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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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  • blunder (Score:5, Interesting)

    by sstory (538486) on Wednesday December 17, 2008 @03:00AM (#26142489) Homepage
    (Sigh). Everytime I see a story about the cosmological constant I have to see the obligatory "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." as if Einstein was so smart he predicted dark energy 100 years ago. No. He put a term in the equation to stabilize the universe, which was then thought to be static, against gravity. Then it turned out the universe wasn't static, it was expanding. That was the blunder. If there's an outward force, as there now seems to be, you'd put a term in the same place. But it's based on new data. I'm sick and tired of the "Aha! Einstein was right all along and he didn't even know it!" comment that has to be stuffed in every cosmological constant story these days.
  • by wolfie123 (1331071) on Wednesday December 17, 2008 @03:11AM (#26142541)
    And I who thought that theories cannot be confirmed by real-world observations, only supported. ...as the blurb also mentions, actually.
  • by cnettel (836611) on Wednesday December 17, 2008 @08:09AM (#26143779)

    Well, if we are able to go about it in a totally different way, that the dark matter/energy estimates weren't ad hoc-adjusted to fit, and we still see that those estimates fit, it means something. It might be something else, including a weirdness in gravity, but overall the data fits well with something that is quite similar to matter.

  • by jandersen (462034) on Wednesday December 17, 2008 @08:48AM (#26143897)

    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?

    Which is, in effect what we are saying. However, it makes little sense to simply scratch the whole, current understanding of the world and start over; introducing an assumption that gravity behaves differently outside a certain distance begs the question why it should be so, and we don't have any compelling answer to that.

    My own favourite, which admittedly comes out of thin air, is that negative gravity corresponds to negative mass. If you look at the classical equation as a rough approximation, you'll see that a negative mass should repel a positive mass, but attract another negative mass. Intuitively this seems to potientially explain the "dark energy" phenomenon, and it might explain how, at the beginning, mass seems to have been created from nothing - perhaps an equal amount of positive and negative mass was created, so that mass was preserved, in total, and then it exploded apart. How about that for an explanation?

  • Re:Logic (Score:3, Interesting)

    by MindKata (957167) on Wednesday December 17, 2008 @09:08AM (#26143999) Journal
    "In either case dark matter may not be necessary at all"

    I agree dark matter may not be the correct answer, but more like, the current best fit answer, given current available evidence. One concept that could explain what is going on, without the need for dark matter, is the idea of Dark Flow.

    If Dark Flow can be proven, (big if?! ... Instant Nobel Prize winningly big if?!), but joking aside, if Dark Flow can be totally proven, then it would mean our idea of the universe, is simply only based on our visible part of the universe. (Due to the limit of how far we can see, because light can only travel so far, in the time the universe has existed). If Dark Flow really exists, then it means we are like a fish in a fish bowl, trying to make sense of the fish bowl, but unable to see beyond the bowl. (So unaware of just how much could be outside the fish bowl).

    If Dark Flow really exists?, I think that would give us an awesome insight into the universe, but also an awe inspiring glimpse of just how limited our understanding of the universe may actually be?.
    http://en.wikipedia.org/wiki/Dark_flow [wikipedia.org]
  • Re:Logic (Score:3, Interesting)

    by maxwell demon (590494) on Wednesday December 17, 2008 @01:11PM (#26147451) Journal

    It also interacts with the photons we can see. Otherwise, the refractive index of air would be exactly 1, instead of 1.00029

  • by tsobo (828580) on Wednesday December 17, 2008 @04:51PM (#26150629)

    Yeah, if the history of physics has shown us anything, it's that laymen have never had any [wikipedia.org] special [wikipedia.org] insight [wikipedia.org] into areas that professional physicists do not. They should stick to their own line of work, like clerking at the Patent Office. Sheesh.

    While this guy didn't have anything new to add, people who've been studying something for their entire lives tend to not be the ones that successfully overturn the orthodoxy. Einstein himself fell into the orthodoxy, and published very little of significant value after 1916--unless you count the EPR thought experiment, which advanced physics greatly, but only by being proven wrong.

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