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New Light on Dark Energy

  1. Dec 17, 2008 #1
    The Chandra X-Ray Observatory has revealed that galaxies aren't accumulating lots more matter over time:



    http://blog.newsweek.com/blogs/labnotes/archive/2008/12/16/may-the-dark-energy-be-with-you.aspx [Broken]


    This is then attributed to the effect of "Dark Energy", more properly identified as Vacuum Energy, or Einstein's Cosmological Constant.

    So to me, this means that not only can a large mass have significant gravitational force, but even a large span of empty space can have a large gravitational force associated with it.

    So how can we then make use of this knowledge?
    I recognize that one practical implication is that the universe is not slowing down in its expansion, but could keep going indefinitely.

    And then what?
    I remember some experiment by researchers at UC Riverside, showing that the Casimir Effect from vacuum energy could be turned into a nano-sized spring-device. They had 2 corrugated surfaces placed close to each other, at some miniscule separation distance, and the Casimir Effect caused the apparatus to behave like a spring.

    Is Dark Energy considered to be physics beyond the Standard Model, if it's merely confirming Einstein's original conjecture on the Cosmological Constant?
    Also, does this then diminish the need for Dark Matter to explain the observed nature of the universe?
    Last edited by a moderator: May 3, 2017
  2. jcsd
  3. Dec 18, 2008 #2


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    Its yet another piece of evidence that confirms the now standard lambdaCDM scenario 'the concordance model'. Eg ~74% dark energy, 22% darkmatter and 4% regular visible matter.

    Dark energy and Dark matter are both presumably physics beyond the standard model of particle physics.
  4. Dec 18, 2008 #3
    In which case, what are the speculative conjectures about what's causing the Dark Energy effect? In the case of Dark Matter, we have WIMPs as an imagined animal. What does the Dark Energy consist of?
  5. Dec 18, 2008 #4

    I'd like to also ask, how can we compare Dark Energy, Dark Matter, and Regular Matter on a common scale? Aren't they all like apples, oranges and grapes?

    Is gravity the common means of measurement?

    If regular matter and even dark matter exhibit conventional gravity, then what do we call the force shown by dark energy -- antigravity? Is it working to keep matter apart, or is it just working to stretch out the space that lies between matter as much as possible?
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