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

How do we determine the production of H and He during BBN?

  1. Jan 3, 2013 #1
    How do we calculate how much H and He is created during Big Bang Nucleosynthesis?

    Wikipedia states that regardless of some initial conditions during BBN, it will always be that 74% of the universe is H and 24% of the universe is He, plus or minus a couple percent. How is this determined?

    Sorry - I know this question is fairly basic.
  2. jcsd
  3. Jan 4, 2013 #2


    User Avatar
    2017 Award

    Staff: Mentor

    I don't think there is an analytic approach, but you can simulate the conditions after the big bang numerically with different parameters. With known cross-sections for the different processes at different energies, you can simulate nucleosynthesis.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook