Slashdot Mirror
Chandra Provides Support For Dark Energy
starannihilator writes "The Chandra X-Ray Observatory has provided new evidence supporting the existence of dark energy, the force causing the acceleration of universal expansion. The new findings support the theory that the universe will expand forever, provided there is enough dark matter. CNN and Newsday are running the story, originally reported by NASA. Chandra's site has some good images and information on the three galaxies clusters studied (Abell 2029, MS2137.3-2353, and MS1137.5+6625)."
I am eagerly awaiting the next annoncement where someone again finds evidence to refute the dark matter claims. It seems like the science; "Dark Matter is like this" - "No, it can't be, actually it's like that". Is not going to end soon.
Join me. Come to the dark side, and together, we will expand the universe.
Kinetic stupidity has a new brand leader: Allen Zadr.
I dated a girl named Chanda once. Dark energy is a good way to describe her.
Are those last two patented by Microsoft?
Maybe someone can explain... But when the CNN article states that the universe is "accelerating", does that mean it's really accelerating? I thought it was decided that the universe's expansion was expanding at the speed of light. So, I would assume that by accelerating they mean growing bigger and not actually accelerating faster than the speed of light. Unless, this Dark Matter is something that can bend the known laws of physics and travel faster than the speed of light?
Hmmm.
Considering they are pics of things between 1 billion and 6 billion light years away.
If only the goatse guy was that far from the camera in that photo.....
Boffoonery - downloadable Comedy Benefit for Bletchley Park
Does this mean that there's a little creature with a voracious appetite pooping in space?
how do we know if something outside the universe isnt affecting it.
I'd like to think we live on an electron in orbit around the proton of a molecule as part of a giant coffee mug -- our universe is expanding due to some even bigger geek having just poured hot coffee in our universal mug.
It's "dark" cuz that's how this geek likes his coffee.
If the universe was expanding at the speed of light. It would look pretty dark out there at night.
Or at the very least it would be awfully hard to see some of those distant galaxies.
Nibbler
with the existence of dark energy, we can now work at taping the dark energy or the Zero Point Force to get infinite energy!!!
I am the Alpha and the Omega-3
Gravitation is a shadowing effect. (Yes, all the formulae still work, except when you get out towards the edges of space)
--Mike--
Because I've got a kickass deck of Pokemon cards that's centered around Dark Energy. . . that's right, I'm baaaad.
These are my friends, See how they glisten. See this one shine, how he smiles in the light.
12 Dark Crystals, 3000 Gil. Send /tell to Aribaud /obscure reference?
Sigs? We don't need no stinking sigs!
This telescope is doing the exact same type of science that hubble is. The only difference is there is not some irration emotional attachment to this telescope and there is a much better return on investment for dollars going forward.
No. The expansion of the universe refers to the fact that distant galaxies are moving away from us, and that the farther they are, the faster they are moving. This is expressed by the Hubble constant, which has a value of about 50 km/s/Mpc.
The acceleration of the expansion is reflected as this "constant" increasing with increasing distance.
The acceleration is caused by Dark Energy, not Dark Matter.
Dark Matter is either normal matter or subnuclear matter that makes its presence felt as increased gravity, but is not directly observable.
Dark Energy is not well understood at all.
HCG 50a = 2MASX J11170638+5455016
11h17m06.4s +54d55m02s
Does anyone else think that the cutting edge of physics is starting to resemble Ptolemy's system of astronomy? With all this 'dark' energy, and 'dark' matter, it's beginning to look like a lot of hand-waving.
Increasingly complex adjustments (e.g. epicycles) were made to Ptolemy's system to explain the observed motions of the heavenly bodies. Then along comes Copernicus and tells us that we've been looking at it inside out all along, things are simple after all, we just have to adjust our viewpoint.
I think physics is overdue another Copernicus.
... that all Dark Matter comes from the feces of the Nibblonians. Each pound of which weights over ten thousand pounds. Therefore, if there is this much Dark Matter, Dark Energy must exist to cause the expansion of the universe.
Dark matter isn't anything new, I'm pretty sure I've had that magic card since like... Third edition or something. hehehe
--untwisted
The headline to this story is an exaggeration. Of course, you can't blame it on the author seeing as the headlines of the major news sources were exaggerations as well.
So what, we have more evidence the universe is expanding at an accelerating rate. WE ALREADY KNEW THAT! This is just another indication that it's happening. This doesn't "prove" the existence of dark energy. It's still entirely possible (and I would suggest probable) that we just don't know the entire story about gravity. Physicists have gotten gravity wrong before after all.
i always hear about the expanding, but what exactly are we expanding into?
In fact my general theory states that any container will keep expanding as long as you keep stuffing enougth material into it.
Can I have my Nobel prize now please?
And if you thought that was boring you obviously havn't read my Journal ;-)
The original poster has it wrong, more dark matter decreases the expansion of the universe as one would expect, dark energy does the opposite changing the state function of the universe and thus allowing it to expand. IAA astro-physicist
What, no pictures of "dark matter"?! That I'd call an announcement!!
Chandra is the word in many Indian languages for the Moon.
Whenever life get's you down, Mrs. Brown
and things seem hard and tough,
and people are stupid, obnoxious or daft,
and it feels that you've had quite enough---
Just remember that your standing on a planet that's evolving,
revolving at 900 miles per hour.
It's orbiting at 19 miles per second, so it's reckoned,
a sun that is the source of all our power.
The sun, and you and me and all the stars that we can see
are moving at a million miles a day,
in an outer spiral arm at 40,000 miles an hour,
in this galaxy we call the milky way.
The galaxy itself contains 100 million stars,
it's 40 thousand light years side-to-side.
It bulges in the middle 30 thousand light years thick,
but out by us it's just 3000 light years wide.
We're 30 thousand light years from galactic central point,
we go round every two hundred million years
And our galaxy is only one of millions and billions
in this amazing and expanding universe.
Musical interlude
The Universe itself keeps on expanding and expanding
in all of the directions it can whizz.
As fast as it can go, the speed of light, you know
A million miles a minute and that's the fastest speed there is.
So remember when your feeling very small and in-secure,
how amazingly unlikely is your birth.
And prey that there's intelligent life, somewhere out in space,
'cause there's bugger-all down here on Earth.
Attribution for the above lyrics to Eric Idle.
Kinetic stupidity has a new brand leader: Allen Zadr.
Recall that Hubble's law is v=H*D where v is the velocity a given galaxy is moving away from us and D is its distance from us (and H is Hubble's constant). So closer galaxies are moving more SLOWLY away from us than distant galaxies. And hence, closer galaxies may be moving away slower than c while more distant galaxies may be moving away faster than c.
I have a particle around here somewhere that I measured to find its precise speed was very slightly faster than c.... I would show it to you as proof but I cant seem to find it anywhere! ;o)
This proves nothing and provides no evidence. Read the report... everything it states about ratios and measurements involves assumptions. This isn't science. This is a bunch of people with too much time on their hands and not enough real information.
This isn't science.
unknown type of material, is POSTULATED to hold clusters together.
The observed values of the gas fraction depend on the ASSUMED distance to the cluster.
they are THOUGHT to represent a fair sample of the
ASSUMING that dark energy is responsible for the acceleration
The new Chandra results SUGGEST that the dark energy
That was proved to me years ago when I met my housemates girlfriend. She was positively festering with it. She radiated me with it so much of it that I now have a latent ability to detect dark energy within a 5m radius.
I've seen a few references to a theory of a final "big rip," in which everything (even atoms) are torn apart by the expansionistic force.
Would this apply to black holes, as well? If black holes aren't ripped apart, would they continue to provide areas of gravity strong enough that particles in the vicinity don't undergo the rip?
--When you buy proprietary software, you don't get better software. What you get is the right to complain about it.
Uh, dark matter and dark energy aren't the same thing.
tasks(723) drafts(105) languages(484) examples(29106)
I should point out here that it's also been theorized that the center is in fact pulling things back in - but this is an old theory, that hasn't gotten much press lately.
The accelleration of the expansion is about the inner layers of the universe accelerating to match (more closely) the speed of the outer edge.
So, it's not really acceleration beyond the speed of light, but an accelleration of the slower contents within the universe.
Think of an empty baloon in a centrafuge. The heat will make the baloon expand, and as the spinning keeps moving, the inside air will press harder against the sides - causing more heat and more expansion. The air that's not at the outside is going to "catch up" to the air at the edges.
Of course, this needs to be adjusted to understand that the "balloon" has no outer bounds, isn't going to pop, and has a near infinate amount of matter inside..
Kinetic stupidity has a new brand leader: Allen Zadr.
From the Micro$oft school of cosmology. Take something ( a cosmological model ) that barely works, find out there's a yet another problem with it, and patch it ( with blather about dark matter ) in the hope that it works. Then find out that by introducing the patch to fix one problem, you find another ( er... what exactly is dark matter? Anyone? Please? )
Hey, I rubbished Micro$oft and the whole of modern cosmology in one post. Cool.
There was some PBS special a little while back that talked about "string theory" of reality and the possibility that the "Big Bang" was actually a big "collision" between this and another dimmension. The "collision" or interaction between the two different dimmensions not only created tremendous energy but also left some material from the other dimmesion in this one, dark matter. That is why the stuff is invisible with no known origin but somehow detectable. Kind of like the Old Ones.
The names chosen, Dark Matter and Dark Energy reminds me of the 'ether' that space were filled with. I have a feeling that the current theories will go the way of the ether...
Does everything include nothing?
Later, after astronomers found the universe to be expanding, Einstein called the cosmological constant his greatest blunder. But theorists have been taking a new look at it since 1998, when astronomers found evidence of a repulsive counterpart to gravity in studies of distant exploding stars called supernovae.
Even when he's making stuff up, he's still right... We just don't find out until 80 years later.
This is great news!
>The new findings support the theory that the >universe will expand forever
I was afraid that the universe would stop expanding and start collapsing and that would kill us all!
Why are they ignoring the obvious (at least to me) possiblity that the universe oscillates around some optimal size. Imagine the universe as a rubber ball. Squeeze the ball and let it go. Every particle inside will immediately start moving away from the others at an accelerated pace, continuing to accelerate until passing the rest boundary, when it will start slowing down. What's causing the expansion? How about the reduction of space curvature? Imagine space as a tablecloth (ok, so I'm knee deep in analogies :) on a table with a hole in the middle. Place a heavy pitcher in the middle and the tablecloth will be pulled through the hole, pulling its edges closer together. This is what happens around a star according to general relativity theory. Now, the star is constantly radiating energy and losing mass, so the space is constantly uncurving. Because it is uncurving, it is expanding. When all the stars burn out, space will start collapsing again as energy falls into black holes. Then the black holes coalesce and make the big bang singularity, which explodes for some reason and everything starts all over again.
Ahhh...all the dark matter is probably composed of Matrioshka Brains ;)
Guth might be right, after all. Automata rules!
As others have said, accelerating expansion means that objects very distant are moving away from us faster than closer objects are moving away from us. If you have time for some interesting reading, I'd recommend a title called Atom which is very readable and is a good primer on theory from the big bang to present time. It won't answer many questions about dark energy, but if anything, it'll give you a good idea of what we know in very readable terms and most likely get you to want to read more :) It was my first book on the subject, and it certainly had that effect. Note that I'm no physicist, just a curious reader.
It may be possible to have a universe that is expanding and contracting at different times based on variables we have no ability to measure, hence never be able to know which way we are going to go, only where we seem to have gone.
For some great educational sources for the non-astro-physicist, see The Elegant Universe excellent program (my six and ten year olds understood most of it). A few other articales are at Sky and Telescope and Scientific American
InnerWeb
Freud might say that Intelligent Design is religion's ID.
An interesting read about all of this stuff is "The Inflationary Universe" by Guth. I read it back in an advanced astronomy course in college.
:-)
I imagine a lot of the theories have been proven/disproven by now (published in 1998, I think?), but it was a good read. A little dry in some parts, and somw parts assume that you know a few basics of astronomy/expansion theories, but overall a very good read.
Give it a shot.
here: http://www.davidtownsend.com.au/black.html
you may find the Higgs in this signature.
when you have a really cool joke all worked out, you go to type it into SlashDot, you hit submit, and realize you have a spelling error that completely breaks the joke. Happens to me all the time.
American natve peoples. Not residents of India.
I've always been bothered by the "the universe will expand forever, and it's accelerating" theories.
Not that I have an a fraction the knowledge or mathematical skills of these scientists; but correct me if I'm wrong.
Doesn't gravity effecct objects regardless of the distance between them? Meaning to say, that gravity, however weak, will always have this attractive force.
so, won't this energy causing this accelerating expansion eventually burn up/out?
couldn't the universe be Like the release of a stretched-out, very long rubber band (played back in slow motion). At first release starting from a velocity of 0 and then accelerating. but after expending it's energy, slowing? heck, then even retracting?
in other words, what evidence supports that this thing is going to expand at an accelerating rate forever? seems like gravity is going to get a little upset about that eventually.
A larger pair of jeans.
oh... sorry, I thought you were talking about Americans...
// "Can't clowns and pirates just -try- to get along?"
How can anything possibly go faster than c?
When you lose something irreplaceable, you don't mourn for the thing you lost, you mourn for yourself. - Harpo Marx
not necessarily hard to see ...
if something travels faster than sound away from you but makes loud noise, the noise still reaches you in due time. A shining star moving away from you faster than light will be farther than it appears
BUT if nothing can move faster than light relative to you and me, is it possible that the light from the distant star is just passing through some stuff that makes the light look like it is from a faster-than-light star? Maybe it's all an illusion
Know your pads. One time pad: good for cryptography. Two timing pad: where to take your mistress.
There is no problem with space-time *coordinates* moving with respect to each other faster than c . Consider the old analogy of dots on an expanding balloon. The dots are moving away from each other, yes, but that is a result of the expansion of the *coordinates* of the balloon. The dots are not actually moving about the balloon's surface. When we say that the galaxies are expanding away from each other, it is subtle and important to realize that they are *not* moving through space, but rather that the expansion of space itself is carrying them along.
>everything it states about ratios and measurements involves assumptions. This isn't science.
Yes, it is science. There are observations made that are attempting to confirm or disprove predicitons made consistent with their hypotesis. As for your distaste for the choice of language, particularly the weasle words; that's the way scientists write."Recent observations of a massive shockwave, intense gamma, beta, and alpha radiation, together with so far unrepeated visual observations of what is thought to be a very large smoking crater located at what appears to be the former site of the City of Los Angeles are not inconsistent with the suggestion that a large thermonuclear device or some similarly destructive object may possibly have detonated in Southern California. Our research group is meeting to design further field tests of this hypothesis and it is anticipated that a team of sacrificial graduate students will be sent to the site in the reasonably near future for purposes of further data collection."
Some mornings it's hardly worth chewing through the restraints to get out of bed.
No, honey. Dark matter is slimming.... Honest.
www.facebook.com/DareDefendOurRights
www.fairtax.org
... never was so much inferred from so little.
When the Age of Aquarius first began, the Universe actually started to contract on itself. But then people realized they still didn't like their neighbors. Since then, with increasing rudeness, road rage and the like, everybody hates each other at an accelerating rate, and the universe has stopped contracting and is just starting to grow again. Do you try to be close to people you don't like or do you try to get away from them. Its the same with the whole universe; that's why its flying apart at an accelerating rate.
Now it's the age of Post-Taurus and what the bull left behind.
I was worried about it falling down.
Doesn't it make you feel good to know that our freedoms are protected by politicans, lawyers and journalists.
I thought the photon was its own antiparticle.
Here's a quick summary of the technique:
[TMB]
Here's a link to the article, which is accepted to MNRAS.
[TMB]
I watched this program and I thought it was awful. Beautiful graphics, yes, but almost completely void of any informed content whatsoever. String theory is an almost completely untestable theory. It's elegant, I'll grant you that, and it's completely exciting, in that it explains everything whilst unburdened by anything resembling reality, but it is just a very abstract theory. I remember sitting down to watch this program, and I was tremendously disappointed with it. A real shame.
When I was a young astronomer in Britain, they had a series of programs called "Horizon" which were the American equivalent of the Nova series, and they were excellent, informative programs. I remember being mesmerised by the episodes on the Voyager flybys. Now that was cool!
In the end, if it inspired your kids to look up at the stars, then it has served it's purpose, and I hope your kids keep their enthusiasm and interest, so I can't argue with that. But why did PBS have to do it with something as useless as bloody String theory?!?
Feh. I need my coffee and to stop being a grumpy bastard. Sorry.
Dr Fish
provided new evidence supporting the existence of dark energy, the force
I think Lucas may have a case here...at least to try
submitted by starannihilator
Okay, now you're just ASKING for it!
char *mySig;
These clusters differ in age by 7 billion years. Is it really fair to assume the ratio of hot gas and other things is the same? There are so many assumptions in these things that the conclusions are wishful thinking at best.
Do cosmologists take into account the mass equivalent of all the non-dark energy (light) that is flying around in space? How about the radiation pressure from it? i.e. cassimir (sp?) effect on a galactic scale. Gravity from virtual particle pairs? I'm not saying these things are to blame, but they are all real and sometimes I doubt people even consider them.
Lastly, how does one calculate (as I read Feyman did) the energy density of free space? Link please. I've always wondered what went into that big number.
> our universe is expanding due to some even bigger
> geek having just poured hot coffee in our universal mug.
When you add more coffee to a mug, you are not changing the distance between individual molecules. You simply increase their number. If that were happening in the universe, you would see more stars appearing, or flurries of stars floating around. The distances between the stars would not increase, but would rather decrease because there is space between the stars to add more stars, which is not true in the coffee mug where water molecules take up all the space there is. The situation will change a little if the geek poured water into the mug. Then molecules comprising coffee (don't ask me what they are; I have no idea) would move apart by diffusion.
"The new findings support the theory that the universe will expand forever, provided there is enough dark matter. "
More dark matter = higher gravitational attraction = less expansion.
The reason for this provide in the sibling response.
Here we can clearly see Dark Matter, as illustrated by these red blotches!...I mean....uh.....ahemm....nevermind."
oops
Aw crap, ninjas!
IMHO the greatest loss in modern thinking is the regularity and linear nature used in regards to time. People did not always uses such arbitrary notions of order for time. If perspective is the great truth, why was Ptolemy so wrong? It is just easier looking at a sun centered solar system. Especially early on. Earth centered is not totally incorrect, just more difficult. Why are we all not taught the theories of a galacticly centered solar system? That would be some fun, but not immidiately usefull for working out realitively local planetary motions. Give me infinite mater (dark, regualr, and unleaded) infinite space (true nothingness runs out of space to fill?) and the only thing I need is the time to exist, time to expand, time to repell or attract or how ever you want to look at energy transfer. Instead of new dark energy, is there not a perspective in regards to time that would more easily allow for the same or similar eneries to act differently? In that case would the universe end instead when we ran out of time to use energy in? "Rookie shut up! Your giving me a headache!" -Church, RedvsBlue.com
Moon gives us insight into darkness.
Chandra = moon in indian languages.
Chandra Shekar = one adorned by moon on his self = shiva, the god of destruction.
why shiva? thats a story for some other day.
I think it has become more than apparent that the Universe is stranger than we can think. In space, the farther out we look, the more we find there is to see. It is similar with the sub-atomic world. Well, I'm a pretty strange person and I have decided to post my own strange theory after having read so many other theories that sound like they came from a crack pipe.
Here is my theory, which I present as an open source scientific theory:
Our Universe is the creation of two (or more even) multi-dimensional Universes that have impacted. The impact MDUs contained both shared dimensions and distinct dimensions. Upon impact, the shared dimensions released enormous amounts of energy and compacted. The distinct dimensions remained more or less intact. The center of our Universe is the point of impact. Our galaxy and all others are expanding out from the impact point as the MDUs continue to integrate. We are, to put it simply, inside the MDUs which created this Universe and which continue to feed it's growth.
This theory has some advantages over classical physics. The first advantage deals with the rapid rate of expansion observed in the Universe. The distinct dimensions of the MDUs were not affected by the initial impact. These dimensions continued unabatted and as they are the dimensions we can observe (the ones that survived impact) appear to have come from nowhere (or in this case, from the point of impact).
The second advantage over classical physics is the explanation for why the Universe continues to expand. Quite simply, the Universe continues to expand because the MDUs are still feeding the process. We don't observe this because we are inside the bubble, so to speak. As the bubble grows, we continue to move away from the center of the Universe.
The final advantage is that this does not rule out most of classical theory. Obviously it flies in the face of the big bang theory, but only in principle. The fact that our Universe started at a single point (more or less) is a part of both theories. This is true for other theories as well.
That's it. You can use this theory for any use, including commercial. Just remember where you read it first and cite you source. Thanks for looking.
Heh, and you still wonder why people hate fundamentalist nutters like you. It's weird that fundamentalist muslims and orthodox jews are at each others' throats... You have more in common then you are different
I'm a student at the University of Cosmotology in Berkley, and I think Dark Matter is great!!!
is 1689. You can see an awesome picture of it HERE. It's about two billion light years away and one of the most massive objects in the Universe. It's so massive that those blue arcs in the picture are actually galaxies that are being visually warped by the gravity lensing. The amount of matter required to warp space that much is about 99 percent more than we can see in that image.
For every annoying gentoo user, are three even more annoying anti-gentoo crybabies. Take Yosh from #Gimp for example.
A deceleration period does not contradict my hypothesis. Here's my version of what happened: start with the big bang singularity and explode it. Because all that mass is now gone, space suddenly uncurves and expands outward at the speed of light. All the energy from the explosion is also moving outward in that outward moving space. At first, there is a lot of wraparound and energy density is very high, then it decreases as space expands. At some point it is cool enough for matter to form. Matter is moving outward through expanding space. This matter curves space and begins to slow down space expansion. At the same time gravity starts slowing down the matter's movement through space. This is that deceleration period. At this point space expansion is decelerating and outward velocity of matter is also slowing down. Then stars form and start converting matter into energy, uncurving space. As more and more stars form, space expansion resumes and finally breaks even with the outward movement of matter. This breakeven point apparently occured about 6 billion years ago.
Here it is. And all without a single reference to some mysterious "dark" stuff, which somebody just pulled out of thin air.
And here's what happens next: when the big stars burn out, acceleration will decrease dramatically. Both space and matter will still move outward until the slower stars burn out. Then space expansion will stop and contraction will start as black holes consume energy emitted by all those stars. Then things will be pretty static for a while, with black holes flying around here and there. Eventually, gravity will pull them together and merge them into the big bang singularity, at which point everything starts over.
Now blow the balloon up a little more such that P0 and P1 are 1mm further apart, and thus P1 and P2 are also 1mm further apart (P0 and P2 are 2mm further apart). Then (D=distance, dD=change in distance):
dD01/D01 = 1mm/10mm=0.1
dD12/D12 = 1mm/10mm=0.1
dD02/D02 = 2mm/20mm=0.1
i.e., dD/D = constant. Since the dD occured over the same time for the two distances, you can also write this as
(dD/dt)/D = V/D = constant = K
(This is the Hubble equation, where K=H.)
So, in theory, you could blow up a balloon such that two points are moving faster than c relative to each other (V=c=D*K). Let's see how to do this. The distance between any two points on the surface is D = r*Q (r=balloon radius, Q = angle between the points in radians which stays constant as the balloon expands). The change in distance over time is
dD/dt = V = dr/dt*Q.
The furthest two points can get apart is Q=pi (opposite points on the balloon), hence the fastest relative velocity will be between these points. Let V = c and solve:
dr/dt = V/Q = c/pi
In other words, if the radius of the balloon was expanding at a rate of just under 1/3 the speed of light, two points on the balloon would be moving relative to each other at the speed of light. (This would not only take a lot of air, but the rate of air required would go up with the cube of the radius, so you'd want to do this when the radius is very small.)
Applying this 2D analogy to the 3D universe, it doesn't have to be expanding at the speed of light for two distant points to be moving greater than c relative to each other. But it does have to be expanding above a certain rate to achieve this. If it's expanding slower than this critical rate, no two points can be moving faster than light relative to each other. If it's expanding faster, they can. Since the expansion seems to be accelerating, it seems inevitable that it will happen at some point if it hasn't already.
We should also be able to figure out if it has already happened or when it will. We know the constant H (from the Hubble equation H = V/D). (It's easy to calculate anyway, given the distance to any star and it's measured relative velocity.) If we know the history of the expansion rate we know how big the universe is, i.e., this furthest distance Dmax between any two points. We can then solve the Hubble equation V = H*Dmax and see if it is less than or greater than c.
By the way, I don't think this violates relativity, it doesn't say anything about the rate of expansion of the universe. I think this falls into the "warp" concept of traveling faster than the speed of light, i.e., if you can locally expand the universe fast enough, it appears you are moving away faster than the speed of light, and vice-versa if you can contract it fast enough locally it appears that you are approaching faster than the speed of light. I could be wrong about that though.
Dark Energy = Microsoft
This is just the rest of the universe trying to get away from having to use M$. If you notice, many of findings seem to point to everything moving away from us (i.e. nothing moving towards us, and nothing stationary in relation to our galaxy's velocity.)
As singularities are believed by some to exist at the center of galaxies and suck everything in, maybe Bill Gates is just the opposite for the entire universe! Instead of a "black hole", he would be a "anti-black hole" or "a-hole" for short, that pushes everything else away.
Read about dark suckers.
Where u and v are the velocities of those spaceships, the formula is something like this:
u' = (u-v)/(1+uv/c^2)
Ignorance kills, complacency kills, hatred kills, but usually not the ones guilty of them.
(1) the universe is not expanding at the speed of light (I think that it is less)
All parts of the universe that we can see are moving slower than light relative to us, because we can't see the parts that are moving faster (this is the "horizon" of the observable universe).
We can't determine anything for certain about the parts of the universe that have passed our observation horizon, but if the rest of the universe has the same distribution of velocities the observable part does, then the universe is infinite or near-infinite in extent and the parts past the horizon are moving faster than light relative to us.
As others have pointed out, this can be thought of as being due to motions of space itself, so there is no violation of relativity from relative motion greater than the speed of light. It just means that we can't observe anything past the horizon. The same thing happens at the event horizon of a black hole. One way of thinking of a black hole is to consider space itself to be "sucked in" at the speed of light at the horizon, which is why a photon fired from the horizon will never reach a distant observer despite travelling at C the whole time (ObDisclaimer about this being only one of many possible metrics for describing black holes, and one that can produce misleading conclusions under other circumstances, yadda yadda).
Dark matter will only be like allah to physicists when physicists start murdering those that don't agree with their dark matter theories.
Perhaps the universe is infinite in size and when a black hole gets sufficiently large and in an area of space that is sufficiently empty (too much dark energy) there is a local big bang that fills in that area. The one and only one big bang we talk about is just our local big bang. We don't see all the infinite universe since the really far flung areas of the universe is expanding away from us faster than light travels.
Let us all not forget that the models generated by cosmologists, particle physicists, et.al. have repeatedly been tinkered with when they don't explain events.
Repeat: "This is just a model."
dark energy is completely unlike anything we've seen before.
Well, except that Einstein had already predicted it in his original formulation for the theory of relativity.
my pet machine
It's likely that Einstein's theory is an approximation, a special case of a more complete theory, just as Newton's laws are a special of Einsteins more complete General Relativity.
So I agree with you on that part.
But why would you say we can't study the speed of light properly? It's fast... but not too fast to study. If you bounce light off a mirror on the moon, it takes a few seconds to return, so all you need to do with light to study it is give it a very long path. Did you mean something else?
-pyrrho
That "dark suckers" page makes my personal top-10 list of "Hardest-To-Read Web Sites of All Time".
This moment of crankiness brought to you by Jakob Nielsen.
Sean
I thought it was obvious from the name! And dark matter is actually midichlorians.
- None can love freedom heartily, but good men; the rest love not freedom, but license. -- John Milton
I think Chandra Levy already proved that there is a source of dark energy, which eminates from the house of Gary Condit it Modesto CA ;)
jg
It's gravity. I have a theory for it, but I'm not a respected physicist so I'll keep it to myself so I don't get laughed at.
Rik
If you have a brain tumor, you are likely to have headaches. However, if you have headaches, it is highly likely that It's NOT a tumah!
Finding corroboration for an observation is not nearly the same as finding support for the explanation devised to explain it. Claiming it does requires circular logic. The real conclusion is at the end of the article; the statement that we just may not yet understand enough about gravity is almost certainly true.
"I may be synthetic, but I'm not stupid." -- Bishop 341-B
"This is just a model."
*turns to offending Knight.*
SHHHHHHH!
On second thought, let's not go to the universe. It is a silly place.
Without considering acceleration:
An expansion speed of 100,000 miles per hour = 877e6 mi/year. (1e6 = 1 times 10^6)
Speed of light is 186,000 mi/sec =5.9e12 mi/yr =1 light yr.
Universe is 13 billion years old.
Expansion at 100,000 mi/hr gives 11.4e18 miles, or about 2 million light years.
Expansion at 186,000 mi/sec gives 76.3e21 miles, or obviously, 13 billion light years.
If we are in the middle nearly, we, and the nearest star may not be moving away from each other very fast, but for other bodies, a space ship moving at 100,000 mi/hr may just keep getting further away from its destination instead of closer.
Try to imagine our universe as we know it expanding at an ever increasing rate, and no matter how fast you go or how far you go, you can never run into anything, not even in a trillion years.
It gives one reason to pause and consider that somewhere we just might be missing some important ingredient in our understanding of the universe.
Dark energy? - No big deal!
"let's see" -> "let's say"
"How can anything possibly go faster than c?"
Tachyons do it all the time. Literally. Just as us tardyons with real rest mass have the speed of light as the upper limit of our velocities and luxons with no rest mass are always moving at the speed of light, tachyons with imaginary rest mass have the speed of light as the lower limit to their velocities.
Nobody's found any yet, but the math says they should be there and nobody's figured out how to disprove them, either.
My Dad has the same idea.
He wrote to Stephen Hawking and got a response and a lifetime membership to some university physics publication - sorry I'm a bit short on the details.
Anyway, his theory goes like this:
Instead of having a single 'big bang' and 'big crunch', there are an infinite number of them. As we move out from the gravitational centre of our big bang, we approach other such 'universes' which have their own centre of a 'big bang'. The gravitational effects of our own centre get smaller, while the gravitational effects of other centres get larger, and the same happens for all other parts of our 'universe'.
So instead of some mystical dark matter / dark force which is blowing our universe apart, we simply have traditional gravitational forces at work.
That's what I understood of what he said anyway. He went on for a fair while indeed, and it all sounded coherent.
I like his theory ( and others ) better than the 'dark matter' / 'dark energy' theories, which remind me of the theory of the 'ether' from not too far in the past. When you have to start dreaming up whole families of exotic particles that have never been encountered before and will cost billions of dollars to research, you have to wonder if:
a) Your theories need a major reworking
b) Your motivation isn't entirely scientific
So, does that mean that there exists enough "matter" to possibily offer fuel sources for ships, should man kind ever wonder off that far?
Ya, I know. Odd question. But I would be curious what the speculation is on this "matter".
*laugh* Gads, it's the Dark X of the Month Club :)
If I may be philosophical for a minute...
We have a lot of observations that are pretty close to indisputable: we have spectra from other stars, we have comets visit the inner solar system periodically, there are other planets relatively close nearby. Where a lot of the flux is, is where we attempt to explain how such things got to be, or guess at the meanings or causes of things that we can't directly observe or experiment with.
It's hard to remember sometimes that the assumptions that go into a set of theories could themselves be wrong, and that the theories can support one another without ever actually proving the assumption correct.
Some of the most powerful theories are ones that survive new levels of direct experimentation. Take evolution; regardless of the furor it causes in some circles, it has survived from a period of time where nobody knew what "stuff" caused parents and children to look similar, and successive closer looks all the way up to the various Genome Projects have given it actual mechanisms and even experimental techniques.
The old Greek theory of vision resulting from ray emanations from the eye certainly wouldn't survive the advent of experimental biology, yet in its own time, it was entirely self-consistent (and raytracers behave as though it really were the case :)
It wasn't all that long ago that some theories we take for granted were still being hammered out. Take solar planetary formation. According to Gamow's One, Two, Three... Infinity, one of the major fights was between collision theory and accretion theory. Accretion theory makes so much sense to us these days - so what was the problem?
Well, back at the time, folks doing calculations determined mathematically that a planetary disk would not coalesce, but instead remain like the rings of Saturn. One way around this problem had the gaseous elements being removed by infall into the sun, but this caused profound troubles in that the sun would gain way too much angular momentum.
As it stands, the collision theory (formation from collisions between stars) ended up having more problems, and we ended up with accretion theory, with the lighter elements being blown away by solar wind/radiation pressure. The "Zodiacal Light" is assumed to be the remains of those lighter gases, but of that, we certainly can't be sure.
We can't be 100% sure of accretion theory, regardless, because we can't take perfect pictures of planetary systems in formation over millions of years. It's a good working guess, though - and as a corollary, it implies that most star systems have planets, which we seem to be finding (collision theory required a very infrequent condition, which would make planets rare).
Who knows what else out there is ready to be overturned? Gravity? (current assumption: caused by geometry) Velocity of galaxies? (current assumptions: Doppler is the cause of redshift) The Oort cloud (current assumption: there's a near-perfect sphere of comet nuclei that can be disturbed by passing stars enough to send comets our way, but not enough to distort the sphere... amongst other things ;)
Some cherished scientific beliefs will be overturned in our lifetimes. (Fortunately, of course, this will not stop our electronics and entertainment from working). There's still a hell of a lot more to discover than the "we're nearing the point when we've discovered everything" crew would have us believe.
...and that should be an exciting, not a disillusioning, thought.
Binary geeks can count to 1,023 on their fingers
The Elegant Universe
Everyone wants gravity. It keeps me in my bed so I can sleep at night. It is a force I know. It tells me which way is up, as long as I don't think to hard about my limited perspective. Dark matter, or "the matter still not found" can account for an over abundance of attracting energy in this universe acting between objects with seen and unseen masses. Why do I need it? Just to keep my position on the behavior of energy and objects already observed in this universe? That is all energy except for dark (undefined) energy which is needed to very ungravitationally repulse :p the big bang universe out in to nowhere where there is nothing else beyond. Also, maybe I just can't measure any of this accurately.
Sounds like Flatland. Not that all this isn't fun for the math it provides, but it does sound epicyclic. I am not saying it can't work, but it also looks like an over abundance of math to explain contrary observations all made from one general reference point. We can't even see very well through time. Sub atomic stuff is zoo-y. I mean we haven't even seen that much underwater and we've lived here a while. Is there a problem believing we will need new scientific nomenclature for the greater framing of our known universe?
It doesn't seem so. Huckamania just posted a universal refference point that some like to throw numbers at: The collision of multi-dimensional universes that we have named the Big Bang. Doesn't that seem like a more realistic goal as far as mathematics goes? It's better than constantly fine tuning a single universe. Slap a prime or a one on it, and get ready to start all over, defining dimentions and universes. Good or bad as that sounds I just don't believe the math has an end.
It's like everyone getting excited to see all the numbers flip on 2000's eve. But math keeps going. You will not run out of concrete things to count. If you do look somewhere else. What is concrete is arbitrary. In math the empty set defines our unit value for one. [0] = 1 It depends on what you want to do.
Perspective by its nature broadens. To believe beyond the need for perspective and instead toward the attainment of the final oneness of truth is what leads to things like religion, geonocide, love, and poetries like this sentence.
If you want to work at the edge of known timespace you will have to define that which WAS unknowable. Matter that exists multi-dimensionally therefore attracting across dimensions, beguiling it's mass, taking up more time or more space while producing visible effects in this universe. Sounds like there is solid progress to be made there. Then you go on from there. Not as intuitive as finding the earth's circumfrence by measuring the noontime sun, but someone noticed that. At least you won't have to have "dark" anything. I'm going to sleep now.
"And here I am, using my legs, LIKE A FOOL" - H. Simpson
A google search for "hydrino" brings up a fair bit of commentary on the topic.
The technical paper reads like crackpot material. He takes great pains to pooh-pooh current interpretations of quantum mechanics of electrons, and restates many times that it's "just a theory based on unprovables". That raises a rather large red flag.
More importantly, two problems with his scenario crop up:
I suspect that their proposed changes to quantum mechanics turn out to have very obvious effects on other systems involving electrons (like, say, semiconductors) that are easily shown to not be present, but I don't have the math background to grind through their claims and the materials equations to check this.
A list of skeptical responses to Blacklight Power's claims can be found at http://www.phact.org/e/blp.htm. As these pages set out to debunk the claims, you can argue that they are biased. However, they do make a good attempt to provide reasonable evidence/demonstration.
Summary: Almost certainly a quack. May or may not be a scam for investment money.
This was great news to hear that there is soolid confirmation that we have a lot of physics to learn! As for the quote of another poster..
*Anyway, since it's not very likely that the knowledge of dark matter will have a significant impact on the daily life anytime soon, relax and enjoy the (slow-moving) show.*
Some things take an awful long time, cosmological events are one of them. But considering the amount of stuff we don't know that is staring us in the face, I'd be surprised if we didn't get a lot of amazing info a lot sooner than not. Or consider the ratios in the article.. however you add them up we can only see 4% of the universe and 80% or 90% of everything is made of something we are nearly clueless about!
It means there is a ton of physics we don't know about, and there is probably a lot of dark matter hanging around right here on planet Earth that we are likewise clueless about. With all that material to cover hanging over our heads like a massive midterm exam, it would be stupendously clueless to assume that it will have little to do with us any time soon.
Also we can assume that the other intelligences we expect to be out there already know all this material and are likewise talking to each other on darkphones at the speed of dark while jetting back and forth in their dark-powered darktaxis. Considering the amount of radiation we've been pumping into space announcing our presence it would be a very good idea to assume it has a lot to do with us here and now, it is right up there after good nutrition and education, and if anything we need more people to pay attention to it.
Humans don't live long enough to experience the expansion of the universe.
Not that we can detect with our unenhanced senses, anyway.
Those who sacrifice security to condemn liberty deserve to repeat history or something. - Benjamin Santayana
From what I've read, Tachyons are "unpleasant" to most scientists, in that they might refute a certain version of String Theory, for example, because it requires the existence of Tachyons to works.
Feynman's "Lectures on Physics Volume III" is an excellent first serious text. He is truly a master of explanation. In fact, read volumes I & II if you have the time (classical mechanics and classical electrodynamics).
Wikileaks, no DNS