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I Is dark energy like gravity?

  1. Jul 12, 2016 #1
    Is dark energy an actual thing that can be collected or is it more like gravity, is exists but it's not really an object?

    Is there anything about dark matter / energy that is agreed upon by scientists or has nothing about it been confirmed at all?
     
  2. jcsd
  3. Jul 12, 2016 #2
    Dark energy might be a 5th force. I've also heard it might be how gravity works at large distances (it becomes repulsive instead of attractive).
     
  4. Jul 12, 2016 #3

    Chronos

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    The best we can do with dark matter/energy is to say what it is not. Dark matter is not like ordinary matter because it does not interact via the EM force with anything else [to the best of our knowledge]. Dark energy is not like ordinary energy because it not the consequence of gauge boson interactions [again, to the best of our knowledge]. That may raise the question, 'well, what about gravitational energy?'. The short answer is we don't know much about gravity either, other than it arises wherever matter or energy exists, it is the only force known to be strictly attractive, and it too is not known to be mediated by a gauge boson. The other three fundamental forces swing both ways [attractive and repulsive]. It is therefore logical to suspect dark energy could be the repulsive twin of gravity, especially if gravity proves to be mediated by boson.
     
  5. Jul 19, 2016 #4
    Dear iDimension,

    Dark energy is an infortunate name, as physicists so frequently love to do. It's synonimous to the expansion of the Universe, about whose causation we know nearly nothing, but the name helps to confuse the theme with the well known concept of energy and so promotes much desne cessary misunderstanding.We infer its existence from a supposed acceleration of the expansion of the Universe, that seems to me yet no convincingly comprovated. The existence of dark matter is nevertheless well established to my satisfaction, but not yet identified.
     
  6. Jul 20, 2016 #5

    Bandersnatch

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    <<Mentor note: Reply to deleted post removed>>

    It isn't, though. You can have expansion without dark energy, and in fact the expansion models prior to late 1990s did not include it. What it does is cause the expansion to accelerate after a period of deceleration.

    It's not 'supposed' - it's been well established through observations over the past two decades. See the WMAP and PLANCK results. A Nobel prize was awarded for its discovery.
     
    Last edited by a moderator: Jul 20, 2016
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