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B Some more basic questions on Dark Energy

  1. Aug 3, 2016 #1

    rede96

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    Firstly, let me apologise if my questions below are a bit elementary, stupid or if the answers are obvious. But I was curious and wanted to understand a bit more about dark energy from a very layman's point of view.

    So I had some fundamental questions around dark energy I wanted to ask:

    1) What ever dark energy is, I am assuming it isn't something that was newly created post big bang but has always been present in the universe. Is that correct?

    2) Are there any theories that dark energy could be what is responsible for the baryon asymmetry? In other words that some how the missing anti matter was converted into dark (or anti) energy?

    3) Linked to question 2, I take it dark energy isn't the same as normal energy in that it can't be converted into other forms as normal energy can? (e.g. E=MC2)

    4) Could dark energy be linked to the inflaton field in inflation theory? Or could it be the same thing? Could dark energy be responsible for the very early initial inflation? (around 10−35 to 10−34 seconds I think)

    5) This is probably a really stupid question, but thought I'd ask it anyway. As I understand it as the universe expands, more dark energy is created. Simply because the energy density doesn't change but there is more universe, hence more dark energy as expansion takes place.

    But is it possible that the total amount of dark energy in the 'universe' doesn't change? E.g. it was always there to begin with but somehow expansion just reveals it, and doesn't create it?
     
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  3. Aug 3, 2016 #2

    PeterDonis

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    We don't know for sure. Our best current model is that dark energy is a cosmological constant, which would always have been present. But we don't know for sure that that model is correct.

    Not to my knowledge.

    We don't know.

    Probably not but we don't know for sure.

    Not as it is, because its energy density is much too small. If dark energy is the remnant of the inflaton field, the energy density in that field would have had to change drastically at the end of inflation. (Inflationary cosmology says that must have happened anyway--when inflation ended, the energy density in the inflaton field was transferred to the Standard Model fields, i.e., to leptons, quarks, and gauge bosons. The question is whether that left zero energy density in the inflation field--which is our best current model--or some very small positive energy density in that field, which could be what we see today as dark energy.)

    This isn't really well-defined, because according to our best current model, the universe is infinite in spatial extent, so there is no well-defined "total amount of dark energy" in it. The only thing that is well-defined is the energy density, which is constant (as best we can tell).

    Not according to our best current model, because "the total amount of dark energy" isn't well defined. See above.
     
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