Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

I Influence of Dark Energy and curvature in photon-baryon fluid?

  1. Aug 17, 2017 #1
    When I read explanations about the early Universe and the oscillations of the photon-baryon fluid before recombination, effects of the cosmological constant and of the curvature of the Universe on the fluid are never discussed. Only dark matter, baryons, and photons are mentionned.

    Dark energy and curvature have no impact on the fluid ?

    I'm just looking for a simple answer, with at most some qualitative explanation if someone has that. The maths involved in the baryon-photon fluid oscillations are quite hard to tackle for me.
  2. jcsd
  3. Aug 17, 2017 #2


    User Avatar
    2017 Award

    Staff: Mentor

    If dark energy is the cosmological constant, it is completely negligible in the early universe.
  4. Aug 17, 2017 #3


    Staff: Mentor

    As @mfb said, dark energy is negligible in the early universe; the reason is that its energy density is so small. The energy density of dark energy is constant as the universe expands, so it was the same in the early universe as it is now; but the energy density of baryons and photons was much, much larger.

    By "curvature", do you mean spatial curvature? If so, it is zero in our current best fit model; that's why it doesn't appear in the explanations you are reading.
  5. Aug 17, 2017 #4
    Thanks for the answers.
  6. Aug 17, 2017 #5


    User Avatar
    Science Advisor
    Gold Member

    Furthermore, if dark energy is not a cosmological constant, it still has to be negligible in the early universe. Otherwise it would disrupt Big Bang Nucleosynthesis, leading to a different mix of light elements in the early universe.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted