approximate theories that are backed up to some degree by circumstantial evidence. As more evidence comes to light, the theories are modified accordingly.

It's been known, even by Einstein, that GR does break down in certain circumstances. Within an atom, for example. Einstien himself would admit that GR is "wrong" within the confines of an atom.

Point being, if you want to delude yourself into believing that there is such a thing as "truth", go become a born again Christian. If not, then regard all present theories as what they really are, incomplete approximations.

Re:But what about the Horizon problem?

[Anonymous Coward]

You can understand the ever increasing speed of expansion if you stop thinking on such a small scale as the universe. Think of the big bang as a balloon that started out small but the force of the explosion is inflating the balloon. What we think of as our universe is actually on the edge of that balloon. As the balloon continues to inflate, the points that we consider as opposite ends of the universe are really just like 2 points on the surface of that balloon. And as you know, if you were to draw 2 dots on the outside of a balloon and then start blowing up the balloon, the 2 dots would get farther and farther from each other at an ever increasing rate.

Re:But what about the Horizon problem?

[hcjiv]

Suppose I draw two dots on a balloon to mark the positions of your molecules and then add tick marks between them at every inch to measure the distance. Now you inflate the balloon and we count the tick marks to see how far apart the molecules are now. Amazingly we find they are the same distance apart!

Now I am no expert on general relativity so I am certain I am wrong, but if it is space itself that is expanding why wouldn't the distances measured within that space still be the same?

Thanks,
-Harry

Re: But what about the Horizon problem?

[Darby]

A brief perusal of the first "paper" linked there shows that he is stating that both 'v' and 'c' are constants in the Lorentz transforms in some places and then using that to come to some sort of result that doesn't really follow clearly, or at least there is a lot of hand waving.

'c', the speed of light is a constant. 'v' is the velocity of what you're looking at which is a variable.

Although, I do have to give him credit for some pretty amusing ways of wording things:

'Any nonzero value of speed found in the Lorentzian equations in Eq. set A, such as v=0.2c, for example, must now be ridiculed'

I would have loved to have used that on some of my math exams in college.

"Since R is a Euclidian space and we have demonstrated that the set A in R is both closed and bounded we know by the Heine-Borel theorem that it is compact and hence can be ridiculed."

Re: But what about the Horizon problem?

[Anonymous Coward]

Cameron Rebigsol is one of the most well-known cranks on the sci.physics Usenet groups. (Or rather he was, he dropped off a few years ago.) He has no understanding whatsoever of even simple mathematics or relativity, and if you find his arguments convincing, neither do you. I once had a discussion with him about his incorrect calculation of the circumference/diameter ratio in general relativity (his paradox one), which quicky demonstrated his inability to comprehend length contraction.

Re:But what about the Horizon problem?

[selectspec]

Negative Higgs field solves the horizon problem. Toss in a little spacetime rippling and Negative Higgs can produce the current expansion (inflation) that we observe today.

Re:But what about the Horizon problem?

[Anonymous Coward]

You mean, why isn't the expansion unmeasurable because our measuring sticks are expanding with space? See this FAQ.

Re:But what about the Horizon problem?

[hesiod]

If the "edge" looks 14 billion light years away from the "center," wouldn't the whole kit n' kaboodle be 56 ly across?

If it looks 14b ly away on one side, that light left that point (14b L-Y away) 14b years ago and has had another 14b years to continue expanding out. Assuming constant speed (not a safe assumption at all), it would be twice as far as it looks. 28b ly that way, 28b the other.

Maybe I don't know what I'm talking about. Probably.

Re:But what about the Horizon problem?

[rm999]

Yes, I believe that is mostly correct according to current accepted theory.

Re:But what about the Horizon problem?

[dahlek]

I see. Is information transfer required? I mean, the speed of light is a law within our universe - maybe this doesn't apply to the universe itself in terms of it's role in a greater meta-verse of some kind?

Not to jump into philosophy-lala land here, but if things like time, speed, "direction", etc., are properties of our universe, maybe they don't mean anything outside of our universe (if there is such a region)? So, perhaps the expansion of of space itself, not matter or energy, but the space that matter and energy occupy, can expand faster than light. If we allow for this, then maybe the laws that govern matter and the layout of the galaxy chains, etc., were laid out when all matter was in close range - the dancers were each given nstructions at dance-practice, and then sent their own way.

Re:But what about the Horizon problem?

[Retric]

IANAP but it alwase seemed to me that if space where expanding at a nearly constant rate then let's say you start out with 10 points 1,2,3,4,5,6,7,8,9,10 on a line and each point is moving away from the points next to it at say 1/3c then if your sanding on point 1 you can see point's 2, 3 and 4 but never 5 however you could move from point 1 to point 2. Now at point 2 you could see point's 1,2,3,4,5 but nothing past 5. So by moving from one to 2 then 3, and reaching 4 you can then reach point 5.
-JMK

Re:But what about the Horizon problem?

[Anonymous Coward]

The constant-speed assumption is indeed wrong, so the size of the universe doesn't bear a linear relation to its age.

Re:But what about the Horizon problem?

[dillon_rinker]

The speed of light is constant. If you build a ruler that's 186 miles long, you will find that light takes .001 seconds to traverse it. Suppose that space expands by 1%. Your ruler is now 187.86 miles long, but you can't tell by measuring it with itself. Yet light will now take .00101 seconds to traverse the ruler.

By analogy, on your balloon, your ruler has inflated along with space, but it will now take a ladybug twice as long to walk from point A to point B.

I am no expert, either, and I don't know if what I say is true, but I do think it's possible for your analogy to be flawed.

Re:But what about the Horizon problem?

[Alsee]

That is an extremely common misunderstanding of the big bang. The Big Bang was no ordinary "explosion", and it had no center, no edge. At least no center in our universe.

The best way to explain it is to imagine we are all ants living on the surface of a gigantic balloon. Imagine that for us there was no "up" or "down". We just live on the two-dimensional surface of the balloon. The balloon is our universe. There is nothing inside the balloon, or if there is it's not part of our universe and we don't know anything about it. There is nothing outside the balloon, or if there is it's not part of our universe and we know nothing about it.

Then we realize that the balloon is being "inflated", it is expanding. All of the stars on the surface of the ballon are getting carried apart. The space between them - the rubber - is stretching. There is no edge. There is no center, at least no center anywhere on the balloon.

Then imagine going back in time. The balloon is shrinking, deflating. Everything on the balloon is getting closer together. All the stars on the balloon get closer together. The space between them - the sheet of rubber - is contracting. If you keep running it backwards the gigantic balloon shrinks down to a ping-pong ball, but you have everything in the universe squished down onto the surface of the ping-pong ball. Everything is squished down far denser than the core of a star. Even denser than a black hole. And it is incredibly hot, unimaginably hotter than the core of a star. And you keep shrinking it down to a tiny dot. That tiny dot is the start of the big bang. The big bang is the skin of that expanding balloon. The balloon has no edge, no fast stuff exploding away at the outside, no center with stuff sitting still. An expanding universe with no edge, and not expanding into empty space. All of space is the skin of the balloon itself.

To the extent that the big bang has any "center", it was that tiny dot in the past.

The big bang was an explosion of space itself.

-

Re:But what about the Horizon problem?

[Alsee]

What would you see? Another horizon a further 14 billion light years distant?

Correct. It is almost exactly the same as how you can see a horizon 25 miles away on earth. If you could instantly travel 25 miles to that horizon then you would still see a horizon 25 miles away. You can do that over and over and you'll never get to an edge. THERE IS NO EDGE. If you do it enough times we suspect you may eventually get back to where you started from. Just as you'll get back to where you started if you do about a thousand 25-mile jumps here on earth.

-

Re:But what about the Horizon problem?

[hcjiv]

If you are right then the speed of light would change as the universe expands. Today I measure the distance between two objects with my 186 mile ruler. Then measure the time it takes light to get from one to the other. I get 0.001 seconds. Tomorrow I again measure the distance with the same ruler. It still says they are 186 miles apart since the ruler has expanded as well but now the light takes 0.00101 seconds to get there. As an observer I must conclude that the speed of light has changed. The real question I have is if space itself is expanding why do the distances between objects change? Do objects also expand or only the 'empty' spaces between them?

BTW, the ladybug is not really a two dimensional creature living within the geometry of the surface of the balloon.

Re:But what about the Horizon problem?

[WaterBreath]

You're missing two things:
1) Moving from one point to another takes time. You can do it, at most, as fast as light does.
2) Point 5 is not stationary during your traversal of this space.

At the beginning of your example, point 5 is receeding from point 1 at 5/3c. If you move from point 1 to 2, you will be moving at most a little less than 3/3c. Which means point 5 is moving, during that time, 2/3c faster than you are. Which means that by the time you get to point 2, point 5 will actually be even farther away from point 2 than it was from point 1 when you left.

Compounding the problem even further is the fact that point 2 is moving away from point 1 at 1/3c even while you are moving toward it. So if you move at 3/3c from point 1, you are still only moving at 2/3c toward point 2. Even if this makes sense to you, a lot of people still have a big problem with the fact that things are "moving" faster than c. But if you can wrap your head around it, remember that it is spacetime that is expanding and changing shape, not the object that is actually moving.

Re:But what about the Horizon problem?

[Anonymous Coward]

So you're saying there was some sort of space or universe matter present before the Big Bang?

Re:But what about the Horizon problem?

[spike hay]

28 billion LY is the diameter of the observable universe. But the universe is actually many, many times that size. Space itself, not matter, is expanding. If you graph recessional velocities of other galaxies versus their distance, you will see a very linear scatterplot showing that distant galaxies receed faster than closer ones.

Space is expanding by about 75 kilometers per second per megaparsec (give or take quite a bit. This means that much of the universe is not visible to us, as it is effectively expanding at superluminal velocies. By cancelling out units, we can get what is called the Hubble constant in inverse seconds. By taking the inverse of that, we get the age of the universe. If we assume 75 km/s, we get a value of about 13.25 billion years, if I remember correctly.

The age of the universe is the amount of time it took for those galaxies to move from the center of the universe, in our case, Earth, to their present locations.

Re:But what about the Horizon problem?

[Retric]

Your still missing my point take those same points.

A, B, C, D, E ...

If you standing at A then B is moving at 1/3c away from you C is moving 2/3c and D is moving 3/3c and E is moving 4/3c.

But by moving to point B: then B is moving at 0/3c away from you C is moving 1/3 C and D is moving 2/3c and E is moving 4/3c.

Yes it takes time to move from one point to the other but unless the rate of expantion is increasing you should be able to get there. Now if your saying point's by the time you get to point B then point C will be going 2/3c from point B and 4/3c from point A that's one thing but I have not read that the rate of expantion is increasing.

Re:But what about the Horizon problem?

[Artifakt]

There's some proofs that information transfer is required, but they are all pretty limited as physicists see them, and abstract mathematicians see bigger gaps in these theories. For example, Dr. Hawking gave some arguements for instantanious transfer in his popularization, A Brief History of Time, but he also switched the way he was using the word imaginary, sometimes sticking to the math definition as in imaginary numbers, sometimes letting that slip a bit towards the popular meaning of the word.
One interpretation of Quantum Mechanics claims that particles that have been in close proximity remain coupled by some sort of instantanious (FTL) means of knowing each other's states. If someone rigorously proves that instantanious information transfer is absolutely required, that's likely to also extend to a proof that this quantum mechanic interpretation is preferred over the others, which would be a definite huge step forward in physics. Right now, that's not the standard model, at least yet.

Re:But what about the Horizon problem?

[Anonymous Coward]

Quantum entanglement is often proposed to explain the black hole information loss paradox. However, this does not entail "information transfer"; entanglement does not allow you to transmit information FTL (with a black hole or not).

Re:But what about the Horizon problem?

[WaterBreath]

But by moving to point B: then B is moving at 0/3c away from you C is moving 1/3 C and D is moving 2/3c and E is moving 4/3c.

Yes, but even if you move at c, E will still be moving away from you at an additional 1/3c. You've reached your maximum speed, but E is still speeding away. No matter how long you chase it, E will be moving faster than you, and increasing its distance from you. So you can't just jump the gap from one point to another and suddenly have E be moving less than "c".

Hence anything that is already receeding faster than light, you can never catch up with. Since you are limited to c yourself and it is not, it will always be moving away, and as I'll note below, accelerating away.

Yes it takes time to move from one point to the other but unless the rate of expantion is increasing you should be able to get there.

Expansion itself does not increase. But the recession speed of an object does increase. Not with time directly, but with distance. Each "new" bit of space that arises from expansion also expands itself. (It's cyclic: expansion fuels itself.) And since something moving away from you is increasing its distance with time, the "total expansion" between two objects does therefore also accelerate indirectly with time. So anything that has a recession velocity relative to you is not only moving away from you, but accelerating away from you.

You can "catch" point C, by moving toward it faster than it is moving away from you. But you can't go faster than E, so it will always be increasing its distance, and so it's speed.

Due to this acceleration, things that are now within reach may not always be, if you wait too long to set out for them. As soon as they cross the threshhold of "c", they're beyond reach.

And finally...

Yes it takes time to move from one point to the other but unless the rate of expantion is increasing you should be able to get there. Now if your saying point's by the time you get to point B then point C will be going 2/3c from point B and 4/3c from point A that's one thing

Given what I've stated above, either of those situations are possible. It depends solely on your speed, and the distances between the points in question. The fact that you are closing the gap between you and point B does not necessarily mean you are closing the gap between you and point C, because C is inherently moving away faster than B is, and accelerating faster as well.

Within the assumptions of relativity, the only thing that would call all this into question is this: Since recession due to expansion isn't the same type of motion as what you experience when you travel from A to C, it may be possible that the "length contraction" you perceive in your surroudings may result in the recession speed of E "magically" being decreased to below "c". I'm not sure how all that evens out. I'm not actually a physicist, just someone who reads quite a lot about physics.

Anyway, all this is only visible over very large distances, on the scale of many parsecs. And it all hinges on two assumptions: 1) Space itself is indeed expanding at a universal rate per (for example) parsec. 2) We are indeed limited by the "c" speed limit.

Re:But what about the Horizon problem?

[Retric]

If "Space itself is indeed expanding at a universal rate per (for example) parsec." then I would have to agree with you. I had thought that space was expanding at a fixed rate relitive to exiting object's / locations not distance.

I guess that means that at some point we would be unable to travel to anything else in the "local group" o well it's been a while sence I looked into this stuff. Anyway, thanks for the info.

Re: But what about the Horizon problem?

[joelt49]

Hmm, I could propose this to a Nobel Laureate who got the prize for giving the first indirect evidence of gravity waves, but he probably doesn't need the money. He's also the one who taught me Special Relativity. That being said, just looking at the proof is riddiculous. The x=ct and x'=ct' is absurd and completely unjustified. It's only true in a special case, when v=c. When v=c, you get all kinds of wierd and funny things. Anyway, that's all the time I had to glance over it. If he could legitimely disprove GR, he'd definitely get a Nobel.

So basically

[Neil Blender]

They don't need somethings they invented to explain away what they didn't understand.

Re:So basically

[theparanoidcynic]

Go science! Now if only religion could get around to realizing that . . . . . .

Re:So basically

[Anonymous Coward]

Go science! Now if only religion could get around to realizing that . . . . . .

Heh, I had almost that exact same sentence in my post but I had second thoughts.

NB

Re:So basically

[Anonymous Coward]

When you have karma shields as tough as mine it makes you a bit fearless about trolling. ;) TPC

Re:So basically

[jaavaaguru]

Its only a matter of time before US ISPs are required to filter news like this...

Re:So basically

[theparanoidcynic]

News? I'm not news. I'm just a comical little troll for the forces of rational cynicism. (The only job left to me now that the chances of seeing Secular Humanism in the US during my lifetime appear to be nil.)

Re:So basically

[Anonymous Coward]

[T]he chances of seeing Secular Humanism in the US during my lifetime appear to be nil.

Thank God! :-)

Re:So basically

[Jesus_666]

In related news, the Vatican has just announced that they have found a reason as to why God has been suspiciously silent in the last centuries. "You see," explains J. Random Cardinal, leader of the Vatican's R&D team, "when God created the universe there was this expansion thing going on, during which the universe expanded by a factor af about 1000 in less than a minute. Additionally, ripples in spacetime were created, which have grown in size and now are giant waves travelling at the speed of light. We have just received a postcard from God saying that He's gone surfing but will be back in a millennium or two."
When asked if it wasn't a bit uncaring for God to ignore Earth for so long, Cardinal answered: "Hey, sometimes everyone needs a vacation. Speaking of which, I'm off to Hawaii."

DUH.

[Anonymous Coward]

DUH.

Difference?

[Ender_Wiggin]

Can someone tell me, what's the difference between Dark Matter and Dark Energy?

Re:Difference?

[Narchie Troll]

E=mc^2

Re:Difference?

[Fox_1]

no difference, matter and energy are the same (not trek science either) - just a matter of velocity or something.

Re:Difference?

[Jamu]

The same as the difference between normal matter and energy except these forms would emit no visible light (and are thus dark).

Re:Difference?

[fredrikj]

Dark matter would include coal, for example. Or the night sky. Dark energy - forces of evil such as fear, hate, etc.

Re:Difference?

[zarathustra_slayer]

Dark matter is postulated to account for the excessive gravity observered in galaxies (by lensing effects and velocity distributions). Like normal matter, it clumps under the effects of gravity.

Dark Energy is a uniform energy density at all points in space. It has a negative pressure and thus can explain why the universe is expanding at an increasing rate.

Re:Difference?

[Pfhorrest]

The other responses to this thus far are completely off. Dark matter and dark energy are not (by any current theory at least) related anything like how normal matter and energy relate via e=mc^2.

Dark Matter is a hypothetical unknown "stuff" with normal mass just like regular matter but which we cannot observe with light; it doesn't appear to be emitting or noticably obscuring any kind of radiation. But we see the movement of galaxies in such a way that they appear to be responding to the mass of something that we can't see. Hence "dark matter" - we can't see it, but it seems to be some sort of matter. Think of it like leaves blowing in the wind - we can't see the wind, but we see the motion is causes.

Dark Energy is another hypothetical unknown "stuff" that seems to be adding, somehow, to the velocity of all objects in the universe. It is postulated because the universe appears to be accelerating in its expansion, which does not make sense given an empty, neutral vaccum and a bunch of matter in it. It should be slowing down or at best, expanding at a steady rate. Hence "dark energy" - we can't detect it, but some source of energy which is causing the expansion of the universe to accelerate.

Hope this helps.

Re:Difference?

[Aglassis]

It has been observed that galaxies on the whole do not obey Kepler's Laws of Planetary Motion. In particular, stars along different positions moving outwards from the core have about the same measured period (to do a complete orbit of the core). Kepler's Third Law says that the square of the period of a star is directly proportional to the cube of the stars' semimajor axis. Stars further out should have a much longer period (like Pluto) than those close to the core. Dark matter is an invention that compensates for discrepancy by saying that there is perhaps a large halo of non-detectable mass around the galaxy (about 10 or more times the observed mass). There are reasons to believe (too complex to go into here) that dark matter is not like ordinary matter but still has mass.

The Hubble constant, which was discovered by Edwin Hubble, showed that the universe was expanding. If the universe began at the Big Bang (and there is a significant amount of data to support this assertion) then the speed of expansion should be fairly straightforward to calculate. What is observed at great distances is greater than that value. For this reason scientists have named (very poorly) another potential fundamental force dark energy which accounts for the expansion. Dark energy would be like gravity, but repulsive, and is only significant at extreme distances (so that it wouldn't hurt the formation of galaxies).

Re:Difference?

[Anonymous Coward]

Dark matter is particles of matter that cannot be detected by emitted radiation but can be inferred through its gravitational effect.

Dark engery is a theoretical form of energy that has a strong negative pressure, an anti-gravity if you will.

Re:Difference?

[GHOST OF THE DEEP]

Hence "dark matter" - we can't see it, but it seems to be some sort of matter. Think of it like leaves blowing in the wind - we can't see the wind, but we see the motion is causes.

maybe more surch dark matter is leaves ,and we can see wind ,but we can`t see leaves (can, but whence if not)

Re:Difference?

[niktemadur]

Here's a bit more about the nature of Dark Matter, what theory thinks it is in a more specific manner. However, we must explain what "Normal" Matter is.

"Normal" Matter is matter that is influenced by the four forces of the universe. The first three are at the atomic and sub-atomic level, the fourth one is on the Relativistic Scale:

1. The Strong Force, keeping the atomic nucleus together, even as it is composed of neutral and positively charged particles.
2. The Weak Force, which makes the orbits of electrons decay over time. We know it also as Radiation.
3. The Electromagnetic Force, which creates attraction between atoms, creating molecules.
4. The Gravitational Force, which creates an attraction between masses.

Dark Matter of the WIMP variety (Weak Interactive Massive Particles) is UNAFFECTED by the first three forces. It is like a mist that congeals under gravity, but is never more than "ghostly", and since it cannot bond at the atomic and subatomic level, it is undetectable except by the gravity it creates.

Dark Matter of the MACHO variety (Massive Compact Halo Objects) consists of would-be stars that never made it, or stray planets and planetoids roaming around the galaxy.

Therefore, we call it Dark Matter because we haven't been able to detect it, but we can perceive the gravitational effect it has, everywhere we look. And I mean everywhere, since the figures say that between 90% and 98% of the universe consists of Dark Matter.

Re:Difference?

[niktemadur]

The way I understand it, the theoretical principle of Dark Energy is as simple as "Nature abhorrs a vacuum".

As galaxies speed away from each other, the space between them becomes emptier and emptier, until in some spots perfect vacuums appear. It is here that energy is spontaneously created from nothing, filling the empty space and pushing outwards the space around it.

Quite a concept, any way you care to look at it. Here are two takes on it:
1. Space has the capability of producing energy, therefore matter, from nothing, by itself. So what is matter, really?
2. A perfect vacuum creates a sort of "portal", and energy is transferred from "elsewhere". What would this "elsewhere" be?

As times goes by, galaxies drift further apart, more and more vacuums are created, more matter bursts forth...what's the scenario for the future of the universe under these conditions?

Re:Difference?

[Anonymous Coward]

Not really. Some posit that dark energy is due to quantum vacuum energy, but that's always present, it doesn't require the universe to "thin out". The energy is not "spontaneously created", either; it's always there. In other words, a vacuum ("nothing") always has some minimum energy. And this process does not create new matter in the universe, either.

Re:Difference?

[Anonymous Coward]

You know, there are perfect vacuums between subatomic particles. Nothing spontaneously appears in these small, perfect vacuums.

Oh, and they're all over the place.

Just letting you know.

Re:Difference?

[Anonymous Coward]

You forgot these fundamental forces:

5. The Duct Tape Force, which sticks things that are unstuck
6. The WD-40 Force, which unsticks things that are stuck

Re:Difference?

[MightyMartian]

What about vacuum energy and virtual particles?

Re:Difference?

[Alif]

Dark energy is made of particles with zero mass - something like photons or neutrinos, but dark. At the speed of light they have some energy.

On the other hand, dark matter is something like massive particles. It is speculated about some unknown baryons, quark clouds, small asteroids etc.

This teminology is not very precise - both of these types of particles have mass and energy, of course. However, they have a different effect in the Einstein equations governing the spacetime. So it is possible to distinguish them from theobservations of expansion of space etc.

Re:Difference?

[hesiod]

> 5. The Duct Tape Force, which sticks things that are unstuck
> 6. The WD-40 Force, which unsticks things that are stuck

Which brings me to my next point. Never try to remove duct tape with WD-40, or the universe may disappear.

Re:Difference?

[shadowbearer]

It would sure explain this timeline if instead of disappearing, the universe merely got warped, wrenched, and wefted a bit :)

I didn't do it! (Ok, I wasn't the first one!)

SB

Re:Difference?

[niktemadur]

They tried this up in Fermilab, but they did it within an Einstein-Bose Condensation Field, so catastrophe was averted.

They also tried an experiment in which a group of scientists put instant coffee in the microwave, and were never seen again.

How did the ripples get there?

[Dancin_Santa]

If there was nothing to push against, what would cause something to be held back and "ripple" as if there were some sort of repulsive force?

Let's say we've reached the edge of the universe, what happens when we step beyond that boundary? What is out there that would possibly hold back further expansion of our universe?

Re:How did the ripples get there?

[pintpusher]

Let's say we've reached the edge of the universe, what happens when we step beyond that boundary? What is out there that would possibly hold back further expansion of our universe?

this has plagued me for a long time. "they" say that there is nothing outside the universe, usually implying not even empty space (?) and now this. And still, if the universe is finite, it must have an edge (in some dimension or other for you torus types) and so what's out there? I suspect its something sticky or gooey and probably blueish-grey.

Re:How did the ripples get there?

[Anonymous Coward]

Let's say we've reached the edge of the universe, what happens when we step beyond that boundary? What is out there that would possibly hold back further expansion of our universe?

If you step beyond that boundary, the universe becomes couple of feet longer. You are part of the universe. The 'boundary' is because matter is moving only at a finite speed and beyond that boundary, no matter has reached yet!

Re:How did the ripples get there?

[TrekkieGod]

If there was nothing to push against, what would cause something to be held back and "ripple" as if there were some sort of repulsive force?

Not really related to the ripple they are talking about in the article, but "repulsive force" doesn't require something to push against. When students first learn of Newton's third law, "for every action, there's an opposite and equal reaction", teachers often give as an example that when you push against a wall, the wall pushes against you. That gives the idea to students that there must be something to push back against you (don't feel bad, some early rocket scientists thought the same thing). That is, however, not true. You don't need something to push against, you just need to exert a force in one direction, and there will be a a force in the opposite direction.

Because of this misconception, it was originally thought that rockets wouldn't work in space, because the exhaust they put out wouldn't be able to push against the atmosphere. But hey, they do!

Let's say we've reached the edge of the universe, what happens when we step beyond that boundary? What is out there that would possibly hold back further expansion of our universe?

Gravity. There's an attractive force between every object with mass. When you jump, you move away from the center of the earth, but only for a short time. You accelerate up, but then you start decelerating. You reach a maximum height, then you start accelerating back down. During the big bang, the universe started expending. It was originally thought that there would be a "big crunch", and the universe would stop expanding, than start collapsing towards the center. Then we discovered the universe was not only not slowing down in it's expansion, but actually accelerating. That made no sense, so Dark Energy was used to explain it (a force like gravity, but pushing outwards). Under that scenario, the universe would end not through a big crunch, but would simply become dark as suns die and black holes evaporate. If we don't need Dark Energy, maybe the big crunch theory will come back.

Re:How did the ripples get there?

[pintpusher]

Is this like trying to pick up the soap in the shower?

Re:How did the ripples get there?

[a gremlin]

please place a disclaimer in front of such statements, not all of us want to be forced to think...

Re:How did the ripples get there?

[Anonymous Coward]

You still need something to push against in order to create those ripples. Unlike vector thrust which only requires a directed force, a ripple requires a reflection of an energy wave.

Let's take a very simple example of a wave in water. It has a wave front and the energy contained in the wave form continues in a straight line until deflected or it runs out of energy due to friction. The only way to get a ripple is to reflect the energy back upon itself (like hitting a solid barrier). But even then, some energy is transmitted to the solid object because the reflected waves do not contain the same amount of energy as the original waves.

So in space, the huge burst of energy at the time of the Big Bang generated ripples, but what was reflecting the energy such that there were ripples, and how much of that energy was transferred to that "external" universe? If we can measure the intensity of the pre-ripple energy and compare it to the energy of the ripples, we can judge how much energy was lost to that "other" universe. But what is that external universe and how can it absorb that energy?

Ripples in our space mean a breakdown in the conservation of momentum, N's 2nd Law. It means that there is a net loss in energy for our single universe. However if we postulate that there is another universe that was able to absorb that lost energy we can trust that our natural laws are still in effect.

Re:How did the ripples get there?

[Anonymous Coward]

Not really related to the ripple they are talking about in the article, but "repulsive force" doesn't require something to push against.
Just flubber!

Re:How did the ripples get there?

[Anonymous Coward]

There is not an edge to the universe- note that when the universe expands, it is the universe itself expanding, time and space, and not just the stuff the universe contains. There is no space as we know it outside the universe- what we call the universe is the region where spacetime has unfolded into the dimensions we know and love.

Note that the topology of the universe likely makes it such that you couldn't leave the universe if decided to fly as fast as you can "away"- it's likely that you would curve back on the universe and be pointed back towards home. There are suggestions that our spatial dimensions as we know them arise from the space of the universe being arranged as a gigantic hypersphere. Imagine a two-dimensional universe on the surface of a sphere. Inhabitants could go and go and go, but unless they are somehow able to "pop" into the third dimension and leave the surface, no amount of motion on the sphere's surface will get them out of the universe. Now bump it up another dimension. Just as the two-dimensional inhabitants are stuck on a 2D surface, we are stuck on a 3D surface. Just as if you could pop out of the 2D universe, you'd see the entire universe as a sphere, if you could pop out of our universe, you'd see a hypersphere (technically, a 3-sphere, since the surface of the sphere, which we're on (I know it feels like "in") is three dimensional).

Re:How did the ripples get there?

[mfago]

When students first learn of Newton's third law, "for every action, there's an opposite and equal reaction", teachers often give as an example that when you push against a wall, the wall pushes against you. That gives the idea to students that there must be something to push back against you (don't feel bad, some early rocket scientists thought the same thing). That is, however, not true. You don't need something to push against, you just need to exert a force in one direction, and there will be a a force in the opposite direction.

Because of this misconception, it was originally thought that rockets wouldn't work in space, because the exhaust they put out wouldn't be able to push against the atmosphere. But hey, they do!

Uhmm ... rockets work due to conservation of momentum, not because of some mysterious reaction force.

Re:How did the ripples get there?

[Anonymous Coward]

The "ripples" they're talking about are just waves, not waves reflected off a boundary. There is no boundary needed to produce inflationary "ripples" in the early universe, and there is certainly no "external universe" involved, nor is there any violation of conservation laws.

Re:How did the ripples get there?

[CaptainMunchies]

When students first learn of Newton's third law, "for every action, there's an opposite and equal reaction", teachers often give as an example that when you push against a wall, the wall pushes against you. That gives the idea to students that there must be something to push back against you (don't feel bad, some early rocket scientists thought the same thing). That is, however, not true. You don't need something to push against, you just need to exert a force in one direction, and there will be a a force in the opposite direction.

Because of this misconception, it was originally thought that rockets wouldn't work in space, because the exhaust they put out wouldn't be able to push against the atmosphere. But hey, they do!

Uhmm ... rockets work due to conservation of momentum, not because of some mysterious reaction force.

And you know why conservation of momentum holds true? It's because of Newton's Third Law! Welcome to Physics 101, here's the C you earned.

Re:How did the ripples get there?

[Anonymous Coward]

Uh, the previous poster is correct, and never claimed that conservation of momentum wasn't due to Newton's third law. (Actually, I prefer to take conservation laws as more fundamental and posit that Newton's 3rd law is a consequence of conservation of momentum.)

Re:How did the ripples get there?

[gardyloo]

And you know why conservation of momentum holds true? It's because of Newton's Third Law!

After one has studied physics for a while, the reasoning that Newton's Third Law ==> Conservation of Linear Momentum is generally replaced by more of a feeling that momentum conservation is more basic (due to, in part, Noether's Theorem http://en.wikipedia.org/wiki/Noether's_theorem) and that Newton's Laws are simply a consequence of momentum conservation. The advantages of this abstraction are manifold (*cough*), but the "obvious" ones are cases in which forces are very hard to identify (such as in radiation reaction), and systems which may be much more immediately approached through Hamiltonian's or Lagrage's formulations rather than Newton's laws.

Re:How did the ripples get there?

[gardyloo]

One can see that there really *is* a reaction force in rocketry, and it's not mysterious at all: The fact that exhaust gases are directed in generally one direction away from the rocket engine means that they, before being expelled, bounced off of the engine parts in such a way as to go out the back. This "bounce" pushes the rocket in the opposite direction.
Of course, conservation of momentum holds true, but one *does*, in classical rocketry, have a reaction force between the hot gases and the rocket itself.

Re:How did the ripples get there?

[pintpusher]

I am quite familiar with this concept and others (like the torus {or in our case the hyper-torus} which leads to the enigmatic Asteroids screen-wrap) That still begs the question though... what's outside?

How many of the objects we see are actually 3D "slices" of 4D objecets? Are we 3D slices of 4d objects and thus our "Conscience" is a by-product of our 4D-ness? so many questions....

Re:How did the ripples get there?

[Anonymous Coward]

There doesn't have to be an "outside". A 2D "Asteroids" universe does not require a third (fourth, fifth, etc.) dimension; the screen is all there is.

Re:How did the ripples get there?

[sdo1]

If we don't need Dark Energy, maybe the big crunch theory will come back.

Or maybe the Universe reached its own "escape velocity" during the big bang.

-S

Re:How did the ripples get there?

[Anonymous Coward]

In other words, the rocket (engine) **is** pushing against something... the mass of its exhaust!

Re:How did the ripples get there?

[Almost-Retired]

Uhmm ... rockets work due to conservation of momentum, not because of some mysterious reaction force.

Not a very good explanation. Rockets work in space because the exhaust gases are, in the process of being accelerated out the back of the engine, are pushing equally hard on the walls of the engine thats burning the fuel. Since thats cone shaped, wider at the rear, its the net circular square area of the back flange of the motor that the gasses push against, and its anchor to the rest of the rocket transfers that push to the rocket proper. And don't forget that a little like the e=mc2 of Einsteins famous equation, the net power, minus some losses here and there, is still e=mv2, so the holy chalice/grail of the rocket is the one that moves the gas at the highest velocity at the face of the nozzle, with some of the flame cone actually being a velocity to pressure translation so in the end, the gas velocity, being highest out near the tip of the flame, serves to increase the felt pressure pushing forward on the engine proper.

The ion and plasma drives that use zenon gas, electrostaticly or thermally accelerated to a fraction of C speed, are many times more efficient in terms of the amount of push per pound of expendable than any chemically fired rocket can ever hope to be simply becasue of the 'fraction of C speed' is many times what a chemical fired gas generator can do.

I've heard/read of estimates that a xenon gas rocket, fired by a nuclear light bulb heat source (circa 30,000 degrees C) making a plasma out of the gas, could go to Alpha Centari in just a few years, as it would accelerate at a steady .05G's to the halfway point, then turn around and decelerate at that same rate. THat of course means it would have to be launched into leo by some other means before lighting the torch. If not turned around and slowed down, it would go by Alpha Centari at truely relativistic speeds, near .99 C. I haven't personally ran the math, but the article I read 2 decades back sure did. ISTR the article said it would only take about 20 tons of gas. That was with estimates of about 5 tons for the whole nuclear light bulb reactor so the total vehicle weight wouldn't be near as heavy as a Saturn5 at launch. We played with such a reactor at Rocky Flats for a while, but the natives (thats us people folks) got restless. I don't know if there ever was a true 'accident' involving one of them because basicly if the 'light bulb' envelope fails, the reaction is self quenching. One of the safest reactors ever developed, but the word nuclear was its death knell.

Sometimes I swear we are our own worst enemy.

--
Cheers, Gene
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
99.34% setiathome rank, not too shabby for a WV hillbilly

Re:How did the ripples get there?

[khayman80]

You accelerate up, but then you start decelerating. You reach a maximum height, then you start accelerating back down.

Umm... no. Your acceleration is always directed towards the center of the earth. Your velocity is initially upwards, then eventually turns downwards.

Re:How did the ripples get there?

[pintpusher]

AH HA! But then where do those damn little spaceships going bweep-bweep-bweep come from! Hunh?!

I thought so!

nyah

Re:How did the ripples get there?

[identity0]

That is, however, not true. You don't need something to push against, you just need to exert a force in one direction, and there will be a a force in the opposite direction.

Because of this misconception, it was originally thought that rockets wouldn't work in space, because the exhaust they put out wouldn't be able to push against the atmosphere. But hey, they do!

Uggg.... No. And you call yourself a Trekkie God?!

You say you need to exsert force in one direction. Remember, however, that F = m*a ; Without the 'm', there is no F. You need something to push against.

As for why rockets work in space, you need to look at what the rocket is actually pushing. The rocket is actually pushing against the exhast gasses in the engine and sending it flying back at enormous speed. Once the gas and rocket push apart after giving acceleration to each other, it doesn't matter if either one pushes against anything or not. The force is imparted from the pushing apart of the rocket and fuel/exhast, not the rocket pushing against atmosphere or launch pad via exhaust.

People didn't think about this in the early days of rocketry because they didn't think a little gas coming out of the end of a spout could be enough to make a huge rocket go by itself. But think about it, most of the volume (and probobly the mass) of a rocket like the Saturn Vs are in the form of fuel and oxidizer. All that stuff ends up being shot backwards at tremendous speed, so you get a tremendous amount of force just from pushing fuel out the back. The amount of force on the rocket would be F = (mass of fuel + oxidizer) * (acceleration of exhaust gasses).

I don't know about the rest of the parent poster's comment, but given how wrong he got simple Newtonian physics, I don't think I would trust the rest of his comment, either.

Re:How did the ripples get there?

[Anonymous Coward]

It is important to remember that analogies only go so far, or in on other words, why do you believe the universe in this case will act exactly like waves in water?

Re:How did the ripples get there?

[Walrus99]

"Ripple in still water, when there is no pebble tossed, nor wind to blow."

--The Grateful Dead explain the creation of the universe from a quantum vaccum fluctuation.

Re:How did the ripples get there?

[Anonymous Coward]

Yes, but you don't open a black hole that attracts other prisoners in the process. You get the idea.

Re:How did the ripples get there?

[jfengel]

I'd say that's almost completely true, with one caveat: in order for you to jump, you have to apply a force to something which gives you an upward acceleration, if only momentary. You go from a vertical velocity of zero to a positive one. But the instant you leave the ground, your acceleration is purely towards the ground.

Re:How did the ripples get there?

[bill_mcgonigle]

If there was nothing to push against, what would cause something to be held back and "ripple" as if there were some sort of repulsive force?

If our universe really did occur because of a collision of two higher-level 'branes, perhaps the ripple occurred on that level. Maybe the universe can react to those forces in a cohesive way.

Re:How did the ripples get there?

[Alsee]

Let's say we've reached the edge of the universe, what happens when we step beyond that boundary?

There is no edge. Imagine it was an expanding earth. You can walk as far as you want, but you will never step beyond the boundry of the earth.

-

Re:How did the ripples get there?

[Anonymous Coward]

Maybe the universe is still "exploding". "Combustion" hasn't finished. It's a very long lasting explosion. Could explain the push that's still accerating everthing? Our point of view should be similar to a single cell bacteria's( more likely a single molecule's) inside an exploding atom bomb. Or maybe the universe doesn't exist in a void. Something could be pulling on it from the "outside". That would be wierd.

Re:How did the ripples get there?

[iminplaya]

I've heard/read of estimates that a xenon gas rocket, fired by a nuclear light bulb heat source (circa 30,000 degrees C) making a plasma out of the gas, could go to Alpha Centari in just a few years, as it would accelerate at a steady .05G's to the halfway point, then turn around and decelerate at that same rate.

You probably saw it here.

Re:How did the ripples get there?

[Almost-Retired]

First I've seen of that ficticious story. It makes a nice read, but ignored the gravity wells that must be climbed in and out of. That lack makes it totally undoable in the real world, and anybody with common sense can figure that out.

What I read was maybe a 5 years after the moonwalks in one of the science fact articles in Analog magazine, and I think it may even have been discussed in Sci. Am. a time or 2 over the years. It gets a bit of ink from time to time, but TPTB see the word nuclear and toss it in the fireplace for fuel.

--
Cheers, Gene
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
99.34% setiathome rank, not too shabby for a WV hillbilly

Re:How did the ripples get there?

[iminplaya]

I don't know what the word is for this form of space travel, but I'm also pretty sure I heard about this before any of the moon launches. Maybe only the "crackpots" were discussing it. I don't remember. If we were ever to travel to other systems, it seems that the gravity well would only be a problem for a small portion of the trip, and wouldn't effect overall efficiency. The link was meant as a joke. You did know that, right? The mods with a sense of humor are taking the holidays off. I wish I could attach a laugh track to my posts. Damn spring breakers cluttering up our beaches :-)

Re:How did the ripples get there?

[prichardson]

Just to pick a nit,

When you jump off the ground you don't start accelerating back toward earth when you stop moving upward. You start accelerating toward earth as soon as you leave it. Your velocity is the thing that changes as you move through time.

DE=DMC2

[Anonymous Coward]

Space beyond the edge of Universe

[igny]

"It requires only a proper accounting of the physical effects of the ripples beyond our cosmic horizon,"

Ripples of what? Is there space beyond the cosmic horizon? Or by horizon they meant observable part of Universe?

Re:Space beyond the edge of Universe

[ari_j]

Yes, there is space beyond the cosmic horizon. The horizon on Earth is just the farthest you can see because of the curvature of the planet's surface. The planet keeps going beyond the horizon - the horizon is a function of the observer. The same applies to the universe, although I am not knowledgeable enough to tell you if the cosmic horizon is the limit of what we can see because of the distance, because of a higher-dimensional curvature of the universe, or because of something else.

Re:Space beyond the edge of Universe

[Anonymous Coward]

although I am not knowledgeable enough to tell you if the cosmic horizon is the limit of what we can see because of the distance, because of a higher-dimensional curvature of the universe, or because of something else.

Because of light speed. Since nothing can travel faster than light, you can't receive a signal from anywhere in the Universe that is farther from you than the distance light could have travelled since the formation of the Universe (14 billion years approx.)

Re:Space beyond the edge of Universe

[Mycroft_VIII]

A bit more precise answer would account for the expansion of the universe as well. We can see farther than c*AOU(age of universe) would imply as objects were closer once uppon a time.
Even moreso if the universe went through a period of ftl expansion as some theorize.

Mycroft

Re:Space beyond the edge of Universe

[Darth Muffin]

Since the universe is expanding, objects farther away from us are retreating at a faster pace. The "edge" of the universe for us is when you get far enough away that the universe is retreating at the speed of light. We can't see beyond that.

Re:Space beyond the edge of Universe

[vhogemann]

The limmit is probably caused by the speed of light, We can only "see" something if the energy it irradiates arrive at Earth.

So, if a new star is born now at 5 light years from here, we'll see it only 5 years later when its light hit Earth.

Then, if the universe is T years old, and is expanding at the speed of light, we could only see what is T light years from here.

Of course its just an opinion, since i really suck at phisics.

Re:Space beyond the edge of Universe

[Ikester8]

Mmmmmmmmmmaybe. I'll never tell.

Re:Space beyond the edge of Universe

[Anonymous Coward]

FTL expansion period? You mean there's no FTL expansion going on at the very moment?

Re:Space beyond the edge of Universe

[gr_g_eek]

"Since nothing can travel faster than light" I would say "since nothing can travel at the speed of light". Only light has this advantage.

Re:Space beyond the edge of Universe

[Mycroft_VIII]

I think most theories involving the universe going through a period where space itself was expaning faster than light have it occuring for a short time early on.

Mycroft

Inflation...

[ackthpt]

Apparently, ripples from inflation in the early universe may account for the observed expansion rate of the universe."

Hmm. Better check the exchange rates on Altairian Dollars, Flainian Pobble Beads and the Triganic Pu.

Has anyone contacted Alan Greenspan about this?

Re:Inflation...

[niktemadur]

But on Altair they pronounce them "Thallers".

Comment removed

[account_deleted]

Comment removed based on user account deletion

It won't be long...

[micsmith]

...before the true cause of the universe is revealed and maybe what the true purpose of being human is. Sure, I'm a troll. http://www.falundafa.org

Eddies in the space time continuum

[starling]

Arthur : Oh, is he?

Re:Eddies in the space time continuum

[Anonymous Coward]

How did Eddy get there?

Re:Eddies in the space time continuum

[Tenebrious1]

Did Fermilab find Eddie's couch?

Re:Eddies in the space time continuum

[starling]

It's still stuck in an impossible place half way up the stairs.

string theory Nova

[Fox_1]

Nova did a great piece on the all of physics (a lot on the universe and big focus on Quantum Mechanics and String Theory). It's pretty good if you are trying to find commonplace explanations of some of the theories the article just mentions and doesn't explain.

Re:string theory Nova

[eobanb]

That would be The Elegant Universe, by Brian Greene. It's actually based on a book that he wrote, which is EXTREMELY well-written. I highly recommend it if you're at all interested in this stuff.

Re:string theory Nova

[loraksus]

Might be redundant, but you can watch the show online by clicking a link on that page. Quite decent quality.
There is also a HDTV .torrent out there - 3.14 GB, much nicer quality.

Re:string theory Nova

[OpenSourceOfAllEvil]

FAR more interesting than The Elegant Universe is his subsequent book The Fabric of the Cosmos: Space, Time, and the Texture of Reality. I highly recommend this to anyone that was interested by his earlier work or the various discussions here.

Most posts here seem to be quoting science from decades ago. The errors and misconceptions too numerous. It is clear that many have no idea how far we have come in understanding everything all the way back to and including time zero, including what even caused the Big Bang. It takes a mass of just 10Kg at the Big Bang to explain all known matter and energy in the unverse today. The Inflationary Model today is nothing like the originally proposed Big Bang. It predicts and explains what we currently observe.

Fermilab's proposal is fascinating and if they are correct could have a serious impact on modern research such as the search for the Higgs boson that will be done at the CERN supercollider. The Higgs Field is related to the Inflaton Field responsible for the initial expansion.

The universe is very possibly 2 dimensional, you can think of a Pac-Man screen. If string theory is correct, all known matter is made of open ended strings. Open ended strings must be attached to a d-brane, a one or more dimensional membrane predicted by string theory. It is very likely our entire universe is attached to a 2 diminsional d-brane. This prevents our universe from any of those sci-fi parralel or other universes we love reading about. The only thing that can possibly escape is gravity, hence Gravity Phones for those of you that watched the Elegant Universe.

Re:string theory Nova

[Anonymous Coward]

Speaking of errors and misconceptions.. we still know very little about what caused the Big Bang (or even whether there really was one, as such). Inflationary models such as Linde's eternal inflation are one kind of explanation, but there are many others, including from diverse theories of quantum gravity. We don't know if inflation played a role in the Big Bang, or just after it.

The proposal being discussed in this thread also has no implications for the search for the Higgs. We don't know whether the Higgs is the inflaton, and this proposal sheds no new light on that question. Perhaps subsequent observations might, but they won't necessarily be dark energy observations. And in any case, the LHC is likely to just see the Higgs before any cosmological models of inflation can tell us much more about it.

The universe is not very possibly 2 dimensional. It is probably at least 4 dimensional, and maybe higher. In M-theory braneworld scenarios, our unvierse is (not "is attached to") a 3-brane (not a 2-brane). And no, open string don't have to be attached to branes; they can be.

Re:string theory Nova

[MightyMartian]

AS long as you take some of what Greene says about string theory with a grain of salt. He rather glosses over the substantial difficulties that string theory still has. He's a bright guy, but he does have a bias that might no be obvious to someone not familiar with the great and ongoing debates about strings.

Re:string theory Nova

[possen]

Scientific American this month has a article called the Misconceptions of the Big Bang this month (March 2005). This article attempts to correct the errors that even experienced scientist make about how the Big Bang theory works. Until I read this article I was somewhat skeptical of BBT because the misinformation out there causes the theory to make little sense.

Re:string theory Nova

[Darby]

AS long as you take some of what Greene says about string theory with a grain of salt. He rather glosses over the substantial difficulties that string theory still has.

My understanding is that the major difficulties with it are:

1. It's entirely possible that we will never be able to build a particle accelerator that can generate enough energy to experimentally detect the difference between a zero size point particle and a really freaking small, yet non-zero size string
2. The actual mathematics of the theory are too complex for anybody to quite know how to write down the equations. Infact even approximations to these equations don't really exist yet.
3. There are somewhere around 10 thousand different families of manifolds which could possibly be the correct one which the curled up dimensions are in the shape of. Also, we can not experimentally determine which one for essentially the same reason as in #1

Are there other substantial difficulties? These are the ones he makes very clear in his book.

Roadrunner Cosmology

[Tablizer]

So it is like when Wile E. Coyote yanks the road up and down and the ripple gets bigger and bigger as it moves toward the Roadrunner? (and then bounces off a mountain side, comes back, and smashes Coyote.) Next you know they will find a giant U magnet at the edge of the universe.

Dark Tomatoes and Universal Expansion

[Mulletproof]

"Apparently, ripples from inflation in the early universe may account for the observed expansion rate of the universe."

Can't we just admit we don't have a freakin' clue and move along? "Well shoot, I think TOMATOES might explain the expantion of the universe! LOTS and LOTS of TOMATOES! That are, um, dark. Which is why you can't see them. And they ripple. And stuff."

Re:Dark Tomatoes and Universal Expansion

[LokieLizzy]

Heretic! Science is on the march, and it's coming to your doorstep to take you away!

Re:Dark Tomatoes and Universal Expansion

[dougjm]

I agree. Lets face it, the moon is as far as a human has ever travelled in space (ie in terms of distance away from the earth) and that was 30 odd years ago. How can we sit here on this planet and think that we can just work it all out like that.
I always like to think of the start of the last centuary - around 1900 - victorian scientists had it all worked out, think dalton sphere and then think 50 years in the further on when we'd seen the atom split.
I'm not going to claim that anyone's wrong and i'm no expert myself but isn't it just possible that we really don't understand in any way what we're talking about?? I mean are you really sure that if you take all the matter and light and heat and energy in the entire universe and compress it into a little ball so that it explodes that photons won't go 4x10^8 m/s??

Re:Dark Tomatoes and Universal Expansion

[vsprintf]

"Apparently, ripples from inflation in the early universe may account for the observed expansion rate of the universe."

Would you all please just shut up about that? Do you realize what Greenspan is going to do when he hears about this?

Re:Dark Tomatoes and Universal Expansion

[DaoudaW]

Have you ever read Einstein's Relativity: The special and general theory? Ok, I didn't think so. Most people assume that it's full of equations that a normal (read non-genius) person wouldn't have a chance of understanding. But its not. Pop over to Project Gutenberg and pick up a copy. It's quite readable and full of examples about poles and clouds and railroad cars and embankments and lightning. Sure there's some math, but less than the typical high school calculus book.

What I'm trying to say is that if Einstein had posted on slashdot, you'd probably have made fun of his examples and said he didn't know what he was talking about. But its exactly the kind of speculative thinking that is exhibited in this thread that led to the theory of relativity.

Can somebody fill me in here...

[Anonymous Coward]

1. What is "dark energy"?
2. What is a "cosmological constant"?

Re:Can somebody fill me in here...

[Anonymous Coward]

A cosmological constant is like a global variable, only with broader scope and remaining constant.

Re:Can somebody fill me in here...

[Anonymous Coward]

The second question might be the better place to start. Back when Einstein developed his field equations for general relativity, he noticed that his equations predicted that the universe was expanding. This was unacceptable to Einstein, who thought the universe was a permanent, largely unchanging thing. He inserted a "fudge factor" called the cosmological constant that balanced out the expansion. It wasn't much later, though, that experiments strongly suggested the universe really was expanding, and Einstein dropped the cosmological constant, calling it "my greatest mistake."

Now, for many years, it was assumed that the rate of expansion could be one of two things- either the matter in the universe would be sufficient to pull the universe back in under its own gravity, causing a Big Crunch, or the matter density would be too low and expansion would slow, but not stop. Either way, gravity would slow the expansion. However, recent experiments showed something shocking- instead of slowing down, the rate of expansion was speeding up! There seemed to be a force opposing the force of gravity- a force that physicists call "dark energy."

Now, according to the article, it may not be a new fundamental force, but rather rebounding gravitational waves from just after the beginning of the universe- from an event called inflation where the early universe suddenly expanded by a factor of like 10^40 in less than a nanosecond. There's not concrete proof that this inflation occurred- Alan Guth can book his hotel room in Stockholm if some is found- but it very nicely explains a number of features of the universe, particularly the way matter is distributed in stars and galaxies.

Re:Can somebody fill me in here...

[6800]

The dark energy question is answered by an earlier post.

cosmological constant: a term in Einstein's general relativity equations that leads to an acceleration of the expansion of the Universe. Usually denoted by the capital Greek letter Lambda when expressed with units of inverse length squared, or by the lower-case Greek lambda when normalized to the critical density like Omega. http://www.astro.ucla.edu/~wright/glossary.html

Re:Can somebody fill me in here...

[mamladm]

When Einstein found that according to his mathematical models, the universe was expanding, he didn't think this made any sense and so he invented the cosmological constant to his formulas to neutralise the expansion of the universe.

When applying the "correction" the universe appeared to be standing still and everything was hunky dory, at least until many many years later when evidence was mounting that the universe was indeed expanding.

Einstein then called the cosmological constant the greatest blunder of his life.

Apparently, his formulas were more trustworthy than even he himself was willing to believe.

Question about usenet (LEGAL/ILLEGAL)

[Anonymous Coward]

Hi, I just started using usenet for porn and saw that theres a lot of child porn posted. I did not download any images but you can guess what it is by just looking at the message subjects.

Should I stop using usenet just because some jackass posts child porn into other (legal) porn newsgroups??

suppose some pictures get downloaded into my computer. can i be in trouble?

please advise.

WWDVS?

[LokieLizzy]

(What would Darth Vader say?)

"Do not be so proud of this cosmological terror you have created. Its existence pales when compared to the power of the Dark Side."

Re:WWDVS?

[Anonymous Coward]

obviously, the dark-side itself can't pale, at least not if it is to remain ...er.. DARK!

I'm not an expert...

[chazR]

but Sean Carroll is. And he's not convinced.

Re:I'm not an expert...

[Anonymous Coward]

but Sean Carroll [blogspot.com] is.

Perhaps he is. But the [blogspot.com] doesn't exactly scream "CREDIBLE!", does it?

Re:I'm not an expert...

[Anonymous Coward]

But the [blogspot.com] doesn't exactly scream "CREDIBLE!", does it?
Perhaps it does not, however...

Re:I'm not an expert...

[muizenkatten]

International scientists say they have gathered fresh data which suggests most of the energy in the Universe is likely to be in an invisible and presently unknown form. Using the world's most powerful telescopes to make radio pictures of thousands of distant quasars - some of the brightest objects in the sky - the scientists calculated that two thirds of the cosmos is made up of dark energy. The findings fit in with current thinking as astronomers have calculated that the total mass of all the visible galaxies only makes up about one-third of the critical density needed to satisfy the best current theory about the early Universe. It may also explain what is causing the expansion of the Universe to accelerate. Dark energy seems to push the very fabric of space apart causing the Universe to expand ever faster. The most convincing evidence came from recent measurements of distant supernovae which showed that the Universe is indeed expanding with increasing pace. However dark energy only affects the properties of the Universe over very large distances - like exploding stars in far away galaxies - and so it is very difficult to measure using current technology. --- The research tallies with large galaxy surveys http://news.bbc.co.uk/2/hi/science/nature/2444123. stm/

Re:I'm not an expert...

[muizenkatten]

http://www.fnal.gov/>

Re:I'm not an expert...

[Gordon Meier]

Dark energy Feature: May 2004 New evidence has confirmed that the expansion of the universe is accelerating under the influence of a gravitationally repulsive form of energy that makes up two-thirds of the cosmos It is an irony of nature that the most abundant form of energy in the universe is also the most mysterious. Since the breakthrough discovery that the cosmic expansion is accelerating, a consistent picture has emerged indicating that two-thirds of the cosmos is made of "dark energy" - some sort of gravitationally repulsive material. But is the evidence strong enough to justify exotic new laws of nature? Or could there be a simpler, astrophysical explanation for the results? The dark-energy story begins in 1998, when two independent teams of astronomers were searching for distant supernovae, hoping to measure the rate at which the expansion of the universe was slowing down. They were in for a shock: the observations showed that the expansion was speeding up. In fact, the universe started to accelerate long ago, some time in the last 10 billion years. Like detectives, cosmologists around the world have built up a description of the culprit responsible for the acceleration: it accounts for two-thirds of the cosmic energy density; it is gravitationally repulsive; it does not appear to cluster in galaxies; it was last seen stretching space-time apart; and it goes by the assumed name of "dark energy". Many theorists already had a suspect in mind: the cosmological constant. It certainly fits the accelerating-expansion scenario. But is the case for dark energy airtight? The existence of gravitationally repulsive dark energy would have dramatic consequences for fundamental physics. The most conservative suggestions are that the universe is filled with a uniform sea of quantum zero-point energy, or a condensate of new particles that have a mass that is 10-39 times smaller than that of the electron. Some researchers have also suggested changes to Einstein's general theory of relativity, such as a new long-range force that moderates the strength of gravity. But there are shortcomings with even the leading conservative proposals. For instance, the zero-point energy density would have to be precisely tuned to a value that is an unbelievable factor of 10120 below the theoretical prediction. In view of these extreme solutions, perhaps it is more reasonable to expect a conventional explanation for the accelerating expansion of the universe based on astrophysics (e.g. the effects of dust, or differences between young and old supernovae). This possibility has surely kept more than a few cosmologists awake at night. Until recently the supernova data were the only direct evidence for the cosmic acceleration, and the only compelling reason to accept dark energy. Precision measurements of the cosmic microwave background (CMB), including data from the Wilkinson Microwave Anisotropy Probe (WMAP), have recently provided circumstantial evidence for dark energy. The same is true of data from two extensive projects charting the large-scale distribution of galaxies - the Two-Degree Field (2DF) and Sloan Digital Sky Survey (SDSS). Now a second witness has testified. By combining data from WMAP, SDSS and other sources, four independent groups of researchers have reported evidence for a phenomenon known as the integrated Sachs-Wolfe effect. These groups have found that the gravitational repulsion of dark energy has slowed down the collapse of overdense regions of matter in the universe. The case for the existence of dark energy has suddenly become a lot more convincing. Charting the cosmic expansion The cosmic expansion, discovered in the late 1920s by Edwin Hubble, is perhaps the single most striking feature of our universe. Not only do astronomical bodies move under the gravitational influence of their neighbours, but the large-scale structure of the universe is being stretched ever larger by the cosmic expansion. A popular analogy is the motion of raisins baking in a very large cake. As the cake rises, the distance between any pair of

Gravity leaks

[Tablizer]

I've read another hypothesis recently: that gravity slowly "leaks" into other dimensions so that over long distances it's attractive force diminishes, and that is why the universe is flying apart. The average distances between the galaxies has now reached a threashold where the leakage makes a big difference, giving the appearence of a relatively sudden expansion speedup.

Re:Gravity leaks

[Anonymous Coward]

Where are these "other dimensions", exactly? Is this some kind of string theory thing?

Re:Gravity leaks

[XanC]

Even if gravity were zero, the universe would then expand at a constant rate. But it appears to be accelerating, implying some kind of negative gravity.

Re:Gravity leaks

[the_2nd_coming]

that "gravity leakage is due to the fact that gravitons (in super string theory) are closed strings so they are not tied to our brane like all the other particles. this gives them the ability to move between branes.

Re:Gravity leaks

[the_2nd_coming]

M-Theory. Gravitons can escape to other branes (other 10 dimensional surfaces that hold universes because they have a closed structure with respect to our brane (complete circle) where as all other elemental particles are open so they are physically connected to our universe and cannot escape.

I like the idea of M-Theory.. the only thing is that we do not have the mathematics to describe it yet..... Personally I think the problem lies with the undefined values of 1/0. if we can define that as u and define u*u^{-1} = 1 then we can show that 0|n because n = 0*un.

Re:Gravity leaks

[Stalyn]

The hypothesis in question was explained here

Also here for the braver souls.

Re:Gravity leaks

[Tablizer]

Even if gravity were zero, the universe would then expand at a constant rate. But it appears to be accelerating, implying some kind of negative gravity.

Something can still be accelerating even though it has not reached a certain max speed. For example, a car may reach a maximum of 120 mph by itself. But a heavy trailer may slow car B to 30 mph. If that heavy trailer slowly melted over time, then car B would be accelerating even though it has yet to reach 120mph.

Re:Gravity leaks

[Ohreally_factor]

Does M theory hypothesize N-dimensional zombies?

Re:Gravity leaks

[Anonymous Coward]

why fix a partial boundary value problem by redefining the math? doesn't that just obscure the physics?

Re:Gravity leaks

[jackbird]

With the engine off?

Re:Gravity leaks

[the_2nd_coming]

hardly. That is like saying that the complex numbers are a redefining of math.

when all we knew were the real numbers \sqrt{-1} was an undefined number. then they created a number for it called i.

by defining u = 1/0 you now have a way to define an undefined value in the complex numbers. it is also very useful in the case of M theory at first glance.

If a graviton leaves our universe, the place that we define everything from, then it is an undefined value to us, yet in M-theory it still needs a way to be represented in order to follow it from one brane to the next.

Re:Gravity leaks

[the_2nd_coming]

let me clear up something... when I say u is a way to define an undefined value in the complex numbers, I mean that 1/0 is undefined in the complex numbers and that u is a way to define it... u is NOT a member of the complex set of numbers, it would be a member of the undefined set of numbers denoted by nu

Re:Gravity leaks

[Anonymous Coward]

What the flying fuck?

Re:Gravity leaks

[klreed42]

Not so much a commentary as a question I'd like to consider.

When I consider things like artificial modifications to mathematical models, and non-closed form universes, it makes me believe that our fundamental mathematical equations are somehow incomplete (Not a real big stretch there anyways).

A gas will expand to fill the space provided, and yet will also contract based on gravitational forces. Is it possible that the very presense of nothing beyond the 28Billion light years is the cause of the universe expanding, just like gas? And is it possible to evaluate this hypothesis based on how Earths atmosphere, and the sun's atmosphere (and the oort cloud) behave?

Re:Gravity leaks

[Alsee]

nothing beyond the 28Billion light years

You can only see to about a 25 mile horizon standing on earth, but beyond that horizon is exactly the same as here. There is no edge and there is no "empty space" for anything to expand into.

The big bang was not an explosion like a handgrenade.

-

question about usenet (legal/illegal)

[Anonymous Coward]

Hi, I just started using usenet for porn and saw that theres a lot of child porn posted. I did not download any images but you can guess what it is by just looking at the message subjects.

Should I stop using usenet just because some jackass posts child porn into other (legal) porn newsgroups??

suppose some pictures get downloaded into my computer. can i be in trouble?

please advise.

This exact comment has been posted. Try to be more original.....

Isn't that ...

[Anonymous Coward]

... inconsistent with the recent data from the Large Hardon Collider? Could anyone explain that expanding/shrinking phenomenon in lay terms please?

Re:Isn't that ...

[Anonymous Coward]

...Large Hardon Collider...

snicker...

...expanding/shrinking phenomenon...

guffaw!

Gerald Ford was right all along

[AtariAmarok]

"Apparently, ripples from inflation in the early universe may account for the observed expansion rate of the universe." "

Does anyone still have one of those "WIN" buttons left? Perhaps if enough of us wear them, we can stop the catastrophic overexpansion of the universe.

OK, keep talking

[mcc]

Does any of this have anything to do with "Dark Matter"? Or was "Dark Energy" just given a similar name because it sounds catchy?

Or is it all just those dang midicholorians again?

Re:OK, keep talking

[mcc]

OK, thanks.

Re:OK, keep talking

[Hatta]

Dark matter is so named because we literally cannot see it - it's dark at all wavelengths. Dark energy, on the other hand, is dark in the intellectual sense - we don't know what it is. They're two entirely different things.

Are you implying that we know what dark matter is? And if so, how do we know, considering that we can't detect it.

Re:OK, keep talking

[daVinci1980]

Dark matter is "dark" in that it does not emit its own radiation. There's a big difference between "doesn't emit its own radiation" and "cannot see it".

The former is dark matter. The latter would be a black hole.

Re:OK, keep talking

[imsabbel]

Well, im not really up to date, but there are 2 canditates for dark matter:
Machos (massive compact halo objects) and Wimps (weakly interacting massive particles).
The latter are suppossed to be particles not being affected by any force but gravity (just like neutrinos are not affected by strong force or electromagnetic forces). Creation could have happened during the big band (those mysterious first 3 minutes).
Machos OTOH would be normal matter, but "dark" in the sense of "no active emission". What you would normally expect from the name. Could be cold dust nebula, primordial black holes, all that stuff.

Dark matter is suspected because it HAS to be there in order for the physical rules to work (if you think that kind of reasoning is invalid, well, it served us well with the neutrino...). For example spiral galaxies differential rotation just couldnt be the way it is with the visible matter. There HAS to be something else. Or lots of cosmologic stuff that nobody really understands :)

About detection: Machos have been detected (there was a slashdot story a while back). Prime candidate for detection is gravitational microlensing.
About wimps... i personally like the philosophical concept, but dont have any idea how you could detect them if they are really not interacting exept with gravity. Maybe if we could meassure gravity waves, there could be dispersions caused by them in otherwise matterfree space, but we cant even detect those at all...

Re:OK, keep talking

[nine-times]

Well, part of the reason each were called "dark" is because they were mysterious. "Dark matter" because there were measurable effects where no matter could be detected, and therefore it was presumed that there must be undetectable matter causing the effects. "Dark Energy" came later to explain measurable effects where no force could be discerned, and so it was presumed that there must be an unknown force causing the effects.

Theories about what "dark matter" and "dark energy" were came later.

Re:OK, keep talking

[Anonymous Coward]

Dark matter was deemed "dark" because, literally, it was non-luminous. Dark energy was called "dark" in analogy to dark matter, being something mysterious that caused measurable effects (as you say).

Not Funny, Insightful

[MAdMaxOr]

Mod parent insightful. We know very little about the early universe, but we sure have a lot of research articles that are being continually published and refuted.

Re:Not Funny, Insightful

[wanerious]

Insightful? What would you like to have happen? Publish fewer articles? Not research it so much? Sheesh.

This anti-intellectualism stain in /. responders is saddening. Basically it seems to be, "I don't understand what they're talking about, so I think I'll make fun of them" or "I don't understand the thousands of papers that have been published, so I'm going to shout something superior-sounding from the cheap seats". Dismissing a beautiful and maturing field of physics with "we don't really know anything, so give up" is a sophomoric and pretentious reaction.

Sure, there's a bunch that we don't understand, but please realize that this is the way science works. Nature is too subtle for us to have canned and precise answers for her behavior. Cosmologists are rightly invigorated by the new data, and ought to be encouraged to research and refute each other's ideas.

Re:Not Funny, Insightful

[Anonymous Coward]

What happened at the only party you were ever invited to? It was your birthday party, right?

energy

[compressedaudio]

Is it possible that all the energy coming from stars over all that time and distance has some effect on everything else?

eg.

If 10 billion light years worth of protons travelling from a galaxy had a mass, does it's own emitted energy pull it away from the bang? and do other stars' emitted energy push away at the accellerating galaxies?

What was that experiment confirming Earth's 'tearing' effect of gravity the sattelite?
I'm just wondering if emitted energy pushes away in the same way that 'tearing' mass pulls sattelites slightly more.

Sorry, I've so many questions like this, can you answer them slashdot?

-
yeh

Re:energy

[compressedaudio]

excuse my language, I meant photon not proton, although protons may also have an effect.

Re:energy

[Jerf]

If 10 billion light years worth of protons travelling from a galaxy had a mass, does it's own emitted energy pull it away from the bang? and do other stars' emitted energy push away at the accellerating galaxies?

You're suffering from what I call the Big Number Fallacy; while the number of photons may be large, the amount of matter is so much larger it completely swamps it.

More to the point, conservation of energy and mass<->energy equivalency says that when a star emits a photon, it loses that energy in mass. Obviously, stars are not routinely boiling away due to photon energy losses, or indeed, energy losses at all. Not enough mass-energy is floating around as photons to affect anything.

What was that experiment confirming Earth's 'tearing' effect of gravity the sattelite?

I think you're referring to the "frame dragging" experiment, which is almost completely unrelated, except inasmuch as they are both related to relativity.

I know it's fun to play word games with the shiny Physics and Cosmology terms, but if you really care, you need to learn the real stuff, not merely keywords. I rather liked this; the fact that it's seriously tough shit is a good sign, if you get my drift. If it's easy, you're just playing word games.

Re:energy

[compressedaudio]

Thanks for the correction.
that link is serious!

What about this one...

A theory I've kept for a long time is that the universe is always exploding (and always has done) and is infinite towards the centre and infinite going outwards.

Can objects we can't see over the horizon be moving away from us faster than the light can reach us?

13.7 odd billion years seems like a long enough time for mass to get to C speed relative to us. I know I should go to university for all this, but I would like to know...
If something does accelerate past C speed from an observer, would its' emitted wavelengths continually shift toward red, microwave, radiowave then be so large that they are un-noticable?

Re:energy

[Anonymous Coward]

There are some eternally-expanding models like de Sitter cosmology, but they don't appear to describe our universe. There isn't a "center" or "edge" to the universe, by the way, at least as far as we can tell. (Unless you're talking about the observable universe, which is centered at us and is bounded by our cosmological horizon.)

Yes, objects past the horizon can move away faster than light can reach us. In fact, that's exactly the case in a universe with accelerating expansion.

There are ways to detect WIMPs similar to how neutrinos are detected, observe a big tank of fluid and see if there are any flashes of light. That assumes that they interact non-gravitationally, though, just weakly. Otherwise, yeah, it's pretty difficult, you'd have to measure gravitational waves from their influence in the early universe (very difficult).

Re:energy

[MightyMartian]

My understanding is that there is nothing preventing the expansion from exceeding C. Matter itself cannot be accelerated to C, but the Universe itself could be expanding at a greater rate.

If Dark Energy is not needed

[sharkey]

Then there's no need for Branigan's Law.

Re:If Dark Energy is not needed

[Anonymous Coward]

No need for Brannigan's Law? Brannigan's Law is ike Brannigan's love: hard and fast.

Comment removed

[account_deleted]

Comment removed based on user account deletion

Seriously now

[Camel Pilot]

The universe is expanding at an accelerating rate not because of some dark matter but because of the gravitational attraction of other universes in the local vicinity of our own. sheeshh why do folks want to believe we are special with our own little private universe.

Just like at various times in history, humans believed that our tribe was the center of the universe, then the earth, then the sun, and now no one wants to think "outside the box" so to speak, and so they invent dark matter to account for observations that don't match up.

Re:Seriously now

[mOdQuArK!]

The universe is expanding at an accelerating rate not because of some dark matter but because of the gravitational attraction of other universes in the local vicinity of our own.

Really? How do you know?

Re:Seriously now

[Anonymous Coward]

Experimentation in the 60's?

Re:Seriously now

[buckpounders]

Right on brother. So...taking your theory seriously, how would you explain the uniformity of the background radiation?

Re:Seriously now

[Anonymous Coward]

because of the gravitational attraction of other universes in the local vicinity of our own.

Maybe something outside our light horizon, which is the "visible universe", but the universe as a whole?

E.G. if something has a "normal" gravitational effect on matter/energy within the universe, isn't it definitionally part of the universe? (it doesn't matter whether it is within our light horizon or not).

Re:Seriously now

[Camel Pilot]

Oh that is easy. We assume that the background radiation should be a gradient since we are thinking one universe and one big bang. But suppose that universes are popping off like popcorn all around our "special" universe and take sum of the superposition of the residual energy of the aggregate universes and you would expect indeed for the background radiation to be uniform and not a gradient.

Re:Seriously now

[vsprintf]

The universe is expanding at an accelerating rate not because of some dark matter but because of the gravitational attraction of other universes in the local vicinity of our own.

Other universes? Did someone redefine "universe" while I was at dinner?

Re:Seriously now

[buckpounders]

What makes the popcorn pop?

Re:Seriously now

[MightyMartian]

The universe is expanding at an accelerating rate not because of some dark matter but because of the gravitational attraction of other universes in the local vicinity of our own. sheeshh why do folks want to believe we are special with our own little private universe.

If other "universes" were gravitationally dragging our universe, then they and us would in fact be the same universe. The above idea has no resemblance of any kind to Big Bang cosmology, and in fact, is rather just a means of inserting an extra set of entities that have to be explained, thus further confusing the situation. The expansion of the universe is not related to any outside entity, because the universe is not expanding into some other space. It's space and everything in it that is expanding.

Re:Seriously now

[mOdQuArK!]

So, basically, you pull a theory out of your butt & modify it to match some qualitative things you know about.

The big question is: what kind of experiment can you propose to distinguish your theory from the other competing theories?

Re:Seriously now

[Mr. Arbusto]

He saw the end of Men in Black....Then again, those were Galaxys.

The true explanations for the Universal Expansion.

[Timmy D Programmer]

The mystery of why the universe is expanding more rapidly rather that slowing down is explained easily with the following theory:

'Our' Universe actually resides within a red rubber ball that belongs to gigantic beings, and it is currently being inflated

I simply fear they will begin playing dodgeball soon.

That Einstein...

[Omniscientist]

"Whether Einstein was right when he first introduced the cosmological constant, or whether he was right when he later refuted the idea will soon be tested by a new round of precision cosmological observations," Kolb said.

So either way, Einstein was right. Damn you Einstein!!!

Re:That Einstein...

[Oliver_Fisher]

If you want you can look at it this way, either way he was wrong... also

Re:That Einstein...

[Anonymous Coward]

Well duh. Why do think he's called Einstein, Einstein?

Fermilab Reports Dark Energy Not Needed

[secolactico]

Fermilab Reports Dark Energy Not Needed

Well, thank god! I was going crazy trying to find some.

Another attempt to deny things for the common man

[Anonymous Coward]

Sure, maybe those elitists at Fermilab don't need Dark Engery, but what about the rest of us?!

I demand they give us all equal access to Dark Energy for once and for all! Down with the scientific elites! Lets burn down the observatory so that this never happens again!

Why don't we just ADMIT IT?!

[Cryofan]

We don't know WHAT the fuck is going on when it comes to understanding the universe. We will, someday. But right now, we just need to assume that the universe will go on forever. That is the safest assumption to make, cuz all these wild assed guesses are just ruining science's credibility...

Why insist that the universe be "elegant"?

[G4from128k]

As far as I can tell (IANAP) so many of these scientific gnashings of teeth involve discrepancies between observations and intuitive notions for "how things should work." The human mind seems to really like simple laws and fixed constants. But what if the constants aren't and the "laws" are convoluted, contingent, or stochastic?

I'm not saying that we should not keep trying to create a self-consistent understanding of the universe, only that we be careful about foisting our human predilections for tidy explanations on to the developing theories and accumulating data.

Re:Why insist that the universe be "elegant"?

[the_2nd_coming]

because EVERYTHING that we have a pretty firm grasp on has a very elegant solution... and in Physics kludge is not good. Super-Symetry is what is looked for.

Re:Why insist that the universe be "elegant"?

[mcc]

The idea is that if two theories produce and predict the exact same results, the simpler one is to be preferred. If two theories produce and predict slightly different results, but the predictions only differ on matters which cannot be empirically tested, the simpler theory is to be preferred until such time as a way is found to empirically test which is more accurate.

This principle is often referred to as "Occam's Razor", as it is seen to be similar to an argument a 14th-century theologian named William of Ockham employed. His words, as Wikipedia quotes them, were something closer to "If two things are sufficient for the purpose of truth, it is superfluous to suppose another."

While this principle is technically not guaranteed to pick the "correct" theory, this is reasonable; would it be better, given two theories, to pick the one with more arbitrary complexity? Anyway, the only standard we have for "correct" is that it is consistent with evidence. Satisfying all collectable evidence is a worthwhile persuit in itself.

Re:Why insist that the universe be "elegant"?

[Jerf]

But what if the constants aren't and the "laws" are convoluted, contingent, or stochastic?

Studied QM much?

Less snarkily, the neat thing about physics-in-the-small is even the convoluted (brutally counter-intuitive) and stochastic laws we've developed are still fairly simple and elegant, and even though we aren't done there is no particular reason to believe the final iteration won't have elegance, either. The complexity comes from the sheer quantity of things; how many quarks are in your body, again?

(The elegance probably won't be comprehensible to the Man on the Street, though; physics is about 300 years ahead of him.)

Re:Why insist that the universe be "elegant"?

[radtea]

It isn't the universe that has to be elegant, but our theory of it. The reason why is that we aren't very smart, and theories with fewer free parameters are a lot easier for us to understand.

--Tom

Re:Why insist that the universe be "elegant"?

[mcc]

That's pretty good. I wish they'd modded you up instead of me.

Wish I understood Alpha

[purduephotog]

Saw this article a few days ago and it talked about Alpha- raised all sorts of questions for me (being a non-enlightened individual) such as

a) What are the implications if Alpha is 'decaying' with time?
b) What are the implications if alpha is variable with graviational mass?
c) If enough photons were gathered in one location, would they have a 'gravitational' effect... and would that affect any known 'constants'?

Tantalizing and interesting, but I know I lack the education to understand all of the ramifications.

Re:Wish I understood Alpha

[Anonymous Coward]

Wow, you are so dumb!!@ IDIOT!!!@1 dont EVEN waste my time with these stupid questions

I found it !

[Anonymous Coward]

sorry everyone, it was under my bed with my old socks

I believe in Dark Energy, and...

[LokieLizzy]

I'm not a scientist.

But I did stay at a Holiday Inn last night. And when the lights went out at midnight (power outage), I can assure you that there was more than a little energy going on in the room next door.

If there wasn't a Dark Force already...

[Nom du Keyboard]

If there wasn't a Dark Force already...

...George Lucas would invent it!

Re:If there wasn't a Dark Force already...

[Aranwe Haldaloke]

And 22 years later, he'd invent Dark Midichlorians.

DUH! expanding from the center!

[Anonymous Coward]

Um, if the universe is 28 Billion light years across, and is expanding outward from from a CENTRAL BIG BANG 14 Billion years ago... so what?

Wouldnt the light going in each direction from the central big bang go 14 Billion light years in all directions.

Said differently, wouldn't a sphere with a radius of 14 Billion light years have a diameter of 28 billion light years? Whats odd about that?

Re:DUH! expanding from the center!

[shredswithpiks]

what's odd: Ding! you hit the nail on the head... *if* the universe was made up of only light particles. We know (at least assume...) that normal objects with mass (planets, stars... you!) cannot travel at the speed of light. For the universe to have a diameter of 28billion light years, and have only existed for 14billion years, is indeed very strange. It suggests that the average speed of the universe as it expands has been the speed of light. But we already know this shouldn't be true because the universe is made up of more than just light. :D

Re:DUH! expanding from the center!

[Anonymous Coward]

See these FAQs. The size of the universe (as measured in "proper distance", which is what most people think of when they mean the "size" of the universe) is not linearly related to the age of the universe (e.g. it's not twice or half the age or anything).

Re:DUH! expanding from the center!

[Anonymous Coward]

I still don't get it. We -DO- know that c appears to be an absolute limit.

So, if the universe at its outer edges (ie the tiny percent out on the fringes traveling fastest away from the big bang) is travelling at, say .99999999 c, then the size of the universe and the size of the sphere are consistent at least to the accuracy of the measurments. (two significant digits in the grandparent example). And, the observable universe has the majority of its contents inside the sphere and not concentrated at the outer edges...

Now, consider: what if the universe at the moment is actually a sphere with a diameter of 27.95 billion light years and is 14.00 billion years old (now with improved accuracy of the measurments, nothing too wierd is required).

I'll go look those links over now.

The REAL Dark Force

[Polarism]

http://cyborgcentral.dynip.com/~pd/images/site/dar kforce.jpg

Is Dark Energy the New N-Ray?

[Anonymous Coward]

See http://www.rexresearch.com/blondlot/nrays.htm and http://www.spectrometer.org/path/nrays.html for details on N-Rays.

In 1903 a French professor of physics, Rene Blondlot thought he had found a new form of radiation. He and many others did experiments and published papers on these new rays until an American physicist, R.W. Wood, came by and proved that N-Rays did not exist. Some what like cold fusion, but in a less media crazy time.

It would be funny if dark energy was another example of too little data and too big a theory.

Re:Is Dark Energy the New N-Ray?

[Anonymous Coward]

N-rays were mistakenly thought to exist because of subjective experimenter bias, and were disproven when hard data were taken. Dark energy has already had hard data taken, and most recently the independent WMAP and Sloan Survey experiments gave high-precision data that were in beautiful agreement with each other, not to mention the original supernova data that kicked off the dark energy problem.

Re:Is Dark Energy the New N-Ray?

[Scott7477]

There was nothing wrong with the French guy; this is what science is all about. You identify a phenomenon, study it and put forth a theory to explain it. Other scientists review it and when further evidence is found your theory is either disproved or not.
The problem comes when scientists continue to promote their theories in the face of a preponderance of evidence which disproves their theory or propose theories which assume phenomena which have not yet been observed.
There is nothing particularly more bizarre about the concept of dark energy than concepts such as black holes or electromagnetic radiaton.

Surfs up!

[Anonymous Coward]

So the universe hangs ten???

Re:Nothing for you to see here, if you have an MBA

[swordfishBob]

We all know expansion doesn't require a cosmological consultant, don't we?

oh, it was "constant". Sorry.

Yeah, but...

[baldass_newbie]

...eddies in the space time continuum.

Re:Yeah, but...

[dr.newton]

He is, is he? :|

Re:Yeah, but...

[arodland]

He is. And I think that's his sofa.

Re:Yeah, but...

[Ultra64]

And this is his sofa, is it?

Re:Yeah, but...

[CableModemSniper]

And that's his couch then?

Did you ever get the feeling....

[blueforce]

sometimes, that these silly physicists just over-think everything?

Re:Did you ever get the feeling....

[rob_squared]

Physicists over-guess. We leave the over-thinking to philosophers.

Enjoy Fermilab's work while you can

[stox]

Their budget has been slashed almost in half. After all, low quality bombs are far more important than high quality science. In fact, spending on basic research is dropping at an alarming rate through all the national laboratories. This does not bode well for our future.

Re:Enjoy Fermilab's work while you can

[MustardMan]

Welcome to the era of government run by the conservative right. We can only hope that the supreme up-fucking that is privatization of social security will lead to a massive backlash and maybe we'll actually get some SANE people into office.

Re:Enjoy Fermilab's work while you can

[Anonymous Coward]

ya but who needs Fermilab with all their "fuzzy math" and such all you need is one hick cowboy with good ole common sense to tell whats what.

Re:Enjoy Fermilab's work while you can

[Anonymous Coward]

Yes indeed. There have been large cuts at BNL too. It's really sad.

Re:Enjoy Fermilab's work while you can

[tsotha]

In fact, spending on basic research is dropping at an alarming rate through all the national laboratories.

Do you have any real numbers to attach to this, or are you using the phrase "dropping at an alarming rate" to try to cover your lack of solid information? And don't tell me to use Google - you made the assertion; do your own research.

This does not bode well for our future.

I know this will be heresy here on slashdot, but perhaps you can explain why this is so. I've noticed a pretty distinct lack of "bang-for-the-buck" in this kind of research. Sure, there was nuclear power, but that was, what, 60 years ago? Fusion power seems to be permanently ensconced "30 years away". So tell me, what are my tax dollars doing for me at Fermilab, and how will this affect my life over the next 30 years (as I'm unlikely to live much longer than that)? I'm as curious as the next guy, but not "billions and billions" of dollars worth of curious.

Re:Enjoy Fermilab's work while you can

[stox]

Well, we could get into a very long and detailed discussion into the value of basic research. I'll point out just a few of the benefits we have received from Fermilab, and leave the rest to you.

1) Ever hear of a "computing farm"? I'm sure you have. The concept was pioneered at Fermilab.

2) Ask Bob Young, "Who made the most important confirmation of the value of Linux in the early days?" Couldn't be Fermilab, could it? ( Bob Young was one of the founders of RedHat, BTW. )

3) Who has done more basic research into superconductors? Who pioneered the use of superconductors? Fermilab.

4) How many lives have been saved through the use of radiation for treating cancer? Neutron therapy was pioneered at Fermilab.

5) Do you like American Buffalo? At one time, the only surviving herds were at Fermilab and Yellowstone. Fortunately, they have made a comeback.

6) Enjoy using the web? Fermilab was the third website on the planet, behind CERN and SLAC.

I'm sure I have missed a few, but I hope you get the point. We are lucky that our ancestors didn't take the same outlook as you. Some things need a horizon of lifetimes, not just your own. How long was the electron studied? Quantum theory? Radiation? Thankfully, many did, and have left us with a rich environment to live in. I hope the current generation, and those to follow, are wise enough to invest in the future with basic research.

As for my assertion that money devoted to basic research is dropping at a alarming rate, I will leave this as an exercise for the reader. The results of your studies will be quite enlightening, and quite possibly, terrifying.

Re:Enjoy Fermilab's work while you can

[tsotha]

Some of the stuff you pointed out was cool, some of it was pretty weak (the third website? Please. And server farms are a staightforward concept that was/is being developed at lots of different places). Not much there to do with super-theoretical physics. I'm all for spending money on medicine, superconductors (although I'm not sure the practical applications go much beyond MRIs in the near term), etc. But I question the value of spending lots of money on developing "brane" theory and trying to figure out why the universe is too massive.

I'm not a luddite - I do see value in basic research. But it's not a religion for me - as a taxpayer (and I do pay a hell of a lot of taxes) I want to be sure my tax dollars are spent efficiently. Even in physics there are lots of places to put research dollars (ITER, for example).

Also, the idea every dollar that goes to the military is a dollar lost to science is a logical falacy. We can afford to fund both if the payoff is clear. The scientific community has been doing a really lousy job selling the benefits of its research to the people that matter, and I can't figure out if the problem is the sales job or the product.

As for my assertion that money devoted to basic research is dropping at a alarming rate, I will leave this as an exercise for the reader. The results of your studies will be quite enlightening, and quite possibly, terrifying

That's what I thought - you're talking out your ass. Let me know when you can back it up. I'm not saying it isn't true, but it's clear you don't know any more about the overall budget than anybody else on slashdot.

Re:Enjoy Fermilab's work while you can

[hey!]

That's hick cowboy wannabe.

Re:Enjoy Fermilab's work while you can

[hey!]

How do you define "efficiently"? If "Efficiency" is the only value we have, and it is defined in purely economic terms, then I don't think basic science would be done at all. How can you put a value on knowledge?

You bring up the military, and this is a good example to illustrate my point. The military is notoriously inefficent. Because survival and victory come before efficiency. I'm not saying efficiency isn't important, but it's not the only consideration, and you can't wave it around like a magic wand to say everything you can't put a dollar figure on is "inefficient". At least not unless you are more consistent than most of us manage to be.

That's what I thought - you're talking out your ass. Let me know when you can back it up. I'm not saying it isn't true, but it's clear you don't know any more about the overall budget than anybody else on slashdot.

Well, according to the Feb 12, 2005 issue Science News, which I subscribe to, when adjusted for inflation the total science budget has been reduced by 1.4% in Fiscal Year 2006. I'm not sure, but I think this might be the second year in a row for a slight reduction or stagnant in the face of a increased focus on technological research relevant to national security. NASA got a budget boost in FY2006. Arguably this is necessary in the wake of the Columbia disaster, but basic science and technology programs at NASA are being cut.

Re:Enjoy Fermilab's work while you can

[feronti]

Some of the stuff you pointed out was cool, some of it was pretty weak (the third website? Please.

Actually, considering what the Internet was like at that time, it really is impressive. Were you even around when the Web was young? (To be fair, I wasn't exactly there at the start, either... but I was close...) It was pretty revolutionary, so anyone putting up a web site at the time was doing pioneering work.

And server farms are a staightforward concept that was/is being developed at lots of different places). Not much there to do with super-theoretical physics.

Except the ability to build better and better simulations of what happens at the subatomic level.

I'm all for spending money on medicine, superconductors (although I'm not sure the practical applications go much beyond MRIs in the near term), etc.

Superefficient power transmission? High-speed transportation? High speed communications?

But I question the value of spending lots of money on developing "brane" theory and trying to figure out why the universe is too massive.

Because chalk and blackboards are so expensive. You do realize that most of the research on brane theory is really just sitting around thinking about the equations right? Sure, there are experiments run to verify it, but most of the work is done on paper. Or on one of those compute farms you didn't think Fermilab was instrumental in designing. In addition, understanding things like "why the universe is too massive" is important, because it informs us about how the universe works, which potentially allows us to do things that were never done before. If Einstein hadn't thought about the photoelectric effect, we probably wouldn't have modern electronics. Yet at the time, it wasn't a problem with any kind of real application.

I'm not a luddite - I do see value in basic research. But it's not a religion for me - as a taxpayer (and I do pay a hell of a lot of taxes) I want to be sure my tax dollars are spent efficiently. Even in physics there are lots of places to put research dollars (ITER, for example).

But since we don't know what might become possible due to basic research, the most efficient use of basic research money really is a scattergun approach to follow as many paths as possible. Sure, some will be deadends, but there's no way of knowing which ones those are at the start. Simply because something may have a known application if successful, won't make it any more possible, so if you divert funds towards a project that you think is more practical and it turns out impossible, you've lost precious resources that could have been spent on something that would have returned some results you never thought of.

Also, the idea every dollar that goes to the military is a dollar lost to science is a logical falacy. We can afford to fund both if the payoff is clear.

And the payoff of blowing people up is? Besides which, even if we can fund both, how would reducing spending on the military not make more funding for science potentially available? Granted, we still might not choose to make that investment, but the argument that every dollar spent on blowing people up is a dollar lost to spending on more worthwhile causes including basic research is certainly valid.

The scientific community has been doing a really lousy job selling the benefits of its research to the people that matter, and I can't figure out if the problem is the sales job or the product.

I'm pretty sure it's the sales job. It's really hard to sell something that may not even be finished in your own lifetime to politicians who can't really see much further than their next election. The only real way to fix it is to get rid of the politicians. Unfortunately, there seems to be a lack of better options.

Re:Enjoy Fermilab's work while you can

[berbo]

stox (131684):

In fact, spending on basic research is dropping at an alarming rate through all the national laboratories.>

tsotha (720379) replies:

Do you have any real numbers to attach to this, or are you using the phrase "dropping at an alarming rate" to try to cover your lack of solid information? And don't tell me to use Google - you made the assertion; do your own research.

In other words, you're lazy and ignorant!

"R&D Funding Slows For 2006
President's budget proposes cuts in R&D spending at most agencies"

[Chemical and engineering News, February 14, 2005]

from the article: "research programs at the Department of Energy, except defense development projects, would be cut by $278 million, or 5%"

(whether you find that alarming is admittedly subjective)

Re:Enjoy Fermilab's work while you can

[tsotha]

In other words, you're lazy and ignorant!

I can't be an expert on everything. I just don't think it's unreasonable for people who make assertions to back them up. If I did fact checking for every post on slashdot I wouldn't be able to do anything else.

Was that supposed to be a link you posted?

Re:Enjoy Fermilab's work while you can

[tsotha]

Actually, considering what the Internet was like at that time, it really is impressive. Were you even around when the Web was young? (To be fair, I wasn't exactly there at the start, either... but I was close...) It was pretty revolutionary, so anyone putting up a web site at the time was doing pioneering work.

Heh. I was around when the internet was young. That was revolutionary. The web was nroff with hyperlinks.

Because chalk and blackboards are so expensive.

People are what cost the money. These guys aren't making minimum wage, and they do have expenses. True, it's not like building a supercollider, but I wouldn't call it cheap either.

But since we don't know what might become possible due to basic research, the most efficient use of basic research money really is a scattergun approach to follow as many paths as possible.

But how do we build a rational spending policy from that? How do we determine the right amount of money to spend when we have no way to know what the payoff could be? The other point I'd make is sometimes you get basic science when you're building practical things (like rockets and semiconductors).

And the payoff of blowing people up is?

That's overly simplistic. For one thing, the payoff for blowing people up could be better than the next thirty years of basic research. I wish we had blown up OBL after the Cole bombing. If somebody sneaks a nuke into NYC you'll wish we had blown him up beforehand.

If we can make better weapons to ensure more of our soldiers come back (from this conflict or the next) I'm all for it. Even if you don't agree with the current administration's foreign policy, would you at least be willing to concede a capable military is worth having?

Granted, we still might not choose to make that investment, but the argument that every dollar spent on blowing people up is a dollar lost to spending on more worthwhile causes including basic research is certainly valid.

If you're postulating a fixed budget, that's true. But that's not how it works - if the taxpayers think it's worthwhile, it'll get funded. If they don't taxes will get cut.

Re:Enjoy Fermilab's work while you can

[Anonymous Coward]

The guy who responded is right. Money put in to develop technology needed for devices such as accelerators usually returns as 4x because of new technology and knowledge that gets developed for experiment. And you learn something new about physics too. People in Europe are very smart and all have benefits from CERN (unlike G.W.Bush and his idiots).

Re:Nothing for you to see here, if you have an MBA

[Ohreally_factor]

Thanks for point that out. I was all set to register for cosmetology school, thinking it would be a growing field with lots of opportunities.

Twin universe model and negative energy particles

[Ummite]

http://www.jp-petit.com/science/metaphysique/geome trisation_antimatiere.PDF English .pdf. This guy actually need to be read. His model of the universe explain the "dark matter" problem very simply, and his computer simulation of this twin universe model (made 10 years ago) match the galaxy pattern we see, without esoteric explanations. If you can imagine the possibility of negative mass, you can understand easily why universe is expanding at a faster rate than predicted with current models. Read him (www.jp-petit.com, in french). And by the way, he was director of CNRS.

Inflation

[Knights who say 'INT]

is always and everywhere a monetary phenomenon.

Get the paper here

[Anonymous Coward]

The paper.

medium-ripples, nothing-no ripples

[Anonymous Coward]

so the big bang has an associated wavefunction?
hmmmmm
and just what cosmologic constants might be associated with it?
physics cranks want to know!

Interesting?

[MustardMan]

Seriously, how did this get a mod as Interesting? He bitches about the arrogance of humans thinking we are the center of everything, then is INSANELY arrogant in stating his own theory as if it were an indisputable fact, while providing NO evidence to support it.

The whole POINT of the term "dark energy" is to say "there's something funny here and we don't know what it is". I'd say that's one regulation shitload less arrogant than camel pilot's claim.

By the way, I'm far from a cosmologist, but the poster clearly has no grasp on the difference between dark matter and dark energy, and therefore has proven he doesn't have a clue what he's talking about.

Re:Interesting?

[multiplexo]

The whole POINT of the term "dark energy" is to say "there's something funny here and we don't know what it is". I'd say that's one regulation shitload less arrogant than camel pilot's claim.

Yeah, but calling it "dark energy" implies that we have some sort of understanding about it, which we don't, other than something is apparently causing the universe to expand. Perhaps scientists should start calling this force/material "whatthefuckoverium?", or if a particle interaction is involved describe the particles as "whoknowsitrons?"

In other news...

[sPaKr]

The producers of Startrek Enterprise gave themselves concusions from repeated blows of their heads to their desks. One producer cried "Ripples in space time explain the universe, WHY COULDNT WE GET THESE GUYS AS WRITERS!'

Re:In other news...

[ari_j]

How about

COMES NOW the plaintiffs, who allege:

1. Plaintiffs are producers of the TV show Star Trek: Enterprise.
2. Defendants are the class of all scientists in the world.
3. Defendants stole and used as their own a plot device from the Star Trek: Enterprise finale; namely the idea that ripples in space-time explain the universe.
4. Because of defendants' act of plagiarism as described in paragraph 3, plaintiffs suffered gazillions of dollars of damages.

WHEREFORE plaintiffs demand that the court give them gazillions of dollars from the scientists, and rename the universe "Space: The Final Frontier."

Re:In other news...

[SharkJumper]

Discuss amongst yourselves:
The SF show, Star Trek, a show that tries to make its techno-babble sound serious, comes off as imminently mockable because of a lack of scientific grounding among its writers and producers. On the other hand, Futurama, a SF cartoon whose science is meant to sound funny, actually has some serious math and science due to the backgrounds of the executive producer and some of the writers.

SharkJumper

Re:Dark Energy

[Anonymous Coward]

No, this is not correct. The cosmological constant is merely the simplest model of dark energy. There are other models including dynamical fields, e.g. quintessence. They can sort of act like a time-varying "effective" cosmological constant, but they're not a true cosmological constant term.

Fermilab...or Four From Fermilab?

[luna69]

Shouldn't this read "Four scientists at Fermilab report..." rather than "Fermilab reports..."?

Fermilab is a big organization. Saying that "Ferilab reports" implies that the whole organization reports this, and I'm absolutely positive that there are many people within Fermilab who would dispute these results/conjectures/hypotheses.

Imagine someone reading something one of us says in a comment on /., and the NYT reporting that "Slashdot says that..."

Re:Fermilab...or Four From Fermilab?

[dotmax]

FERMILAB. It is an official Fermi press release. Read the press release. You are stupid.

Re:Fermilab...or Four From Fermilab?

[Anonymous Coward]

Ahem. It is you, sir, who are stupid. Fermilab issues press releases about noteworthy publications by individual Fermilab employees, just like universities issue press releases about their researchers' work. This is in no way an official endorsement by all members of Fermilab, just like a press release by a university is not endorsed by all university faculty, or even all departmental faculty. What happens is, individual scientists are asked to send any work that they think should be publicized into the organizational PR department, which works up a press release on it. The rest of the institution is not consulted.

Re:Fermilab...or Four From Fermilab?

[dotmax]

WRONG. It is an official laboratory statement, from the official mouth of fermilab, ergo it is the vetted, offical Word from Fermilab, the Insitution.

Whether the rest of Fermilab is consulted is irrelevant. If the Public Affairs dept issues a statement saying chocolit ice cream is the seventh force, it is by definition the official institutional position. "Official endorsement" by "all members of Fermilab" is such a stunningly idiotic test as to be sub-idiotic.

If you care to discuss the matter further, i will be in the Main Control Room until midnight.

Re:Fermilab...or Four From Fermilab?

[luna69]

Please see the post below, in which the responder quite correctly points out the obvious conclusion to your observations: you are the one who lacks perceptive ability. Moreover, you didn't bother to read the article, which clearly states that "An original solution to this puzzle...was put forward BY FOUR theoretical physicists".

Re:Fermilab...or Four From Fermilab?

[dotmax]

PSSST! (Only one is a Fermilab guy!) Let's try it again, because it was too subtle. "A Fermilab press release reports". Fermilab's official position is that Rocky and Three other people (from canada and italy) submitted a Phys. Rev. paper. Fermilab reported this submittal. That's their official position. wanna go 0 for four?

Re:Fermilab...or Four From Fermilab?

[Anonymous Coward]

I suggest you talk to FNAL's PR department if you're this fucking clueless.

Yes, it would be idiotic to submit a press release for endorsement by all members of Fermilab. But that is precisely what would be required for the press release to reflect anything more than the views of these four authors. For that matter, press releases are not vetted by any kind of official committee that decides what the official institutional position on dark energy is. They're just handed off to PR flacks to publish and distribute. Another group at FNAL could come up with a completely alternate dark energy theory tomorrow, and they'd get a press released issued too. Press releases are simply NOT any kind of reflection of the scientific opinion of an institution, they are nothing more than the dissemination of work done at that institution.

By the way, I'm upgrading you from "stupid" to "fucking dumbass". HTH, HAND.

Re:Fermilab...or Four From Fermilab?

[Anonymous Coward]

Not only did nothing you said contradict the previous poster, nothing you said supports your point, either. Yes, "A Fermilab press release reports". Your idiocy is in believing that Fermilab issuing a press release is somehow equivalent to Fermilab taking an official stance on the truth or even scientific merit of the work.

Re:Fermilab...or Four From Fermilab?

[dotmax]

you mean... like the top quark?? .max

Re:Fermilab...or Four From Fermilab?

[Anonymous Coward]

Your dumbassedness persists. Amazing.

Let me spell this out once again: a press release reports results that researchers at the institution have reported. That could be a claim to the discovery of the top quark, a claim to resolving the dark energy question without using a cosmological constant, or any other result published by researchers who work there. Once again, that does not mean that the Institution Officially Endorses the result. In the top quark case, probably most people at Fermilab did. (There have been cases at other institution of rival groups not agreeing with each other, though.) In this case, it's far more speculative. In any case, you are sadly deluded about the nature of press releases.

Re:Fermilab...or Four From Fermilab?

[dotmax]

you're right. i completely misread the orginal post. my bad.

Re:Fermilab...or Four From Fermilab?

[Anonymous Coward]

Wow, I think you just restored my faith in humanity. If I'd been defending a misinterpreted point, I'd have slunk off never to be heard from again.

Re:Fermilab...or Four From Fermilab?

[dotmax]

My pleasure. BTW, and you can be the first to know -- while i was flaming, we set a new "world" record for antimatter production of 16.2e10 antiprotons/hour http://www-bd.fnal.gov/notifyservlet/www. Not that anyone else around here will see it.

What if Dark Energy Wasn't Required

[nimblebrain]

There's a decent amount of evidence that has been mounting over the past few years that a large component of redshift is in fact intrinsic, i.e. not attributed to the Doppler effect.

In some ways, it seems related to the much-glossed-over "K Effect" of a few decades ago, where it was found that bright, bright blue stars seemed to be systematically redshifted.

Researchers like M. B. Bell are of the opinion that the intrinsic redshifts are superimposed on a Big Bang flow (reducing the actual velocity we should be measuring). Others, like Arp, believe that the Hubble Flow is an illusion, and that the universe is actually relatively static once you take away the intrinsic redshifts.

David Russell's paper that just came out supports either view, and shows that other explanations (like Tully-Fisher Relationship errors or rotational velocities) are far too small to account for the large discrepancies.

(Some more hubbub on the topic.)

In either case, intrinsic redshifts will take a lot of pressure off researchers to find 'dark energy', because the discrepancies of speed/distance are much reduced.

Then, perhaps, we can stop looking for something that isn't there? :)

Re:What if Dark Energy Wasn't Required

[Anonymous Coward]

I don't know about the other guys, but it's widely accepted in the astronomical community that Arp was a good scientist who has descended into crankdom, due to shoddy use of statistics.

Re:What if Dark Energy Wasn't Required

[Creepy Crawler]

No wonder I like Giving #4 and #132 ;-D

Re:What if Dark Energy Wasn't Required

[TerrierTribe]

Scientific American has a recent article covering much of this, including a nice sidebar explaining why redshift is not doppler related.

Re:What if Dark Energy Wasn't Required

[TerrierTribe]

oops, forgot the link: SCIAM.

Re:What if Dark Energy Wasn't Required

[nimblebrain]

That's the summary of the story that's been put together so far :)

The redshift they describe is 'cosmological redshift'. It is true that it would be technically incorrect to call it a Doppler redshift if the currently-held accelerating universe view is actually true.

There are Doppler redshifts on top of this as well - rotations and movement add to or subtract from the cosmological redshift.

What the papers I quote have been finding is that cosmological redshift (whether Doppler or not) isn't enough.

Intrinsic redshifts are statistically important. They do not, however, get rid of the cosmological component.

The current 'accepted' value of the Hubble Constant, which reflects the age of the universe, is 72 km/s/Mpc, giving us an age of about 13 billion years.

Taking the instrinic redshift from that gives us a Hubble Constant of 50-60 km/s/Mpc, which gives us an age of about 18 billion years, so that theorists might have time to deal with the 'vegetable soup' phenomenon, to quote a sound bite.

(Looking back to 1-2 billion years after the Big Bang, the universe still doesn't look very young. Of course, the revised age will also alter back the ages of some of the objects.)

There's some reason to believe that even the remaining cosmological component may not actually represent expansion, and it was presented in one of Edwin Hubble's later lectures, "The Observational Approach to Cosmology".

The premise, basically, is that a redshift would give a corresponding decrease in photon density, if due to expansion, but it doesn't.

We'll see what happens over the next few years, though :)

Thanks for the link!

Re:What if Dark Energy Wasn't Required

[galva]

Maybe the whole FRW cosmological model is wrong. It assumes the universe is homogeoeous. Here, someone argues that this assumption may be wrong:

(at http://arxiv.org/abs/astro-ph/0503715 sorry, the preview button makes me think the URL: isn't working)

ahref=http://arxiv.org/abs/astro-ph/0503715http:// arxiv.org/abs/astro-ph/0503715>

Abstract: It is widely believed that the assumption of homogeneity is a good zero{\it th} order approximation for the expansion of our Universe. We analyze the correction due to subhorizon inhomogeneous gravitational fields. While at early times this contribution (which may act as a negative pressure component) is perturbatively subdominant, we show that the perturbative series is likely to diverge at redshift of order 1, due to the growth of perturbations. So, the homogeneous Friedmann equation can not be trusted at late times. We suggest that the puzzling observations of a present acceleration of the Universe, may just be due to the unjustified use of the Friedmann equation and not to the presence of a Dark Energy component. This would completely solve the coincidence problem.

Here is the original paper

[leoval]

For anyone that can actually understand it click here (in pdf format)

Re:Here is the original paper

[Anonymous Coward]

A better link, to the abstract plus PDF plus links to other papers written by the authors plus the references cited:

Scientists aren't the only clueless ones here

[foreverdisillusioned]

Can't we just admit we don't have a freakin' clue and move along?

Move along to what? Above all else, science is supposed to try to explain these mysteries. To give up because we don't have a (seemingly) elegant or simple explanation is, well, the anthesis of the scientific method. You've got to come up with a theory. Maybe it sounds good, and maybe it doesn't--the only real question is, does it explain the phenomenon being observed?

If I knew Einstein back in 1905, I would've told him he needed to lay off the crack pipe. "Matter bending space? Relative velocity creating differing timeframes? Dude, what a fantasy, what a KLUDGE! You can't just go ripping apart some of the basic assumptions of science just because you want Maxwell's and Newton's ideas to play nicely together."

...but he was right. He took a stab in the dark, figured out an explanation that worked (even though it sounded insane from a "common sense" point of view), and the evidence proved him right. Time and space are relative--we know this for a fact now, because other scientists set out to prove (or disprove) Einstein's crazy ideas. We're not so sure about Dark Energy/inflation ripples/mystical tomatoes, and hell, we might never know for sure, but it's obvious that SOMETHING is going on here, and I for one am glad that the scientists of today are coming up with these all of these cheesy, crazy explanations.

The difference between dark matter and dark energy

[Anonymous Coward]

Dark matter is, well, matter. Some of it is probably ordinary baryonic matter that's cold, like brown dwarves and such; some of it is probably weakly-interacting elementary particles. Dark matter, like all matter, produces an attractive gravitational force.

Dark energy is not what we think of as "matter" at all. One of its key physical properties is that, unlike matter, it has negative pressure. This is what causes the expansion of the universe to accelerate: in general relativity, not only mass-energy but pressure (and other things, like stress/strain) gravitate. Positive pressure is attractive; negative pressure is repulsive.

(Incidentally, this is why black holes form when a star undergoes gravitational collapse. You might think that it would collapse a bit and then the collapse would halt, as the star's internal pressure resists further collapse. But for a sufficiently massive collapsing star, the internal pressure builds up so strongly that its gravitational attraction outweighs the force of its repulsion, and further increases in pressure actually hasten the collapse instead of slowing or halting it.)

There have been various theories of what dark energy is; the simplest is that it's Einstein's cosmological constant, a term Einstein introduced into general relativity in order to have a static universe (a repulsion that exactly balanced the gravitational attraction of the matter in the universe, so space neither expands or contracts). Einstein retracted this idea when it was shown that space is expanding, but it was resurrected to explain how the expansion could accelerate.

It's possible to rewrite Einstein's field equation to put the cosmological term, which is ordinarily on the left-hand "curvature" side of the equation, onto the right-hand "source of gravity" side. In that case, it's interpreted as the mass-energy/pressure/etc. contributed by the vacuum itself (which is possible in quantum field theory, with the zero-point energy). Unfortunately, quantum field theory predicts the wrong value for this by over 100 orders of magnitude, leading to the "cosmological constant problem". Other approaches to dark energy involve dynamical quantum fields -- which can be sort of treated as a time-varying cosmological constant, although there can be additional differences -- with exotic properties, like negative pressure.

Wikipedia on dark matter and dark energy.

Did anyone else...

[Anonymous Coward]

read infineon labs instead Fermilab?

10-4 there...... .......roger.

Re:The difference between dark matter and dark ene

[Anonymous Coward]

See also Ned Wright's cosmological constant FAQ.

Physics data and theories - how suspect are they?

[CrackHappy]

I had not seen anyone raise this point, so I wanted to bring it up.

With the vast amount of data at physicists fingertips, and many theories to test against this data set, how confident are physicists that the theories on which they base other theories are in fact true?

How can we be sure that the data we receive from galaxies 10 billion light years away has not been diluted or compromised in a way we could not detect? If that happens, would not our theories then also be diluted or compromised and thus destabilize whole sections of theory?

I ask these questions because of my observations about physics and theorizations in general. There are of course some things that locally we can easily prove or disprove, but when you start using data that is so difficult to reliably receive from extremely distant points in the universe, I just worry how much time and effort goes into the wrong idea.

Don't get me wrong, physicists are doing a GREAT job and have benefitted the world tremendously. I hope this work does not stop and indeed increases!

What are you talking about?

[Quiet_Desperation]

Huh?

Just as an example, the HEP program at FermiLab is budgeted at $737 million for FY 2005. That's an increase over 2004 of a few million dollars. Science spending is up all over the place.

Re:What are you talking about?

[stox]

I'd sure like to see where you are getting your numbers, The budget for FY2005 is $308M.

I find their lack of faith disturbing.

[spirit_fingers]

Let me show you the power of Dark Energy! [unleashes Sith choke hold on fermilab scientist]

Re:Physics data and theories - how suspect are the

[Anonymous Coward]

You can never rule out the existence of a phenomenon that's screwing things up in an undetectable way. Indeed, if it has no detectable effect, who cares? But you can rule out alternatives that have side effects. For instance, you could postulate that the redshifting of light from distant galaxies is not due to recession in an expanding universe, but is instead due to some other mechanism which causes light to lose energy as it travels ("tired light"). But there are many ways that various specific tired-light models fail to be consistent with other observations. If two explanations give the same predictions for all observations that we can perform, we can never tell the difference between them, but often that's not the case, and we can rule out alternatives.

Warp drive

[Anonymous Coward]

So if you can induce (local) faster-than-light ripples and you (matter) stay fixed relative to the ripples (like surfing), have you just invented faster-than-light travel?

I suppose that would require some massive amounts of energy...

Just a stupid question from a biologist who knows little about relativity.

Re:Warp drive

[Anonymous Coward]

Yes, that's one method of FTL travel. The Alcubierre warp drive works on that principle. Unfortunately, it requires negative energy to work, and there doesn't appear to be any of that in our universe. (Ok, you can get into discussions of the Casimir effect, so maybe it's barely possible... but will require either very high energies or energy densities.)

Re:Warp drive

[Anonymous Coward]

Hey, thanks, that's interesting reading !

Newton's Cosmological Constant?

[nikremt]

Maybe somebody can help me out here.

I am looking at the Fermilab press release and it states, "When in 1929 Edwin Hubble proved that the universe is in fact expanding, Einstein repudiated his cosmological constant, calling it 'the greatest blunder of my life.'"

I may be mistaken here, but I thought that Einstein's Cosmological Constant was introduced to modify His theory so that it would not predict an expansion in the Universe? Then that would explain why the article from Fermilab says that He later repudiated His Cosmological Constant after Edwin Hubble verified the expansion experimentally.

After reading it over and over again, I still get from the article that Einstein's Cosmological Constant was added to the theory to explain the expansion. But didn't His theory already explain expansion? And if so, why would He "repudiate" something that was experimentally verified a few years later by Edwin Hubble? Then if His theory already predicted expansion, then the only purpose of introducing the Cosmological Constant that explains expansion would be to enhance the prediction in expansion rate, would it not?

Is there a contradiction in the article? Am I missing something?

Re:Newton's Cosmological Constant?

[nikremt]

Okay, Maybe I am an idiot... I meant Einstein's Cosmological Constant, NOT Newton's Cosmological Constant. Please still take my question seriously.

I used the Preview button, Honest!

Re:Newton's Cosmological Constant?

[Anonymous Coward]

When Einstein was first working out cosmological predictions, it was not yet known that the universe was expanding. Einstein philosophically believed that the universe was static. Hubble's observations did not experimentally verify an accelerating expansion (which is what the cosmological constant is needed for); that was only discovered circa 1998. Einstein's cosmological constant, mostly rejected since Hubble, was brought back, because it can not only explain a lack of expansion (in the form of a static universe, although that solution is unstable and therefore implausible), but it can also explain an accelerating expansion.

Re:Newton's Cosmological Constant?

[Anonymous Coward]

So, as one of the above responses notes, Einstein added a Cosmological Constant to cancel the effect of the expansion his theory was predicting.

He removed it when Hubble's observations found the universe to be expanding.

Later, via observation, it was noted that the expansion is accelerating, rather than decelerating.

If you reintroduce a Cosmological Constant, with a -different value- than Einstein originally introduced, you can explain the acceleration of the expansion.

Make sense? constant (Original Value) = cancels out expansion, static universe; No constant = universe decelerating expansion; constant with new value (different than original) = universe with accelerating expansion.

I could be wrong, but that's how I understand it.

Re:Newton's Cosmological Constant?

[Lord Crc]

After reading it over and over again, I still get from the article that Einstein's Cosmological Constant was added to the theory to explain the expansion. But didn't His theory already explain expansion? And if so, why would He "repudiate" something that was experimentally verified a few years later by Edwin Hubble? Then if His theory already predicted expansion, then the only purpose of introducing the Cosmological Constant that explains expansion would be to enhance the prediction in expansion rate, would it not?

Yes, Enstein saw that his model expanded, and added the constant to compensate for the expansion. This was because at that time, the current view was that the universe was static.

However, from what I've gathered, what we've been discovering in recent time is that the expansion is accelerating, and that this acceleration could be explained by re-introducing Einstein's constant. Here's a quote I found: "Unlike Einstein's famous fudge factor, the cosmological constant in its present incarnation doesn't delicately (and artificially) balance gravity in order to maintain a static universe; instead, it has "negative pressure" that causes expansion to accelerate."

Of course I could be very wrong on the last part, I just enjoy reading about these things. Exciting times! :)

Re:Newton's Cosmological Constant?

[gibson042]

I am looking at the Fermilab press release and it states, "When in 1929 Edwin Hubble proved that the universe is in fact expanding, Einstein repudiated his cosmological constant, calling it 'the greatest blunder of my life.'"

I may be mistaken here, but I thought that Einstein's Cosmological Constant was introduced to modify His theory so that it would not predict an expansion in the Universe? Then that would explain why the article from Fermilab says that He later repudiated His Cosmological Constant after Edwin Hubble verified the expansion experimentally.

Your understanding is close, but a little off. At the time Einstein was formulating General Relativity, he (and just about everyone else) believed in a static universe. But this was an impossible state in his new system; the universe had to be either expanding at a constantly decreasing rate or contracting at a constantly increasing rate. Any "static" universe would begin contracting immediately. Seeing this, Einstein added a (positive) cosmological constant to prevent the contraction, with the thought that its value would perfectly balance out gravity and allow for an unchanging cosmos.

Later, when Hubble found that the universe was actually expanding, Einstein regretted the decision. From that time until 1998, the value of the constant appeared to be zero and thus its inclusion in General Relativity inconsequential.

So...

[John Bokma]

Can I have it? Can I, Can I?

Re:Physics data and theories - how suspect are the

[Y2]

How can we be sure that the data we receive from galaxies 10 billion light years away has not been diluted or compromised in a way we could not detect?

I don't know what you're thinking when you say "data ... diluted or compromised," but it's a lot more difficult than you may realize to come up with a scheme which has something funky happpening over long distances of space without us being able to detect side-effects.

Re:Physics data and theories - how suspect are the

[Anonymous Coward]

And yet that is exactly what this report is saying happened....

In Soviet Russia...

[Anonymous Coward]

the Fermilab reports you!

Laws of the univers

[pr0f3550r]

I guess this proves that dark energy cannot be created nor destroyed...but can change.

Summary

[Anonymous Coward]

[1]
When his own Theory of General Relativity clearly showed that the universe should expand or contract, Einstein chose to introduce a new ingredient into his theory.
[2]
His "cosmological constant" represented a mass density of empty space that drove the universe to expand at an ever-increasing rate.
[3]
"We realized that you simply need to add this new key ingredient, the ripples of spacetime generated during the epoch of inflation, to Einstein's General Relativity to explain why the universe is accelerating today," Riotto says

Re:Summary

[Anonymous Coward]

Your summary incorrectly implies that the "new ingredient" Riotto is talking about is the introduction of a cosmological constant. In fact, the claimed "new ingredient" is a heretofore neglected implication of inflation, and Einstein's cosmological constant is not needed. (Or so they claim.)

Re:Fermilab employee chiming in

[heyitsme]

Their budget has been slashed almost in half. After all, low quality bombs are far more important than high quality science. In fact, spending on basic research is dropping at an alarming rate through all the national laboratories. This does not bode well for our future.

This isn't quite true. DOE's funding for High Energy Physics Programs (basically, Fermilab and SLAC) is down 3.1%, or $22.5 million, from $736.4 million to $713.9 million. (I couldn't find out exactly how much Fermilab lost from those cuts, but I recall seeing a figure of about a 4% decrease w/inflation, which is pretty consistent over the past 5 years) Furthermore, run times of the accelerators would be increased over FY 2005 levels at the Fermilab Tevatron (6% more operating hours) and SLAC (54% more hours).

Along with the budget cuts, the BTeV project at Fermilab was canceled. With HEP experiments at SLAC and Brookhaven going offline in a couple of years, Fermilab will soon be the only HEP lab in the nation. Currently the CDF/D0 experiments (the two main detectors) on the Tevatron are scheduled to run until 2009 or 2010. And MINOS/NuMI will run at least that long as well.

Fermilab is going through a 5% workforce reduction, voluntary at first... The saving grace for Fermilab right now will come in the form of the International Linear Collider, the Next Big Thing(tm) in HEP. More info at http://www.interactions.org/linearcollider/ and http://ilc.fnal.gov

More insider info upon request, heh.

Re:Fermilab employee chiming in

[stox]

I was lead to believe that FY2006 was being cut by $107M, and the cancellation of BTeV and voluntary force reduction was done in anticipation of this. I was very sad to hear that BTeV was cancelled, there was some damn good science that could have come out of it. Good to see that MINOS is rocking, though.

Enjoy your time at Fermi, it is a great place to work in.

preprint

[bcrowell]

The preprint is here.

Re:preprint

[Anonymous Coward]

We know.

Dark force not needed.....think and look again!

[Anonymous Coward]

Those who would discard dark energy in order to make their math 'simpler' might ask themselves: "What caused the inflation in the first place?"! Ripples, inflation implying change in the fabric of space, all require some energy force as the engine of change.

Re:Dark force not needed.....think and look again!

[Anonymous Coward]

Uh, hello!

They aren't saying that there is NO energy! Just that there may not be a need for any MORE energy that that which we already know about and observe.

not needed?!

[tverbeek]

So much for the dark-matter factory I spent so much money building. I just hope I can get my current inventory liquidated on eBay.

And they call me crazy?

[Anonymous Coward]

People diss me for believing in God. They say "How can you believe in something that you can't see? How can you believe without proof?"
I point to the many miracles performed over the ages, the miraculous cures, the signs at Lourdes, at Fatima, at Guadalupe, etc.
But my unbelieving friends just keep saying that it can't be proof of God cause, at heart we don't want it to be and besides it's not scientific.

Then along comes an argument like this. Gee we science types have data that all our science says doesn't make sense, so to explain it we'll postulate unexplained varying physical sates for the Universe that start for no reason we can nail down and then end for no particular reason we can give (Expansion), invisible energy that no one seems able to find (Dark Matter), or unprovable ripples that just happen to be beyond our ability to find or prove (Cosmic Irregularity Theory?).
And our evidence for this? Well it makes our math look good (just as long as you use our equations to do the math with, anyway)

So which of us believes in things that they can't prove again? I think I lost track of who was being sillier then whom in that one.

Re:And they call me crazy?

[Anonymous Coward]

Because an old white guy with a beard snapping all of creation into being with his fingers makes *SO* much more sense!

Re:And they call me crazy?

[Anonymous Coward]

Theory == testable / provable
Religion == not testable / not provable

Isn't it odd that science has actually *proven* a lot of stuff in the last 2,000 or so years while religion has yet to even come up with something better than "well... this god guy just kinda *willed* it to be so it was. That's all the proof we need."

Grow up. Make believe time is over.

Re:And they call me crazy?

[Anonymous Coward]

Dark Matter, Dark Energy, ripples, etc. are postulates. Based on thesr postulates, predictions will be made and tested. If the tests do not validate the predictions, the postulates will be thrown out.

Creationists invoke God and then say 'God is the answer, we can stop thinking about it now, end of story, and oh, there's no way it's at all wrong'.

See, scientists say 'Dark Matter -might- be the reason, Dark Energy -might- be the reason' ... but they do not say 'Dark Matter -is- the reason, and no one else should look for any other, even though there's no proof'.

So, yes, you're the one believing in things you can't prove. The rest of us are waiting for indications that dark matter, dark energy, ripples , etc, are or are not consistent with reality.

Re:And they call me crazy?

[mr100percent]

Who says God works by magic? He has power, but we do not understand it, the same way you and I don't understand this big bang/dark matter/dark energy conundrum. Depending on who you ask, some religions have proven and forecasted a lot of stuff.

What would it take to prove the existence of God from nature? Maybe something in nature that doesn't appear possible or make sense in nature, yet exists anyway? Wouldn't this Horizon problem be something to point out? What about all those cosmic rays that impossibly are higher than the Greisen-Zatsepin-Kuzmin limit? It just doesn't make sense, there has to be something creating that sort of order and miracles from chaos.

Re:And they call me crazy?

[Anonymous Coward]

"Those who cavalierly reject The Theory of Evolution, as not supported by the facts seem quite to forget that their own theory is supported by no facts at all." - Herbert Spencer. While this quote speaks of evolution, it could easily be applied to this discussion. It makes no sense to say, oh well, science does not yet explain everything so therefore something that is completely unprovable is the most reasonable explaination.

Science changes to fit the facts and as our understanding of the world changes, religion tends to hang on to something because someone wrote it in a book along time ago. Some go so far to as to take everything in these books say as the literal truth, even thought there are things in them that are provably wrong.

While science may not have all the answers and may never, it is probably closer to being on the right track. Religion claims to have all the answers but seldom can back it up.

Re:And they call me crazy?

[spauldo]

Christianity != science

In science, you have to back up your theories with evidence, and all your work is under constant peer review. Someone might come out tomorrow proving that your work is incorrect, and have a better theory.

In Christianity, you accept things based on faith. Proof doesn't enter the equation - it can't, since the whole point of the religion is to have faith. Having faith despite proof is what the game's all about.

They're not related! They have nothing in common!

Why the hell do people bring this crap up? Do christians believe they'll convert people by it? Are non-christians just wanting to be assholes? What the hell?

Re:And they call me crazy?

[dalyraptor]

No, something that does not appear possible or make sense in nature does not prove that god exists. You cannot put everything that you do not understand down to god, jesus christ!

Re:And they call me crazy?

[Anonymous Coward]

Not all of us who believe in God are Creationists. Many of us find the them embarassing and wish they would shut up and go away. I believe in both God an Darwin and don't see any contradiction there at all.

Re:And they call me crazy?

[Glock27]

Then along comes an argument like this. Gee we science types have data that all our science says doesn't make sense, so to explain it we'll postulate unexplained varying physical sates for the Universe that start for no reason we can nail down and then end for no particular reason we can give (Expansion), invisible energy that no one seems able to find (Dark Matter), or unprovable ripples that just happen to be beyond our ability to find or prove (Cosmic Irregularity Theory?). And our evidence for this? Well it makes our math look good (just as long as you use our equations to do the math with, anyway)

What you're missing is that science has theories that make predictions about observable things in the real world.

General Relativity, for instance, led to predictions of 1) longer particle decay times for moving subatomic particles, 2) different orbital period for Mercury than Newtonian mechanics predicted and 3) bending of starlight due to intervening gravitational fields. There are quite famous observations confirming these predictions.

Similarly, there are quite convincing observations that lend support to the Big Bang theory. Cosmic backround radiation measurements, observed Hubble expansion and observations of galactic evolution as we look further away (further into the past) come to mind as examples.

That is the difference between religion and science. Science attempts to verify its theories with observed phenomena and experiments. Religion accepts its theories based on blind faith.

All that said, there is nothing incompatible between science and religion really, as long as your religion doesn't dogmatically insist its wisdom about the real world subsumes observed scientific knowledge (the big trap into which some Christian sects seem to have fallen). In fact, I would argue that quantum mechanics provides an interesting "out" for religion - quantum randomness versus "Gods will". After all, quantum randomness is neither knowable or predictable for us, but it might be exactly enacting Gods will...

I've often wondered why Einstein said "God would never play dice with the Universe". Perhaps Gods dice are loaded. :-)

Re:And they call me crazy?

[Mr. Slippery]

What would it take to prove the existence of God from nature?

An artist's signature. Surely if the universe were created by some being, it would be very simple to such a being to provide obvious evidence of this.

Maybe something in nature that doesn't appear possible or make sense in nature, yet exists anyway?

If it doesn't make sense under our theories, then we change our theories. When the orbit of Mercury didn't obey Newton's predictions, we didn't say, "ooops, must be divine intervention!"; we posited new theories, until Einstein came up with general relativity to explain it.

It just doesn't make sense, there has to be something creating that sort of order and miracles from chaos.

Then there would have to be something creating that creator, since that creator has even more order. And something creating that creator-creator. And something creating that creator-creator-creator. And so on. Sorry, but positing a creator-being doesn't explain anything.

Re:And they call me crazy?

[Anonymous Coward]

An artist's signature. Surely if the universe were created by some being, it would be very simple to such a being to provide obvious evidence of this.

That would be simple for an omnipotent being, but perhaps not what said being would want. If there was indisputable evidence for a Creator, that would reduce the moral value of believing in one and even such concepts like Free Wil.

To put it another way, most moral constructs (religious or otherwise), are based on the concept of responsibility for or actions. This responsibility comes from the assumption we have choices on how to act, there might be practical limitations on our actions but we always have some options available. However, some would argue that "good" done out of coersion or the fear of punishment isn't really good, in the moral sense. If God can be objectively proven to exist what is "good" about believing in God? Or if God can be proven to exist and has an equally provable set of rules he wants us to follow, is there really any morality in following these divine rules?

Maybe it is the fact that belief in God is one choice out of other options, that allows it to have any moral worth.

If it doesn't make sense under our theories, then we change our theories. When the orbit of Mercury didn't obey Newton's predictions, we didn't say, "ooops, must be divine intervention!"; we posited new theories, until Einstein came up with general relativity to explain it.

I've never been a believe of "God in the gaps" either. However, I don't think it is beyond the capability for an omnipotent being to make a universe that has "laws" that control what goes on in it, and that eventually produces intelligent beings that are able to incrementally build and refine an understanding of these "laws".

Then there would have to be something creating that creator, since that creator has even more order. And something creating that creator-creator. And something creating that creator-creator-creator. And so on. Sorry, but positing a creator-being doesn't explain anything.

What we understand as time and causality can only be proven in our own universe. You can theorize that if there is any "thing" outside our universe the rules are the same, but it is an equally valid theory that they are not. If in this "metaverse" the rules are different than there might be a being/intelligence/will that had no beginning or end, it always was and always will be. In that case your arguement is meaningless.

Re:And they call me crazy?

[Anonymous Coward]

Firstly one must define God, if such a definition includes the concept of the supernatural then it must also have a set of criteria for what is natural and for when a mystery is promoted to supernatural status.

My Point: The inarticulate nature of the intuitive concept of God should keep God out of scientific discussions, science has it's own catch all inbox for spooky action and we call it nature.

Re:And they call me crazy?

[hesiod]

> Do christians believe they'll convert people by it? Are non-christians just wanting to be assholes?

You have that backward. The Xtians who say that kind of stupid stuff just want to feel superior to others, so they basically lay claim to their own divinity. They are the assholes. After all, there is no other good explanation I can find why they think they should get into heaven -- despite their verbal attacks, warmongering, and generally unchristian living -- yet a pacifistic Buddhist will fry in Hell for eternity.

Re:And they call me crazy?

[Mr_Huber]

This idea would ultimately be a limit to God. What would happen when, after confronting something mysterious for years, Science suddenly renders up a rather mundane, but accurate solution to the mystery? If a proof of God depended on this mystery, what becomes of it?

Consider this instance. We have two deep mysteries, the smoothness of the background radiation and the seeming presence of dark energy. Both, you argue, don't quite make sense under our current understanding and are, therefore, candidates as proof of a higher power.

Now along come these chaps from Fermilab and demonstrate, using some really neat math, that dark energy is just inflation, the solution to the smoothness problem, writ large. Nothing here that isn't predicted by old theory. We just weren't thinking about it clever enough. Suppose this is all born out. Where does this leave your God?

This is the problem with the God of Gaps. If you go looking at each gap in our scientific understanding and cry, "Here be God!" you are likely to get a nasty shock if the gap is filled.

This has already happened with Creationists who accept some evolution. First, God dwelt in the gaps between species. Microevolution is possible, but speciation requires God. Then speciation is demonstrated in bacteria. Okay, well God is required for multicellular speciation. Then its demonstrated in fruit flies. Okay, well God is required for higher life forms. Then genus level evolution is demonstrated. Okay, nothing can change phylum without God. And so it goes. God is narrowed and narrowed by each burst of science, becoming a pitiful God of Gaps, living in the few spaces left between the known science.

Better, I think, is a reexamination of one's needs and demand for Proof. Or, more precisely, a need for the Proof to fit one's preconceived notions of the nature and identity of God.

Re:And they call me crazy?

[Alsee]

What about all those cosmic rays that impossibly are higher than the Greisen-Zatsepin-Kuzmin limit? It just doesn't make sense, there has to be something creating that sort of order and miracles from chaos.

You're suggesting God created this increadible machine we know as the universe, with stars and planets and light and complex chemistry and superconductors and quantum field effect transistors and life and us... and God in his Ineffable wisdom sticks his hand in and throw around Super-Duper cosmic rays? That he creates this increadible machine where EVERYTHING ELSE works just like He designed it to, according to the laws and mechanisms He established, and then there's this one little bizzare thing that He decides to stand around constantly creating? He had his Six Days of Creation, he Rested on the Seventh Day, and then he decided to come back and spend the rest of eternity just Creating Super-Duper Cosmic Rays that wouldn't otherwise exist? That the natural cosmic rays weren't good enough for him? This single thing to muck up an otherwise perfect creation?

Urk?

prove the existence of God from nature? Maybe something in nature that doesn't appear possible or make sense in nature, yet exists anyway?

God of the Gaps.

If someone wants a God of the Gaps, a God who created a Flawed Universe with Gaps, a God who lives and hides inside these Gaps and Flaws, a God you suggest may be prooven by these unexplained cosmic rays... well they're welcome to him.

If you look for God *hiding* in the Gaps then eventually science will evict him from that gap. It has happened a hundred times before. These cosmic rays will be explained in a year or in ten years or in a hundred years. *That* God will have been slain by science. Slain again and again in gap after gap, even as he is continually reborn in new gaps. That is is a very poor God of an ever diminishing realm, a God locked in a constant war with science. I do not have much respect for the notion of a constantly shriveling God of the Gaps proping up a broken universe.

Do not seek a God of the Gaps. Do not look for God in the gaps.

A God who either set a Perfect Universe in motion (and all of the laws and mechanisms of science/nature) and need not interfere with it, or who created the Universe (and all of the laws and mechanisms of science/nature) and does intervene to preform miracles, that is a God. A God that that cannot be diminished or threatened by science.

This next part isn't neccesarily targeted at you, it is targted at those who follow a God of the Gaps and find themselves led into a battle against science...

Religion should celebrate science, the exploration and understanding of the universe He Created. Science is hardly perfect. Science is a constant struggle for a better and more accurate understanding of the universe. Sceence makes occational missteps, but anyone who believes in a God who would plant false evidence and deliberately lead science astray... they cannot believe anything. If there is a malicious deciving God then we can beleive nothing, nothing we see, nothing we feel, nothing we think we know. Absolute nihlism. If we reject a deceiving God, if we reject nihlism, then we can only believe in a God that supports science. A science that is the best known understanding and explanation of the universe. A God that has nothing to fear from scientific exploration of the universe. Do not seek a Lord of the Gaps, do not follow a god that has anything to fear from science.

-

Re:And they call me crazy?

[jptxs]

While I don't remotely agree with you, I think it's horrid that you've been modded a troll. An act of blatant prejudice (of the intellectual flavor) that only proves your point about many who claim science as rational *and* moral high ground.

The irony is that science involves just as much faith as any religion (from a philosopher's point of view [i.e. my own], science and religion are hardly different systems at all). As you point out (awkwardly), the theories require a belief structure that eventually boils down to an epistomological faith in observation and testing. Too many ignorantly claim science is somehow deviod of or superior to faith systems like religions, when in truth it's just another example of one.

Re:And they call me crazy?

[Anonymous Coward]

That argument may be convincing, to a solipsist, in some abstract sense, but most people, including philosophers, will agree that observation is an epistemologically sound method at arriving at beliefs.

Re:And they call me crazy?

[Anonymous Coward]

So? If you could explain the parting of the sea as the result of some rare lunar event, would that not make it a miracle?

Re:And they call me crazy?

[Anonymous Coward]

Well, God created the universe and all its laws of Physics, etc. However, Sodom and Gomorrah were razed, the sea was parted, etc. Not all of that 'fits' into natural causes. So to your first point, maybe the Cosmic rays aren't going to be explained by a science theory, in which case it's angel's trails or something. And if a valid theory does emerge, then the angel trail theory is disproven. See? I just made a theory, and if its disproven, then we'll be a little bit wiser.

Re:And they call me crazy?

[RvLeshrac]

The razing of cities isn't exactly an inexplicable phenomenon, and neither is the "parting of the red sea," if you accept the "Reed Sea" explanation.

There's little point in producing theories that are impossible to prove. They contribute nothing to a scientific discussion. Nothing wrong with being religious, but if you aren't going to pose valid questions that further the discussion, sod off.

Re:And they call me crazy?

[Phronesis]

What would it take to prove the existence of God from nature?

You're asking the wrong question. What would be needed would be to put the existence of God into a falsifiable hypothesis. Once you know how to disprove the existence of God, you can keep performing experiments to disprove God's existence. If even one of these experiments succeeded in disproving God, we'd definitely know He didn't exist.

On the other hand, the more experiments failed to disprove God's existence, the more faith we could have that his existence had been confirmed by scientific tests.

The biggest problem with addressing God's existence through science is coming up with a type of experimental test that believers could accept as disproving His existence.

Here's an analogy: you can't prove that the speed of light in vacuum is equal to all inertial observers. Any finite number of measurements of c does not prove that it's always the same for all observers. However, it would only take one reproducible experiment in which c is different for one inertial observer to disprove relativity.

The reason we believe the "laws" of physics is because they've withstood so many experimental tests that were capable of falsifying incorrect laws. Proving the existence of God would be similar: He'd have to survive a large number of experiments that were capable of disproving his existence.

Re:Please elaborate

[Anonymous Coward]

No really, what do you mean? Or are you just trying to bash religion?

Hypocrite?

[Anonymous Coward]

I expect your response to be the same for posts bashing religion (Specifically Christianity on /.)

Re:Hypocrite?

[wanerious]

I can't tell if you're merely sarcastic, but yes, being an astrophysicist as well as a Christian, I am equally annoyed by those all too dismissive of theological arguments that they are unacquainted with.

Re:Hypocrite?

[jdclucidly]

Your lose a great deal of credibity, in my estimation, when your proclaimed profession and religion are fundamentally in conflict.

Re:Hypocrite?

[wanerious]

Of course my answer is, then, that there is no fundamental conflict. Hopefully that can restore some credibility. Any conflict between the two can be ascribed to an imperfect understanding of either (or both).

Re:Hypocrite?

[jdclucidly]

How can a claim to be a scientist and not subscribe to natural philosophy, the basis of all science? I don't mean this question in a patronizing way for I truely find it difficult to understand your position.

Re:Hypocrite?

[wanerious]

I admit to not understanding your difficulty. Why would I not subscribe to natural philosophy? I freely embrace science as our best method to understand natural phenomena. Where's the problem?

Re:Hypocrite?

[jdclucidly]

If you use natural philosophy for all matters in the natural world, what then does that leave for Chistianity to say? It is popular among Christians to assume that humans are more than merely natural beings having something spirital as well. Then do you deny that you are a member of the natural world? Would your use of natural philosophy in science stop at scientific matters influenced by humans? And what fields of science are not thusly influnced by humans? If not, then what use is Christianity if it has nothing to say about our world? Why not some more abstract religion which has less dogmatic law?

Re:Hypocrite?

[wanerious]

Christianity deals with, as you suggest, that which is not purely natural (in the scientific sense) --- the right and proper behavior of that supernatural aspect of a person we might call the "soul". Certainly I may suggest that there is some supernatural component to a human person without denying that the person is also a member of the natural world; indeed, I believe that the human form evolved according to our current theories. I don't understand why I must draw a distinction between those phenomena "influenced by humans" and those that aren't.

My Christianity is not terribly dogmatic, I don't think. What dogma bothers you? I like Christianity in that I feel it is a more precise and correct theological formulation than other religions, sort of similarly to how GR is a more precise and correct model of gravitational behavior. I could be wrong, though I must follow my conscience.

Re:Hypocrite?

[Anonymous Coward]

Here's my take on how physics and christiantiy agree (spoken as a physics major and a christian)

"In the beginning was the word, and the word was God."

Since the 'word of God' is Law, what's to say that there cannot exist spiritual law, in addition to natural law, and that on some level (ie: being The Word) the two are not one and the same...

Since we have nowhere near a full understanding of either religion (ie the Mind of God, not some church's doctring) OR science I think this is a posibility

To be more specific - in the Old Test. - God is often described as the "I AM" - rather than personified as a human-like, but big and powerful, he IS, and is left at that. In other words, God is beyond our understanding and conception. Combine that with the beginning of John - that God is his word, God's word is his Law, God is The Law. The sum total of all law - natural, mathematical, physical, spiritual, etc. We can catch glimpses of God in natural law as well as spiritual law, but just as we 'see dimly' as it's put in Romans I think - in science, every discovery will prompt more questions.

One more ingrediant - initial conditions. If God is the sum total of all law - and was from the beginning - He could BE AROUND TO HAVE ALL THE INITIAL CONDITIONS. So he gets to be omnicient - and the universe for him is deterministic, he is by definition omnipotent - because everything that does happen is a result of his law.

Of course, NOT having the initial conditions of the universe - we are bound by observation. And because of Hisenburg Uncertanty - observation for us leads to a NON DETERMINSTIC (although there are highyly favored probabilities) universe.

So not only do I think there is room for Physics and Christianity to agree - but maybe because of the GOD->Deterministic, US->not ... quantum leaves room for miracles :) ????

Re:Hypocrite?

[jdclucidly]

Christianity deals with, as you suggest, that which is not purely natural (in the scientific sense) -- the right and proper behavior of that supernatural aspect of a person we might call the "soul". Certainly I may suggest that there is some supernatural component to a human person without denying that the person is also a member of the natural world; indeed, I believe that the human form evolved according to our current theories. I don't understand why I must draw a distinction between those phenomena "influenced by humans" and those that aren't.

You may suggest that a person is both natural and supernatural but I would not be incorrect, either, to suggest that that is a paradox. If we were to believe this assertion, as scientists, then indeed any science where the human is the subject of research would be permanently fallible, would it not? And indeed, if we say that supernatural phenomenon can be exposed in one natural body -- namely humans -- who's to say that other natural objects would not expose providence at the whim of God or other supernatural intelligence? What use is science in this world ruled by the supernatural's will?

My Christianity is not terribly dogmatic, I don't think. What dogma bothers you? I like Christianity in that I feel it is a more precise and correct theological formulation than other religions, sort of similarly to how GR is a more precise and correct model of gravitational behavior. I could be wrong, though I must follow my conscience.

I only brought it up to give visibility to the claim that Christianity's text (the Bible) makes many claims about the natural world including assertions about the history of the world which clearly contradict the findings of science. The question I have here is if you can pick and choose the parts of the Bible that you want to believe, are you even a Christian, more accurately a Unitarian or something else entirely?

Re:Hypocrite?

[wanerious]

Well, I would say that there are avenues of inquiry regarding humans that tend to lie in the domain of the purely physical, as opposed to those that test our "spiritual", or conscious, selves. The evidence is that the behavior of other natural objects, especially in simple systems, behaves closely according to a set of physical laws. I suppose there is still room for the supernatural in this, but there's no evidence of it yet. To the extent that there is a pervading supernatural will, its effect is thankfully in tune with physical principles.

Interestingly, I was raised Unitarian, though now I'm a member of a Methodist church and was fairly recently baptized. True, the literal readings of biblical history contradict my own professional field, but I must assume that these contradictions arise from an imperfect understanding of the text. They are brought in harmony in the realization that the Genesis stories are truly mythic in nature, communicating truths of the right relationship between God, man, and His creation. It is not necessary for me that they are literal history. It is not that I'm picking which parts I want to believe, but that I must struggle to interpret correctly those parts that are in conflict. A passage may contain spiritual or theological truth, as the parables do, and yet no historical truth. The pleasure is in the struggle for interpretation.

Re:Hypocrite?

[jdclucidly]

Well, at the very least I now understand your assertions and perspective. It seems that there are two points upon which we disagree where no progress will be made through argumentation:

• If there were some supernatural phenomenon that we could observe -- for which there were evidence as you say, would it be supernatural? I hold that it would not.
• Since you don't hold to many Christian assertions about the natural world, since there can only be one definition of what a Christian is in our language and since this seems to contradict the commonly agreed upon definition, I don't consider you a Christian at all. Perhaps a Unitarian with affinity for Chrisitan ideas. In any event, I think of you now as a scientist by day and a spiritualist with interest in Christianity by night. Needless to say, I find these incomensurable.

Re:Hypocrite?

[wanerious]

I think I agree with your first point. Science can, bascially by definition, only concern itself with those things that are non-supernatural. Perhaps there could be evidence for the supernatural, but only to the extent that the phenomenon cannot be explained by natural means. One ought to still hold to the possibility that future scientific discoveries might be able to explain the presently mysterious.

Yes, we obviously disagree as to what a Christian is. I am a follower of Christ's teachings, as I understand them, and believe him to be a human manifestation of God incarnate. I also believe in the Apostle's Creed, which by many accounts is a sufficiently small set of axioms to "test" for Christianity. Perhaps I don't pass fundamentalist muster, but I'm comfortable with that. In any case, thanks for the conversation.

In the beginning

[MacII]

do I need to say more?

In the words of Rainer Wolfcastle...

[isny]

Einsteiiiinnnnnnnn!!!!!!! (shakes fists in the air)

Would this mean the universe is closed?

[JoeGee]

Or do physicists still think everything is doomed to continue flying apart until the heat death of the universe in the distant future? Is the Big Crunch back in the picture?

-Joe G.

Re:Would this mean the universe is closed?

[Anonymous Coward]

No, eternal expansion is still the best conclusion from an accelerating unvierse, even though their proposed mechanism for the accelerating expansion has changed.

Re:Would this mean the universe is closed?

[MightyMartian]

Current models indicate that there is simply not enough matter to halt the expansion. It appears the Universe is headed for a heat death.

Re:Would this mean the universe is closed?

[Curunir_wolf]

My impression is that these guys are trying to preserve an old theory (inflation) that was recently discredited by adding a new, kludgy "unseen ripple" idea to the theory.

The latest perterbations of M-Theory have some elegant and intriguing explanations for the origins of the big bang, the behaviour of gravity, and don't really rely on dark energy (well, there are workable theories that explain the effect).

How much money do they want to "test" this crazy idea, anyway? Is this really a productive way to spend our research tax dollars?

Re:Would this mean the universe is closed?

[Anonymous Coward]

My impression is that these guys are trying to preserve an old theory (inflation) that was recently discredited by adding a new, kludgy "unseen ripple" idea to the theory.

You're wrong. Inflation has not been discredited; in fact, it now has good experimental support (WMAP observed the acoustic peaks in the angular power spectrum of the CMBR). These guys are trying to do the opposite: explain the observations without introducing a new idea (some kind of new "dark energy field"); rather, they are arguing for a previously unnoticed implication for the existing, standard inflation theory.

The latest perterbations of M-Theory have some elegant and intriguing explanations for the origins of the big bang

M-theory? Don't make me laugh. M-theory can produce about a billion different scenarios for the Big Bang, including most of the inflationary scenarios that you were just deriding. (Most M-theory models of cosmology include inflation, you know.) We have no way of narrowing things down to get M-theory to predict which one of these speculative scenarios may apply to our universe, we have no evidence for all of the new physics that M-theory requires (strings, extra dimensions, supersymmetry, etc.)

If the CMBR spectrum and dark energy can be simultaneously described by introducing one simple new field (the inflaton), parsimony gives that the win over M-theory. And when you get down to it, inflation is not inelegant either. Now, if there is some actual experimental evidence for M-theory, which doesn't also support existing theories, we might have a reason to take M-theory cosmology seriously.

How much money do they want to "test" this crazy idea, anyway? Is this really a productive way to spend our research tax dollars?

The tests of this theory would be done anyway, because they test all the competing theories at the same time.

Re:Would this mean the universe is closed?

[Curunir_wolf]

You're wrong.

No I'm not. Inflation predicted that the expansion would be slowing by now, not accelerating. Calling the discovery of the acoustic peaks in the CMBR "good experimental support" for inflation is quite a stretch.

M-theory? Don't make me laugh. M-theory can produce about a billion different scenarios for the Big Bang...

Not ones that produce mathematically sound models.

If the CMBR spectrum and dark energy can be simultaneously described by introducing one simple new field (the inflaton), parsimony gives that the win over M-theory.

I call bullshit. Inflation IS inelegant. It doesn't provide any clue to the cause of the big bang, and the conditions that could cause inflation aren't explained.

I don't know why you would support such an untenable position and completely dismiss a theory that can produce such elegant models like described here.

Re:Would this mean the universe is closed?

[Anonymous Coward]

Inflation predicted that the expansion would be slowing by now, not accelerating.

Inflation is largely a theory of the early universe. It is not generally considered to have anything to say, one way or the other, about the later expansion (accelerating or not). The authors of this paper think that inflation does influence the later stages of the expansion, but even if it didn't, the need for dark energy does not in any way imply that inflation's predictions have failed; a later accelerating expansion is in no way incompatible with early-universe inflation.

Not ones that produce mathematically sound models.

Ha. You name it, M-theory can produce it. It's got braneworld scenarios, pre-Big Bang string cosmology, eternal inflation, and a pile of other models, dimensional decompactification, and a whole pile of other proposals floating around, with no way of telling which is better than any other.

It doesn't provide any clue to the cause of the big bang

It's not supposed to. Inflation is a theory of what happens after the Big Bang. Unless you subscribe to Lidne's eternal inflation, which is a theory of both.

and the conditions that could cause inflation aren't explained

Wow, what a hypocrite. You claim that the conditions that could cause inflation aren't explained, and then turn around and promote the ekpyrotic scenario. I hate to break it to you, but that scenario doesn't explain the conditions that could cause a Big Bang. It just ASSUMES the existence of branes of the right dimensionality, hitting each other in the right way, with the right gauge fields coupled to them, in a cold, flat, and empty space, in a state close to a BPS state, and so on and so forth. This is no more elegant than postulating an inflaton potential (and is in fact more ad hoc, as there are at least various plausible candidates for an inflation that make specific predictions for its potential). Inflation is in fact very elegant, because inflation can occur in a way that's largely independent of the initial state, rather than having to make all kinds of ad-hoc assumptions. The only "freeness" in the theory is the functional form of the potential, and there are plenty of theories that make
concrete predictions for that.
And, once again, I remind you that even many (and I would say most) string theorists support inflation. It's just extremely easy to have an extra scalar lying around in your theory -- be it a conservative exension to the Standard Model, a GUT, string/M-theory, or whatnot -- that acts as an inflaton. In fact, it can be hard to produce interesting new theories that don't have inflaton fields running around. The moduli fields in string theory are a good example. Even among string theorists, the more exotic proposals like ekpyrotic, PBB, etc. are regarded as extremely speculative, not as something that holds any real answers as yet.

Why is it okay..

[mpn14tech]

for Fermilab to announce some scientific result by press release, but if some other institution does it they get slammed for it.

Shouldn't they at least wait until the paper is peer reviewed and accepted before doing a public announcement like this?

Re:Fermilab employee chiming in

[Scott7477]

It seems to me that the rationale for constructing ever larger and more expensive high energy physics labs sooner rather than later(i.e. by diverting defense spending to pure physics) is that we're just around the corner from producing the grand unified theory and since this is the holy grail of science it is the only human activity that really matters. The reality is that simply building bigger colliders isn't going to produce a solution. An analogy that I once read that referred to studying particle physics using colliders goes as follows: it is like trying to figure out how a car works by accelerating two cars into each other and looking at the pieces that are left(we are talking about very small pieces remaining).
We currently have no way of observing the behavior of subatomic particles operating in their natural environment(see Heisenberg's uncertainty principle).
Also, there is a truly enormous amount of data which has been generated by older and existing colliders which has yet to be fully analyzed. It might be reasonable to not operate the existing colliders for, say, a year, and devote those dollars to paying physicists to crunch the already existing data.
Given the above, I don't see maintaining high energy physics budgets for the next few years at existing levels or even with some cuts as a serious detriment to the progress of the US or the world. I'm sure that some physicists would be upset as this tips over the applecart of their plans for fame as the next Bohr or Einstein.

Re:Physics data and theories - how suspect are the

[MightyMartian]

Well, the universe seems rather uniform irregardless of the direction we look. If there were something messing with observations, then I imagine it would have to be damn close to us, if not right on top of us. The mapping of the CMBR rather indicates that these are reliable observations.

Hear Hear

[theolein]

Very well put! What really shocks me is that the cowboy mentality is even so prevalent here on slashdot, where many people interested in technology seem to believe that science is of no worth, but God and bombs are.

I find it simply frightening, because I think it poses a very significant threat to the future of the USA, which is heading down the road of becoming a military power without the brains needed to steer it in a wise direction.

Re:Physics data and theories - how suspect are the

[Artifakt]

You have a valid underlieng point. A lot of this research involves data that passes through many man-made intermediaries before it becomes something a human mind can work with, and is about conditions where normal common sense and intuition are not at all reliable guides.
On the other hand, some of your rhetoric is an answer of sorts to your own questions.
It's not usually stated as an explicit rule of science, but for a working scientist, phrases like "in a way we cannot detect" are themselves something that requires exceptionally strong proof. By default she would mostly first try to test for "in a way that we have not yet detected". Even if she had a few failures working along that line, she would probably try to find other new methods of possibly detecting something, or move on to some other problem.
If a problem seems stagnant for a very long time, usually a whole generation of researchers or more, someone may try to prove there's a fundamental reason we just can't do something, but even then, it's usually part of developing a theory that has some more positive aspects.
In the same way, she might first look for explanations that might require minor reframing of a single small section of theory, and not major rewrites of multiple whole sections. Most Cosmologists are very wary of claiming they have done something huge until the first Nobel or getting Einstein's old office.
You might Google for (Sir) Karl Popper. He wrote a lot (and well) on what things like 'testability' or 'proof' mean to a scientist. I'm just trying to adapt some of his arguements to the way you phrased your questions. You might also Google for Thomas Khun, but I recommend reading a bit of Popper first. A lot of Khun's writings have been thrown around too freely of late.

Re:Nothing for you to see here, if you have an MBA

[Anonymous Coward]

And they say science jokes aren't funny!

Re:Please elaborate

[Anonymous Coward]

He doesn't need to. Religioun manages to bash itself quite well before anyone who actually does a little thinking of his own.

Theories

[Elrond]

Since everyone seems to have there own theory about this... here is mine.

Our universe is just a bubble in a glass of soft drink and when we reach the top everything well be made clear(or bigger or something.. err)

Re:Nothing for you to see here, if you have an MBA

[__aaclcg7560]

I was all set to register for cosmetology school, thinking it would be a growing field with lots of opportunities.

There's still a need for hair stylists and designers if you decide to go to cosmetology school. However, the only dark matter you're be dealing with is what clogs the drains. ;)

It's not dark matter...

[Biomechanical]

It's fire.

In the beginning was nothing right? Then a Bang.

I'm thinking about this Bang. Nothing, not absence of something nothing, but Nothing. Nothing exploding.

Fire. An explosion is fire, burning combustible materials and releasing hot gases that expand.

In the middle of Nothing, there was an Explosion.

Is it possible that our universe is bounded, instead of Nothing, by Anti-Energy? The quantum equivalent of reverse-charged light?

Could a single, "mutated" quark, quasar, or thing, become charged the wrong way from subtle interaction with it's surrounding particles?

Matter and Anti-Matter. Touch one to another, and stand well back.

The universe is expanding, and it encompasses all space and time as we know it.

Could it be like a big sheet of paper (paper == anti-energy) and someone (rogue element) "ignites", switches polarity, triggers a "burn"?

When you light the centre of a sheet of paper, it expands, sometimes uniformly.

Are the boundaries of our universe a massive bluish-white of fire? Masses of matter reacting against the inverse Nothing of anti-matter, burning, accelerating like a brush-fire on a hot day.

If the universe is all time and space then it doesn't necessarily have to be planets and stars out there on the boundaries.

It could be the Burn, already moving faster then light from the instant it started, expanding constantly, releasing energy that is recycled back into matter in our own space-time.

Re:It's not dark matter...

[MoralHazard]

What. The. Fuck?

How did this get modded "Interesting"? Oh, wait... there's not "Incoherent" option.

The force

[Muhammar]

It has the dark side and it has the light side. It holds the universe together...
"I am your duct-tape, Luke."

Interdimensional pressure

[Anonymous Coward]

Somewhat along the lines of a previous reply about gravity bleeding into other dimensions, If you had a stack of papers, each with random ink splotches of varying sizes and then you placed them all against a bright light source, with enough papers in the stack it would appear to be a pretty uniform makeup from the splotches.

If reality is nothing but a dense layer of universes, each with their own random ink splotches (ie gravity from planets, stars, galaxies, etc) and they do bleed over, that could explain the relative uniformness of our own observable universe. Just a thought.

No Direction Goes Beyond the Boundary

[BrianMarshall]

Let's say we've reached the edge of the universe, what happens when we step beyond that boundary?

I am not an expert, here, but I believe that there are no directions you can move in space that cross the boundary.

In the balloon analogy, the 2D space is expanding, but there is no direction, in that 2D space, that moves off the balloon.

Interestingly, everywhere on the balloon is just next to outside the balloon. If this is true in our 3D space, everywhere is just as close as everywhere else to the edge of the universe.

Actually, come to think about it, this makes sense - if there is no epicenter of expansion, there is no where that is farthest out.

Not Needed

[hisstory student]

Whew! It's a good thing we've got lots of folks here at Slashdot that have the answers to all this incredibly complex stuff. Uhhuh. Right. :-b

Only on Slashdot

[3.5 stripes]

Does a camel pilot get shot down by a mustardman.

Sounds like a They Might Be Giants song.

13 Questions... Answered

[cyb3rllama]

It turns out that I was right about numbers 9 and 12.

Re:Dark Energy

[JerriMan]

Dark Energy is not the same as the cosmological constant. There are other theories like k-essence and quintessence which also are used to describe dark energy. The difference between this theories is, that the cosmological contant is, well, a constant, whereas the two other types of theories are dynamic.

Tough luck

[Fussen]

Now all those scientists that believed in dark matter will have to be fired or start working on the more traditional and understandable light matter.

"Yes I did think dark matter was involved.. would you like fries with that?"

Re:Physics data and theories - how suspect are the

[Anonymous Coward]

Not so suspect as to prompt calls for "physics is just a theory" disclaimers on textbooks.

HHGG is right!

[toomanyhandles]

It really is just eddies in the space-time continuum....

right ...

[cascadingstylesheet]

Well, thank goodness science is so sure about cosmology. I was beginning to feel a bit ashamed of all the creationist-bashing I was doing. So it's epicyc ... I mean, "inflation". Got it.

Huh..

[Xaggroth]

so THATS what it is like living in a plane of existance governed by mr. stretch.. ..I'm sure all the religious folk are feeling kinda bumed that the higher power isn't something cooler..

"curved space" is alternative explanation

[peter303]

Astrophysicist Allen Lasenby gave the keynote lecture at SIGGRAPH last year suggesting dark energy was really intrinsic elliptical curvature in space. (He gave the keynote talk because he is an expert in computational geometry used both in graphics and physics.) Other physicists agree that space may be curved, but claim that the curvature is caused by dark matter or dark energy in the cosmos.

Location, location, location!

[stuffduff]

And if the universe is really steady state after all, then the big bang and the spacetime distortions which it caused are really just a local event. Our horizon is limited by the amount of expansion the shock of our big bang caused, like the reflections on the back side of a ripple headed away from us...

Across the Universe - The Beatles

OT

[Darby]

Disgruntled Defence Signals Directorate employee, am no longer allowed to exchange secrets for diet coke.

You used to didn't you?

What happened, Dude?

Did you get caught exchanging secrets? Is your garage filled up with diet coke and your wife won't let you get any more until you drink it?

What's the deal?

More info?

[Anonymous Coward]

Intrinsic is just another way of saying unexplainable: saying the redshift is "intrinsic" means that it is not due to anything. In other words, it has no explanation. That doesn't exactly seem scientific.

The red shift is observed. If it's not due to Doppler, there has to be an alternate mechanism proposed. Intrinsic is not a mechanism, just a description.

Can you clue me into any work on what this "intrinsic" mechanism would be?

Re:More info?

[nimblebrain]

Intrinsic is just another way of saying unexplainable: saying the redshift is "intrinsic" means that it is not due to anything. In other words, it has no explanation. That doesn't exactly seem scientific.

On the contrary. You do not have to have an explanation in hand. Dark energy, for example, has a name, but not an explanation (calling it Einstein's cosmological constant doesn't help much either :) Yet it can be used to generate hypotheses and tested, given certain assumptions.

In this case, we have an existing theory, and some disparate observations (e.g. at their measured redshift distances, older galaxies in any cluster seem to group on the near side, which is anti-Copernican) that have raised suspicions.

Having a hypothesis that expansion of space cannot statistically account for the observed redshift is a perfectly valid, and scientific, premise for experimentation.

That said, there are some theorists working on the problem.

Contenders for a mechanism:

• CREIL
• Compton Effect
• Plasma Redshift
• Variable Mass Theory (cf. Mach's Principle)

Some of these have got to be wrong, of course, (and this doesn't rule out other mechanisms) but those will show up on further experiments.

Cheers :)

Re:More info?

[Anonymous Coward]

The Compton effect is definitely not responsible for cosmological redshift. Most tired-light models fail at least one of the tests in the preceding link. And links to a bunch of unpublished and uncited preprints on the arXiv are not terribly credible.

Correction to the article

[jgoemat]

His "cosmological constant" represented a mass density of empty space that drove the universe to expand at an ever-increasing rate.

When Einstein put the "cosmological constant" into his formulas, they hadn't found out yet that the universe was expanding. The constant was there to make the equations work for a static universe.

Re:The true explanations for the Universal Expansi

[Alsee]

a red rubber ball that belongs to gigantic beings,
I simply fear they will begin playing dodgeball soon.

They may have other plans.

-

Fathoming the unfathomable

[ltmdweaver]

I kind of look at this kind of research in the same vein as the old questions...

When did you stop beating your wife?

Interesting, but not particularly useful. Of course if somehow they can use this knowledge to age Scotch Whiskey a little faster, maybe I can get a little more juiced.

mdw ;-)