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Space Science

Galaxy Clusters' Stunted Growth Confirms Dark Energy 167

Posted by kdawson
from the glimmer-of-fur dept.
A new study of 86 galaxy clusters in the early universe has provided independent confirmation of the existence of dark energy. In its absence, gravity's pull should have caused the number of clusters to increase by a factor of 50 over the last 5.5 billion years. What is observed is a factor of 10 increase. "Together with earlier observations... the new data strengthen the suspicion — but do not prove — that dark energy is a weird antigravity called the cosmological constant that was hypothesized and then abandoned by Albert Einstein as a 'blunder' almost a century ago. If that is true, the universe is fated to empty itself out eventually, and all but the Milky Way's closest neighbors will eventually be out of sight. ... Adam Riess of Johns Hopkins and the Space Telescope Science Institute, said: 'If this was a fox hunt and dark energy was the fox, I think they have closed off another escape route. But there is still a lot of terrain left for the fox, and we've seen little more than a glimmer of fur.'"
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Galaxy Clusters' Stunted Growth Confirms Dark Energy

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  • Re:Logic (Score:2, Insightful)

    by CarpetShark (865376) on Wednesday December 17, 2008 @03:26AM (#26142603)

    Yes, what an impossible thing. To think, that humans, the pathetic little barely-smarter-than-a-chimp creatures on a rock in the middle of nowhere might have... *gasp* limits ;)

  • by ChangelingJane (1042436) on Wednesday December 17, 2008 @03:42AM (#26142675)
    Until they find yet another force we didn't know about, and the model changes again... Hopefully this will keep happening over and over, because all of these different end-of-the-universe theories are morbidly fascinating.
  • by little1973 (467075) on Wednesday December 17, 2008 @04:17AM (#26142829)

    I believe that our knowledge about the universe is quite limited. I can imagine the scientists of the future will laugh about how we could seriously consider dark matter and dark energy. I think it is quite possible that gravity behaves differently over great distances (and I know about the latest "evidence" of dark matter where the dark matter was "imaged" but it is an indirect evidence, there may be other things up in the universe's sleeve which causes this).

    I believe there will be another Einstein who will shed light upon this "mistery" and everything will be simple again.

  • by ghostdoc (1235612) on Wednesday December 17, 2008 @05:05AM (#26143031)

    So let me get this straight...we have Dark Matter because there's not enough gravity within a galaxy to explain the observations, and Dark Energy because there's too much gravity between galaxies to explain the observations.

    Surely Occam's Razor comes into play here? Surely it's obviously simpler to say 'we've got the maths wrong for gravity beyond solar system scale' and start again at the chalkboard?

  • by EdibleEchidna (468353) on Wednesday December 17, 2008 @06:33AM (#26143363)

    Instead of proving the existence of Dark Energy, perhaps what this finding really does is prove that our models are wrong.

    I often wonder if we're looking in the wrong place for an explanation...flaws in our cosmology sound more plausible to me than weird forms of matter and energy.

  • Re:blunder (Score:3, Insightful)

    by martin-boundary (547041) on Wednesday December 17, 2008 @06:53AM (#26143445)
    Democritus didn't have an "atomic theory", what he had was merely metaphysical speculation.

    With the technology available in his time, not only was it impossible for him to verify atomism, but in fact if he had tried to do so experimentally, then the only reasonable conclusion would have been that atomism is highly unlikely, since matter can easily be subdivided indefinitely to the limit of visual perception. As such, steadfastly maintaining the truth of atomism would mark him out as a crackpot nowadays, although in his time the standards of rigour were of course much different.

    Democritus' atomism was an ancestor of atomic theory in the same sense that "a broken clock is right twice a day".

  • by Zdzicho00 (912806) on Wednesday December 17, 2008 @07:05AM (#26143491)
    Heim Theory got Simple explanation for that. Every field got "field mass" associated with it:
    http://www.engon.de/protosimplex/posdzech/px_g_gravi1e.htm [engon.de]

    Because of equivalence of mass and energy Heim says there must also exist a field mass of the field energy of each field. However in case of gravitational field this results in a secondary (very weak) additional gravitative source because a field mass possesses its own gravitational field.
    In a volume V0 there is mass which may be distributed in any kind. This mass is producing a gravitation effect, as it can be described with Newton's approximation. Now Heim says that to the energy of this gravitational field corresponds its own field mass. This field mass again produces a second additionally gravitational field which is very weak. Again this field possesses its own field mass which produces a field. So you receive an infinite series, which however converges very fast against a calculable limit value.
    The whole description results in a short mathematical description for a corrected gravitation law, which corresponds with Newton's gravitation law within the observable area of space. However for very large distances it will provide completely different results. As you can see in the illustration below for very long distances gravitation will produce a weak repulsing force which will only exist if a mass is moving toward the center of the gravitational field. Among other things the phenomenon of the cosmic red shift can be explained now as a gravitational effect.


    /Joss
  • by Kjella (173770) on Wednesday December 17, 2008 @07:15AM (#26143533) Homepage

    Surely Occam's Razor comes into play here? Surely it's obviously simpler to say 'we've got the maths wrong for gravity beyond solar system scale' and start again at the chalkboard?

    Well, from what I've understood adjusting the constant of gravity would explain some things but would make other predictions incorrect again. All in all, dark matter / dark energy is causing less headaches than the opposite, so unless you can pair it off with some other theory to make the world right again it won't get accepted.

  • by firmamentalfalcon (1187583) on Wednesday December 17, 2008 @09:17AM (#26144039)

    Isn't dark energy a general name for whatever it is that causes our universe do things that aren't explained by our equations?

    So I guess this confirms Dark Energy even more because it invalidates even more equations than before. So it isn't the old equations that are wrong; it is only because part of the equation does not include variable D.

  • by Anonymous Coward on Wednesday December 17, 2008 @10:39AM (#26144945)

    Instead of proving the existence of Dark Energy, perhaps what this finding really does is prove that our models are wrong.

    Those statements are semantically equivalent. Scientists aren't in the business of saying whether X or Y exists, leave that to the philosophers. A scientist can say that "X is a useful way to model the world", but Y might be another way to look at it that ends up with more or less the same math. And then when our tools are good enough to try and tell the difference between X and Y (if there even is one!) we go probe it and move on.

    Scientists *model* reality, not discover or declare it.

  • by Abcd1234 (188840) on Wednesday December 17, 2008 @12:18PM (#26146515) Homepage

    I have to agree with ghostdoc. IANAP

    Obviously. If you were even passingly familiar with the area, you'd realize that a) people *have* been re-examining the orthodoxy (see MOND, among other things), because, you know, some scientists are as smart as you (or perhaps even smarter) and realize that it's an interesting area of research, and b) no one has found an alternate theory that explains the current set of observations (see the Bullet Cluster, and some even more recent results).

    Honestly, what is it with laymen who somehow believe that *they* have some insight into an area that those who've been studying it their entire lives do not?

  • by Abcd1234 (188840) on Wednesday December 17, 2008 @05:15PM (#26150957) Homepage

    Yeah, if the history of physics has shown us anything, it's that laymen have never had any special insight into areas that professional physicists do not.

    You really need to educate yourself if you honestly believe Einstein, a man who graduated in 1900 with a physics degree from ETH Zurich with a physics degree, was a layman.

  • by Abcd1234 (188840) on Wednesday December 17, 2008 @06:22PM (#26151931) Homepage

    Are you saying he was secretly a professional physicist

    Do you even know what a "layman" is? Here, let me explain: It's someone who is uneducated in the subject manner about which he is speaking.

    Einstein was *not* a physics layman. The man was formally educated in the topic!

    He wasn't a layman like you and I are, but he was hardly a member of the physics establishment.

    Fair enough, but my comment wasn't directed at people who are both educated and outside the establishment. It was directed at *laymen*. People who are *not* actually educated in the field they're discussing. You know, people like your neighbour who tells you global warming mustn't be happening because it's cold outside, or because the sun is really just getting hotter but the scientists are apparently too dumb to notice.

    In short, you are, at best, missing my entire point. At worst, you're manufacturing an argument for kicks.

Byte your tongue.

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