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Proportion of energy compared to mass in universe

  1. May 3, 2012 #1
    In Wikipedia article dark matter, there is a picture that shows us the proportion of matter and energy in the current universe - CMB.

    It seems to suggest there is nothing that exists as energy form except dark energy - which we are yet to see - and every observable exists as matter forms.

    Is this correct interpretation?

    Of course, I know that matter's mass can be converted into energy by Einstein's basic and famous equation.

    If every observable exists as matter, is energy always converted to matter after being converted into energy from matter?

  2. jcsd
  3. May 3, 2012 #2


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    The names "Dark Energy" and "Dark Matter" seem to imply that both are essentially the same, one in the form of energy and the other in the form of "matter".
    That's not true, they are just - unfortunate, btw - names. Both things have nothing in common, and they are certailny not different form of the same substance.
    One does not discern "matter" and "energy" in cosmology. Both are called "mass-energy" in the Wiki article you cited.
    The relevant equations all work with "energy density" for all constituents of the universe, which includes e.g. thermal energy.
  4. May 3, 2012 #3
    no...for a better overall perspective see this brief discussion:

    I forget where I got the following..maybe from post in these forums:

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