Slashdot Mirror
Dark Energy May Be Changing
SpaceAdmiral writes "Nature is reporting that Dark energy, the hypothetical energy driving the universe's expansion, may not be as constant as previously thought. According to new research the strength of dark energy may be very different now than it was when the universe was young."
According to new research the strength of dark energy may be very different now than it was when the universe was young.
Indeed. Begun, this clone war has.
The theory of relativity doesn't work right in Arkansas.
it's not as dark as we thought it was?
..that someone shreds some light on the matter.
"I too, sense a disturbance in the Force"
Significant amounts of this so-called, "Dark Energy" have been measured around a certain Redmond, WA campus.
It doesn't say if it gets stronger or weaker..
wtf
#hostfile 0.0.0.0 primidi.com 0.0.0.0 www.primidi.com 0.0.0.0 radio.weblogs.com
...considering no one even knows if dark energy EXISTS.
...extraordinary evidence to support it. I'm not an expert on this
topic (will hear more about it from local experts for sure), but
it doesn't sound a statistically significant claim to me.
For the life of me I can't recall a false study about something...
I think it's about pulsars / neutron star. Astronomers found the
first few pulsars and found them to be aligned in a similar
orientation. This provoked a few new thoughs and fresh ideas
among the community...but later only to realize that the first few
detections happened to be a freak series of coincidence; further
observations revealed that other pulsars orient in many different ways.
Choosing random samples is important here. I'm not sure how carefully
that thought process has been applied here by this author (i.g., that
is what Adam Rees alludes to, I think).
We have to be careful since some people tend to see what they want
to believe in.
I personally hate this whole dark energy thing. Its always this and that, here and there. It seems to me to be a poor attempt at a unified theory. Its trying to bring everything together into one thing and to account for all the oddities out there, but is this really any better than the Greeks accounting for oddities in terms of gods and goddesses? It seems to me that we are only adding increased complexity into an already complex system and we are not significantly increasing our understanding. What we are increasing is more unlikely system. Often, the most simple answer is the correct answer. I can't wait for the next new scientific revolution and the next paradigm shift. I'm bored of this one.
-Da3vid-
"This is an intriguing result," admits Turner. But it certainly doesn't add up to a Nobel prize without further confirmation, he says. "I don't think it's a ticket to Sweden."
Are all scientist doing what they are doing for the Nobel Prize? No wonder the korean cloning fiasco happened.
Clear your mind must be, if you are to discover the real villains behind this plot.
Navicula hydraulica plena anguilarum est. Omnes castelli tuus nostri sunt. Ed elli avea del cul fatto trombetta.
So...brighter means closer. Since that was the result that prompted us to think that the universe is expanding in the first place, I guess this means that the rate at which the universe is accelerating is accelerating.
http://en.wikipedia.org/wiki/Big_RipBig Rip.
I'm sorry. The number you have reached is imaginary. Please rotate your phone 90 degrees and try again.
Didn't we recently conclude that dark matter didn't really need to exist at all?
I have no problem with your religion until you decide it's reason to deprive others of the truth.
Ebony Energy, you Insensitive Clod!
At the end of the day, do we have enough data to be able to say anything about "dark energy" that is anything other than wild speculation?
Because you don't know the power of the Dark Side.
-- javaDragon is an instance of JavaDragon.
He is merely collecting data to disprove the current gravitational model.
He actually believes in Dr. Mannheims Conformal Gravity. An attempt to define
gravity in terms of Conformal Symmetry, which the other three forces observe.
In the theory Dark Energy is just a manifestation of the repulsive component of
gravity. And this force changes with the evolution of the universe. He has just
found proof of this. This would mean that they have discovered something that has
not yet been predicted by the standard model. They have been hard at work to come
up with something that they can predict something that can be proved based on the
observation. The only other significant difference from the standard model is that
in the theory universe is always expanding, and there was no contraction phase.
The observations are not yet conclusive enough on this point.
I sense a disturbance in the force.
According to new research the strength of dark energy may be very different now than it was when the universe was young.
Maybe its just the engineer in me, but isn't it possible that we're just observing some other unknown effect. Something so complicated and exotic doesn't feel right. When it comes down to the math we juggle equations around, fit curves, and re-evaluate until the math yields a good approximation. Math juggling is one thing but I don't think there's a strong case for creating a physical entity for it.
----
Go canucks, habs, and sens!
So...brighter means closer. Since that was the result that prompted us to think that the universe is expanding in the first place, I guess this means that the rate at which the universe is accelerating is accelerating.
I realized that I wasn't very clear when I said this - our current theory of dark energy came about because of a type Ia supernova explosion that was about half of the age of the universe. If the older xray sources are brighter than expected, then this means that the acceleration is accelerating. (If the xray sources had been *younger* and brighter, however, it would have meant that the acceleration was decelerating.
I'm sorry. The number you have reached is imaginary. Please rotate your phone 90 degrees and try again.
There's already a few comments openly questioning and in some cases deriding the concept of dark energy. I think this could well be fallout from String Theory's current fall from grace.
It's looking more and more like String Theorists are on the wrong track. I think this may have bred a new skeptisism in people with regard to the more "out there" physics theories.
The whole debate about Intelligent Design may also be playing a part. There's been a very public question about "what is science". String Theory has already come under fire from this, and it's understandable that some other theories such as Dark Energy might also be brought under the spotlight of a new skeptisism.
This might be stifling for scientists, paticularly those with more outlandish sounding, but still reasonable hypotheses. But ultimately I think it will be good for science. No one should blindly accept any scientific theory without sufficient evidence. And supplying that evidence can only further validate the theory. In this sense, skeptics are good for science.
May the Maths Be with you!
This is the actual press release from Dr. Schaefer.
http://www.phys.lsu.edu/GRBHD/pressrelease/
It seems that the results are very damning to cosmological
constants.
Unfortunately there are no good web sites talking about
Mannheim's theory the only paper that explains a lot of
it is "Alternatives to Dark Matter and Dark Energy" which
can be accessed at http://arxiv.org/abs/astro-ph/0505266
Please stop cutting off your
text lines with inserts. It
takes up vastly more space
than a paragraph with no line
breaks would. As you can see
this comment is taking up far
more horizontal space than it
normally would. If this get's
modded up, it will dominate a
substantial percentage of the
total area of this comments
page. That would be an abuse
of the Slashcode. In Future
please do not insert overly
many line breaks into your
comments. It's OK to seperate
paragraphs using line breaks,
but it's not OK to separate
sentences using them. OK?
May the Maths Be with you!
Looking back
;^).
a dictio-in-terminis/
A lifetime ago, it was observed that the Universe is expanding. A few years ago, Scientists made another shocking discovery. The rate at which the Universe is expanding seems to be accelerating.
Since then, it's been speculated that something called "Dark Energy" is responsible for the apparent accelerating expansion; Einstein's "Cosmological Constant" (which he later called the biggest blunder of his career). It is supposed to make up 70% or more of everything in the cosmos, and IIRC, was supposed to have become the dominant force of nature a billion years or so before our solar system had formed. I suppose it could well be the case, but I am not so sure. I often wonder if perhaps the people involved have missed something obvious. (I am not a cosmologist, so obviously take what I am about to say with a grain of salt
My reasoning follows:
The farther we look into the cosmos, the further back in time we are seeing, as light travels at a finite speed (~300,000 kps). Our best instruments are showing us the Universe as it was half a billion years after the Big Bang, when the Universe was very much smaller, and everything was therfore closer together. I don't recall the exact estimated size, but lets say the Universe back then was 200 million light years across. Did it take light 200 million years to cross that distance? No. It took nearly 13,000 million years (13 billion), because of the Universes expansion.
At what speed does gravitational force propagate through the cosmos? Is it an instantaneous thing, or does it travel at a finite speed, as does light? If in fact the gravitational force travels at a finite speed, then masses at the edges of the Observable Universe would only now be exerting their (now greatly diminished) gravitational forces on each other. Additionally, if the rate of the Universes' acceleration is a constant (doesn't increase over time as with the Dark Energy scenario), then it would appear to us looking back, that the rate increased once the Universe got to a certain size, when it was just too big for the gravitational force to have had enough time to travel between them by that point in history.
I've made a few assumptions there, but until I see anything from a credible source showing my assumptions to be incorrect, I find my scenario to be more likely than "Dark Energy." It's an interesting Universe either way.
-------
The above is slightly modified from when I first posted it on November 17, 2005 @ 5:44 pm
http://cogscanthink.blogsome.com/2005/09/26/contr
--Trent J. Townsend
I wrote on Slashdot about an idea of mine. I called it Proportional Displacement. Basically, the idea was that gravity is not a pull, but rather a push. Instead of matter warping space/time, it's actually trying to displace it and the space/time is actually trying to rush in a fill its own vacuum that matter is creating.
The current theory states gravity is like bowling ball on a sheet of rubber in that matter warps it. My idea is that the bowling ball is half-way exposed in this sheet of rubber along the equator and is trying displacing that bowling ball. But, it's not going anywhere. So, it's stretched around it PUSH the very matter that makes up the ball together.
I know it sounds wacky. But maybe with enough space between matter, it will start to push it all apart. If the matter is close enough, the space around the objects will be displaced toward each other. Think of it like a bell curve. Maybe...that's why galaxies can form, and yet they themselves are being pushed away form each other omni-directionally.
Life is not for the lazy.
Who can the greenies blame this one on then? James Lovelock says it's our fault for all the space pollution from our rockets. It's too late, there's no going back now. In another 200,000 million squillion years the human race is history.
The Universe is angry. Game over man! Game over!
It wasn't that long ago - probably a year or two - that some researchers were claiming that c (speed of light) decreased since the Bang. I was quite skeptical at the time, because changing c is going to change the among of energy and matter in our universe.
Up till today I haven't seen another team confirming this.
So, what you're telling me, Percy, is that something you have never seen is slightly less blue than something else you have never seen.
They whose government reduces their essential liberties for temporary security, receive neither liberty nor security.
almost all major physics theories / forumulas i've come across have been very simple and elegant. With current theories dark matter seems more of a fudge factor to account for what modern physics cant explain.
Retard you are. Trolled and having had a nice day you will be.
Now do you see the folly of driving huge SUVs?
If you were blocking sigs, you wouldn't have to read this.
...what the discussion is really about then for only a moment, pulleaze, ignore the "I hate this whole dark energy thing" or "dark matter didnt even EXIST right?" yadda... and, certainly, this all has little to do with string theory. remember this is observational cosmology, not physics.
it has been reasonably established from several independent observations (cosmic microwave background, supernovae 1a, large scale structure) that the expansion of the universe is accelerating; the universe today is expanding faster than it was in the past.
now, guess what? we *see* it, but dont understand how or why. we only know that all "matter" (baryonic and non-baryonic) attracts, therefore there must be some *repelling* force; out of ignorance, astronomers call this repellant "dark energy". *theorists go wild*
but this is not the point. the real criticism of this study is on the interpretation of the observations. in fact, understanding that requires little esoteric theory, it's quite simple. the essence is that Gamma Ray Bursts, observations of extremely powerful stellar explosions, are used to derive the geometry of the universe. this *can* be done, empirically, if one knows 1) how bright the explosions were intrinsically, and 2) if one knows their distances independently (i.e. through spectroscopy).
BUT... GRB physics is quite messy, so at this point nobody can claim *yet* to know what their intrinsic brightnesses are (such that they can be used as "standard candles"). second, measuring distances requires accurate spectroscopy which is *really* hard, and close to impossible for the most distant and faintest GRBs. third, the current sample of GRB observations with spectroscopy is small.
the main reason why the conclusions/interpretations as published in Nature are disputed is because of these difficulties.
astrosociology: claim what you can as early as you can. if you're right, you're the first and eternal glory is your part, if you're wrong, ppl will forget you anyway.
if you ask me, Nature's standards are slipping...
Maybe the Xeelee are winning their billion-year war against the dark matter photino birds?
I am not a physicist, but, it seems obvious to me that every action has an observable reaction in this universe, and that all things naturally observed are a cycle:
Therefore:
As the universe continues to expand, eventually Entropy will slow down measurably (perhaps not for many millenia, who can say how time works relevant to our current reality? We already know that it is not a constant, but relative.) This will have the effect rather catastrophically of altering everything in reality immediately, and triggering the eventual collapse of the universe, as the end result of the current cycle of expansion.
If the universe is as ordered and logical as we have thus far witnessed, it seems to be likely anyway.
rhY
I hold very few opinions. I hold information based on observation and fact. If you wish to disagree, please use facts.
Another way to see this problem is to consider the speed of light to be changing! This has been Charles Berner's observation in 1967, and I published it on my website 8 years ago. The key insight is that each of us creates the physical universe in order to manipulate others. As time passes, we are learning to trust others more. Therefore our quantum turn, the distance we can move while still interconnected is being extended. Therefore the speed of light is slowly increasing. The effect is geometric, since we all wait for the slowest among us. It is very simple really, if we are willing to wake up to our own true nature.
If you want to read more see http://www.dyad.org/d06twy1.htm
May all of you and yours find the path of peace and love.
Your main problem is that you're just speculating in the air without actually doing the relevant math to tell you whether your idea works or not.
When astronomers find evidence of dark energy, they measure a parameter called the deceleration parameter (q). It's called that because it's supposed to be positive if the universe is decelerating due to gravity, when we thought that was all to speak of. It can only be negative (according to Einstein's equations) if we have something in there that is either dark energy or a lot like it.
You can also determine the amount of dark energy from measuring the curvature of the universe (as the WMAP satellite has done via the cosmic microwave backgroud), and subtracting the portion which has to do with matter (baryons and dark) from other observations.
Either way, you find that you need something other than just matter. You need this dark energy stuff.
it was already suspected that dark matter and dark energy were different when the universe was young, they are both linked to the hubble constant H, which is different the further back in time you go. it might be new evidence i haven't read the paper in nature yet, but its not a new idea
It's almost as if the people who are proposing these explanations aren't willing to toss out the current explanations they have for things and essentially start from scratch. But when you start to kludge explanations together as they have with dark matter/energy, that's exactly what you should do: go back to the drawing board. Having to kludge something is a huge hint that you got something badly wrong somewhere way back towards the beginning.
Obviously whatever you come up with has to explain current observations to at least the degree that current conventional theories do, and current theories then have to become a "special case" of the more general theory, just as newtonian mechanics is a special case of relativity.
Use 'slashdot stuff' in the subject line in any email you send me if you want to get past the spam filter.
Dark Energy Terror Alert: Orange
the fact that our universe's expansion was supposedly accelerating, I formulated an impromptu theory of my own, which is (imo) equally likely and silly. here it goes.
our universe- the big nothing- is surrounded by super-dense matter- the big everything, if you will- and the super-dense matter is pulling everything in our universe out toward the edge. (yes, it did all start in the middle in accordance with the big bang.) i suppose you could call this theory 'the big tear' or 'the big rip', since everything is just being pulled apart.
what's outside 'the big everything', you ask? perhaps we are like one little spherical hole in a sponge, or in a block of swiss. perhaps there are many many other 'verses in their own bubbles.
yup, that's what i'm sticking with.
The power of Christ compiles you.
A Random Blog
That is why it is hypothetical.
2 .html)
"Could Einstein's theory of gravity, which has proved to be correct in all cases so far, be somehow wrong?"
(from http://chandra.harvard.edu/xray_astro/dark_matter
Sure, it could be wrong...something as theoretical can always be wrong. I think the observations that man can make from Earth most likely are bent or distorted by the massive size of the galaxy and the distances between them. Something so huge is hard to measure or calculate definitively.
He who knows best knows how little he knows. - Thomas Jefferson
Mathematics is not a science. It is a tool (an important tool, but a tool nonetheless) that is used in science. Science (from Latin scientia - knowledge) refers to a system of acquiring knowledge - based on empiricism, experimentation, and methodological naturalism. Mathematics is not based on experimentation or empiricism, it is based on deduction and logic.
Also, I don't know how you could argue that physics is not a "hard" science. As the sciences go, one can argue that physics is the "hardest" science of them all, because at a fundamental level, all the other "hard" sciences (chemistry, biology, geology, etc) derrive from physics in one form or another.
Are you completely new here? or what?
There are those who believe that the Universe is guided by the unseen hand of an intelligent creator. Place your faith in God and the miracles witnessed by some and you have Religion.
There are those who believe the Universe is guided by the unseen gravitational forces of Dark Matter. Place your faith in Dark Matter and the miracles witnessed by some and you have Science.
if this dark energy is still a theory that hasnt got any solid proof that it exists, how can you know its different now to how it used to be?
portfolio
In Soviet Russia dark matter changes YOU!
Speak for yourself. I'm keeping my talent points at 31/00/21 for nightfall and shadow burn.
...Eh, nevermind. You would have had to have been there.
You need a FREE iPod Nano
I've seen that claim a lot, but nothing I've found in logic, mathematics, or physics supports it. From what I've seen any claim requires the exact same amount of support as any other claim. However, it seems to be important to you, so let's make a deal. I will grant you the power to require extraordinary evidence for extraordinary claims if you grant me the power to decide which claims are extraordinary.
Or, stated another way, that claim seems extraordinary. May I see what evidence you have to support it?
-Loyal
I aim to misbehave.
A longer article on this in the NY Times says that other astronomers doubt this result.
"Education is not the filling of a pail, but the lighting of a fire." -- William Butler Yeats
it isn't there, doesn't mean it isn't really there.
"There is a theory which states that if ever anybody discovers exactly what the Universe is for and why it is here, it will instantly disappear and be replaced by something even more bizarre and inexplicable.
There is another theory which states that this has already happened."
Even Einstein admitted that theory is theory, and that reality is far more silly than any metaphysical construction made by man. (On quantum theory)
It's epicycles. It's dark matter. It's God vacuuming.
The question is: Whose appendage, exactly, were you touched by? Was it noodly?
Defining Statistics and Social Research
Slashdot: Science for nerds, like dark energy and matter.
"Beware of he who would deny you access to information, for in his heart he dreams himself your master."
A British astrophysicist says apparent acceleration of universal expansion can be explained by add a slight elliptical warp to the geometry of space. Then too, some physicists like Einstein claim warps and accelerations are physcial equivalents. The presence of alternative matter and energy could be causing the warp.
(This astrophysicist keynoted the 2004 SIGGRAPH because his mathematics is widely used in computer graphics.)
So something that is invisible, cannot be directly measured now has to undergo constant changing properties so that it fits theory. The other theories I've heard of that had such problems were heliocentricity, phlogiston and aether.
Occam is rolling in his grave.
No. And that's far from the only comment. Did you even read the thread? (Yeah yeah, I must be new here.) These rebuttals to their (unpublished) paper might help.
Does this mean that Dark Energy is equal to dark matter times the speed of dark squared?
This is completely false. This is not a sig.
just like "Global Warming".
It's all because of George W. Bush!
I'm sure you're in a position to fairly judge the issue.
For the evidence regarding dark matter and some of the philosophical and historical issues behind it, please read this old comment of mine.
Yes, that's exactly it. Dark matter theories exist because astronomers are unimaginative.
I hate to break it to you, but once upon a time, dark matter wasn't a current explanation that astronomers weren't willing to toss out; it was the radical new idea that had to compete with comfortable old notions as well as other radical new ideas, and was met with intense resistance. It gradually won out over the course of decades for the simple reason that more and more evidence amassed in its favor, and none of the competing theories worked as well.
Dark matter was the "back to the drawing board" idea, and was accepted because there is a lot of independent evidence in its favor. Just because you, personally, don't happen to like it does not mean that it's a "kludge".
And to your other response:
This is nonsense. That is not the definition of dark matter. Dark matter is matter that does not radiate an observable amount of EM radiation. You are dark matter, by astronomical definitions. However, most of the dark matter is likely to be some new kind of elementary particle, for various reasons. However, that is not defined to be "unobservable" either. There is a definite possibility (but no guarantee) that such particles can be detected in particle accelerator or cosmic ray experiments, analogously to how other weakly interacting neutral particles (like neutrinos) are detected.
It might be that we can't detect dark matter particles in that way, either because our detectors aren't good enough or because the dark matter particles interact only gravitationally. (Such particles can theoretically exist; see, for instance, "sterile neutrinos".) But influences on gravity are precisely the reason why we believe dark matter exists in the first place.
You say that we cannot detect dark matter, but we detect it precisely by means of its gravitational influences on other bodies. And we detect neutrinos by means of their weak nuclear influences on other particles. Just because we can't see it doesn't mean we don't have scientific evidence for it.
Sure, having an additional way of detecting it would be nice, but it may not be possible. Right now we can't detect gravitational waves in a laboratory, and it's certainly important to try to do so, but we already have good scientific evidence that they exist, because we see star systems losing energy at exactly the rate predicted by general relativity due to the loss of gravitational radiation.
When you get down to it, most of astronomy consists of indirect observations, rather than experiments we can control in laboratories. Are you going to tell us that it is unscientific to postulate a 2.5 million solar mass black hole at the center of our galaxy, just because we can't see it? We can see the gravitational effects of millions of stars compressed into a region of space no bigger th
No, there aren't, though this specious comparison is common on Slashdot. Epicycles made no independent predictions, had no independent verifications, and being essentially "curve fitting", was not falsifiable. (You can describe any orbital motion using epicycles.) Dark matter makes numerous specific predictions, has been verified by a number of independent phenomena, is falsifiable: it cannot be used to describe any kind of gravitational influence.
See this comment for more information.
Now, dark energy has rather less evidence in its favor, so it remains to be seen how things shake out in the end. However, calling it an "ad hoc bandaid" is too extreme. It explains the data rather well and is actually not that complicated a hypothesis (though it may get more complicated in light of new data).
first we don't have it, then we have it, then we don't have it, then we have it again....
First, matter conservation. Yes, I know about entropy, but these particles would have to exist somewhere and, like parent post said, would change the gravity of whatever they were pushing toward. Second, Newton wouldn't allow it. According to Newton the earth pulls on us just as much as we pull on it. I figure it's just some other kind of field like magentics... or God just messing with us.
This is all too much now... it just seems to me that every time science can't figure something out they just give it a name and it makes it all better. Dark matter, dark energy, gravitrons. I've been able to sleep without fully understanding gravity, I should hope you could too. As long as I understand it well enough to keep my blanket on me (with a little friction), and a roof over my head, I feel fine.
This sig isn't original enough, it's time to come up with something witty...
In other words...our best has no clue as to what the universe is held together by...nor do they know how it got here. Genesis clearly lays out how it got here...all one has to do is pray for faith in Jesus Christ and one will receive answers and peace about these situations that 'man' has so tirelessly pursued...even with direct scientific facts staring them in the face that oppose the widely accepted ideologies. The 'Big Bang', or what I like to call, the 'Big Blunder' simply did not happen and there is no sensible way to even speculate that it did. If interested, please explain the many scientific facts that fly in the face of and 'old earth' at this site: http://www.icr.org Please don't just rant without seriously reading some articles here. I'm am very serious. For those whom have ears, let them hear.
Why shouldn't dark energy change? gain and lose power (though i would think lose power)...as it travels, in its wake it leaves dust clouds, atoms, rocks, etc...new things are formed - so where do these new things come from? There has to be something supplying these resources - and if it is coming from this dark energy - shouldn't that be depleting it?
Just my two cents...I guess that I am of the mindset that you can't get something from nothing?
I mod down so you can mod up. Your welcome.
No theory is provably correct. All you can do is fail to disprove them. All you can ever say is that a theory explains the observable results as we can measure them, and that we have been unable to make any observations that run contrary to the theory.
To affirm this principle, BTW, is why the Intelligent Design crazies have to be defeated.
If by 'concluded', you mean 'two minor figures raised the vague suggestion that various unidentified and pretty implausible factors may somehow conspire to explain dark matter, in a study whose serious flaws meant most in the physics and astronomy community ignored them', then yes. We 'concluded' dark matter doesn't need to exist.
t he-clutches-of-the-dark-sector/
http://cosmicvariance.com/2005/10/17/escape-from-
Quoted from the article there....
Let's turn first to the attempt by Cooperstock and Tieu to do away with dark matter. To be honest, there are a bunch of problems with this paper. For example, equations (1) and (2) seem mutually inconsistent -- they have chosen one coordinate system in which to express the spacetime metric, and another in which to express the spacetime velocity of the particles in the galaxy. Ordinarilly, you have to pick one coordinate system and stick to it. More importantly, Korzynski has analyzed their solution carefully and noticed that they have secretly included not only the mass of the stars, but a completely imaginary thin sheet of infinite density in the galactic plane. So the fact that the rotation curves don't decay as they should is really no surprise.
But the real reason why most astronomers and physicsts didn't take the paper seriously is that it violates everything we know about perturbation theory. In the galaxy, there are two parameters that are very small -- the gravitational potential is about 10-6, and the velocity of the stars (compared to the speed of light) is about 10-3. So it would be surprising indeed if perturbation theory weren't doing a really good job in this situation, even just including the first-order contribution. The real reason why nobody paid much attention to Cooperstock and Tieu is that they didn't even seem to recognize that this was a problem, much less offer some proposed explanation as to why perturbation theory was breaking down. Extraordinary claims require extraordinary evidence, and we would need to be given a compelling reason to think that our perturbative intuition was failing before anyone would put a lot of effort into analyzing this paper.
Bear in mind that Nature only joined the cohort of news agencies *reporting* on a 5 minute talk at the recent meeting of the American Astronomical Society in DC. The research in question has not been written up as a scientific article (nor refereed through the peer review process). Many in the community feel that the basis for the claim is not grounded, and in fact is based on flawed assumptions (for instance, some of the relations that the author uses are believed to be instrumental effects and not intrinsic properties of gamma-ray bursts). Even if the statistical analysis is correct, the author has only found evidence for that gamma-ray bursts were slightly brighter in the past (for which there is evidence from other observations) not that the universe is even more wacky than we thought.
A marine I once knew introduced me to the term "Kludge" (he pronounced it KLOOJ). It is a hastily-assembled, inelegant fix to an otherwise fragile construct.
I love physics, but beware any time a physicist says "I've found something that changes/that I can change to fit in my otherwise not-completely-working theories."
This isn't to say it's not true. The universe is peculiar. But beware.
No, I'm not. I already mentioned that type of "dark matter": gas, dust, etc. But there's a crucial difference between that kind of "dark matter" and the type we're talking about. The type of "dark matter" we're talking about does not block light. It's unobservable in any conventional sense.
You clearly don't get what I'm saying.
Dark matter is theorized in order to make our current gravitational theories fit the observed universe. You, and others, claim that the gravitational influence of dark matter is how it's detected. But don't you see? It's because the gravitational calculations based on observable matter don't work that you introduce dark matter into the equation to begin with. You can't add dark matter to the calculations to make them fit observation and then simultaneously turn around and say that the gravitational observations are what confirm dark matter's existence!
When observations don't fit the theory that is supposed to predict them, you toss the theory. The theory in this case is our current gravitational theory. It clearly works extremely well for our local region of spacetime but does not work for the universe as a whole. Whatever replaces it must have the current one as a special case.
There's a big difference between the two. Dark matter is theorized in order to make current gravitational theory fit the observations, and is being "confirmed" by that same gravitational theory. Neutrinos were proposed in order to explain the behaviour of electrons during beta decay. Neutrinos were confirmed not by the behaviour of said electrons, but by another independent and predicted interaction.
In short, the neutrino posulate made a set of predictions that were independent of the observations that suggested the existence of the neutrino in the first place.
That very clearly is not what's happening with dark matter: the "confirmation" comes from the very thing that prompted its postulation to begin with!
Finally, the dark matter theory does not, that I can tell, make any non-gravitational predictions of its own. Unlike the neutrino theory, it doesn't tell us what else we should observe that we haven't already. That alone is reason enough to discard it.
Sure, it's possible that this dark matter exists. But as a theory, it ain't science unless it makes testable predictions. Dark matter by its nature does not -- it's an attempt to force-fit current gravitational theory with current observations. That's why it's a kludge.
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it's the old materialism vs. vitalism "holy war".
Scientists in the persuasion of Materialism believe that the universe is fundamentally composed of matter.
Vitalists maintain that the physical universe is just a very tiny subset of "all that is". Conciousness is primary, the physical universe is the playground that we all are currently occupying.
Matrix terminology: Conciousness is "the real world", whereas the physical universe is "the matrix". The movie was based on buddhist philosophy, so it is an apt analogy.
See Ingo Swann's Psychic Sexuality for more on the age-old Materialism vs. Vitalism debate, from a decidedly pro-vitalist perspective. (Sexuality being, of course, where most of us encounter vitalism-related phenomena).
Learn the rules so you know how to break them properly.
www.teslabox.com
In other words, yes, you are dark matter.
It certainly refracts light, and this has been observed.
It's the other way around.
Of course you can, because there are gravitational observations of many different phenomena (not to mention the electromagnetic imprint on the CMBR) which otherwise would have no reason to be related to each other. Dark matter as observed in galactic rotation curves has implications for large-scale structure formation in the early universe, the cosmic background radiation in the very early universe, it should be responsible for a certain number of gravitational microlensing events, etc. All of these phenomena are observed; without dark matter you have to postulate a patchwork of non-interworking theories to account for each one. Dark matter accounts for all of them in a consistent manner.
We can replace our theory with a different theory of matter distribution, or with a different theory of gravity. Both have been tried. Altering our theory of gravity has not worked to account for all of the observations that dark matter does account for. Altering our theory of gravity, on the other hand, may account for the observations pertaining to dark energy.
That interaction is precisely the weak force. We detect neutrinos only through their weak interactions, and (so far) we detect dark matter through its gravitational interactions. Neutrinos interact via the weak force in various independent ways, and those ways have been confirmed, and serve as independent tests of the existence of neutrinos. Dark matter interacts gravitationally in various different and independent ways, and that has also been confirmed.
The same is true of dark matter, as you would know if you spent even 5 minutes studying the evidence for it.
That is also wrong. There are actuall
Then I stand corrected, and retract what I said previously.
Dark matter "feels" like a kludge to me, but if the theory makes multiple independent predictions that have yet to be confirmed then it's definitely science, and if those predictions wind up being confirmed then it's good science, too.
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Ok, now that you've conceded that, I'll cede some ground too. :-) One problem with dark matter is that there are a number of different dark matter theories, depending on what you hypothesize the dark matter particles to be. So it can be difficult to objectively say that "dark matter" predicts this or that, because it depends on which one you're talking about. However, it's not possible to describe every potential observation by cooking up the right kind of particle, so it's not totally ad hoc. It is, however, not as specific as we'd like it to be.
It's so obvious I can't believe nobody has pointed it out yet.
The reason the universe seems to be changing so much is because we keep making all these damned observations.
Duh.
Hmm...that does complicate things a bit. I'd expect the only real way to narrow it down would be to perform experiments in supercolliders and such.
So do we need to perform experiments in supercolliders and such in order to see the effects of existing particles, or to produce them? If the latter, then one question that naturally arises is why we'd need to produce them when they're theorized to be in great abundance elsewhere in the universe.
That said, I do realize that "great abundance" could easily be a very tiny amount per volume of space, since the distances between galaxies are astoundingly vast.
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I wonder if the changing laws of physics (namely, the magnitude of dark energy) will result in the voiding of the law of conservation of energy, based on Noether's theorem.
Agreed. Someone else said it here too. I'm no expert on this but I never really bought the 'dark' stuff. It seems a bit magicky and wrong somehow. They've probably missed an entire force out or something. I think we're light years from a GUT too. I mean Riemann's hypothesis isn't proven yet - what hope do we have at a GUT?
spoonerize "magic trackpad"
...and yes, black holes indeed are one hypothesized form of dark matter. Dark matter is matter that has gravitational effect but no electromagnetic effect (ie. it's dark), and solo black holes certainly fit that description to a T.
However, as the other responses have mentioned, MACHOs (MAssive Compact Halo Objects, ie. solo black holes, neutron stars and white dwarfs) cannot explain a number of observations. Their gravity will actually lens background stars, which we would be able to detect. The observed number of lensing events is much too small for MACHOs to make up a significant fraction of the dark matter.
Another severe problem is that we don't know of any way to make MACHOs except using baryons, and observations of the ratios of light elements (H, D, He-3, He-4, Li-6, Li-7, Be-8) combined with our knowledge of nuclear reaction rates tells us that the density of baryons is too small for the dark matter to be made significantly of baryons.
But the main point I wanted to make is that you shouldn't say "maybe there's no dark matter, but instead there are lots of black holes that we can't see" - postulating black holes that we can't see is exactly postulating a form of dark matter.
[TMB]
Yeah, what do those nobel-prize winning physicists like Hannes Alfvén know, right? Wiki entry: http://en.wikipedia.org/wiki/Hannes_Alfv%C3%A9n Again, I was just introduced to the plasma cosmology theory a few days ago, so I haven't had time to digest the material, but while I aknowledge it's not widely accepted yet, I think crackpot theory is a bit harsh of a description for a theory supported by acclaimed physicists, professors, and people who have won nobel prizes for their other related theories.
"Can we trust science?"
Author states that two scientists have been found falsifying data. Therefore, scientists shouldn't be trusted until their data can be verified. Wow, that's reassuring, Christians encouraging skepticism. Ever heard of Wurzburg? It was a small town that in 1589 alone, immolated or burned alive 28 heretics, including a number of children, and it was one of hundreds, if not thousands of towns doing so, with the full support of Church infrastructure. Based on your logic, I consider all Christians to be murderers, until it can be proved otherwise.
"The Devastating Issue of Dinosaur Tissue"
Ah, the flagship article. A bona-fide evolutionist finds a T-rex fossil that looks young, and is perplexed. So, every fossil ever found, except for one mentioned in this story, contradicts the creation theory, but you expect to roll back the scientific clock to the dark ages based on this alone. The (lightly) quoted scientist also specializes in well-preserved fossils, and why they are so. She does not make the claim that the T-rex fossil is centuries old, but the author of the article does. In fact, I have dug up a line from her 1997 paper:
Perhaps the mysterious structures were, at best, derived from blood, modified over the millennia by geological processes. [pg: 55]...But more work needs to be done before we are confident enough to come right out and say, "Yes, this T. rex has blood compounds left in its tissues."
So I have a question for you, why don't all T-rex fossils appear to be hundreds of years old? Science seeks to explain natural phenomenon, but you don't, therefore, what you are hawking is not science.
Another article cites an article from New Scientist magazine: Instead of small, rodent-like mammals living in the time of the dinosaurs, evidence has been discovered the a badger-like mammal may have hunted in those times. Curses! There's goes the entire evolutionary model! Also, evidence of grasses in dinosaur dung, though they shouldn't be there! Take that, Darwinist!
I love the RATE (Radioisotopes and the Age of The Earth) conference summary: 8 whole "Scientists" trot out the most bogus theory ever, but really, the bullshit is conveniently packed into this one statement: "Nuclear processes were accelerated during certain periods of earth's history." OH, that's how you get from 5 billion years old to ten thousand. Someone call Steven Hawking, I'm sure he'll be soooooo relieved to find out.
This is the problem with taking creationists to task. Mountains of evidence point to one conclusion, one piece points to an inconsistency, and therefore you claim the theory is unsound. That is not science, and that is not how you win a logical argument. Here's my argument: you are not worthy of the hard-fought victories that science has made on your behalf. Inject a little Jesus into your kids to protect them from disease. Go ask the Bible why Hubble's law works so well.
Incidentally, Georges Lemaître, one of the first physicists to propose the Big Bang model, was also an ordained Priest. He wouldn't let you and your band of Creationist dimwits shine his shoes.
Both options could work, depending on the nature of the particles. Also, we could detect them without colliders by looking at how they affect the decays of other particles (e.g., some hypothesize that some dark matter might be trapped at the center of the Sun and we can look at particles emitted from there).
They would have to be very massive, and thus very difficult for us to produce, but not so hard for the Big Bang to produce them.