1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Cosmology: Equation of state parameter

  1. Jun 24, 2008 #1
    1. The problem statement, all variables and given/known data
    Hi all.

    The pressure in a multi-component universe is additive, just as the energy-density is:

    P = \sum\limits_i {w_i \varepsilon _i } \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,{\rm{and}}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\varepsilon = \sum\limits_i {\varepsilon _i }

    But what about w? In the Benchmark-model is w = 0 + (-1) = -1 (we approximate to matter and Lambda), or is it a weighted average, i.e. 0.3 * 0 + 0.7*(-1) = -0.7?
  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted