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

What can the Anthropic Principal predict?

  1. Oct 9, 2015 #1
    I am curious about how the Anthropic Principal could in principal be used to constrain possible values for physical constants. It seems plausible to me that quite a few physical constants are constrained to be within a few orders of magnitude of measured values, but that is just a guess. I would much appreciate seeing some discussion about which physical constants are so constrained, and which are not, and why.

    Here is an example of the kind of discussion I am looking for.
    If the cosmological constant were much larger, galaxies, or even clusters of stars would not be able to form since the expansion of the universe would move far apart mass concentrations that would form separate stars. Therefore, when a supernova occurs producing many atom types, these atoms would not be able to form solid planets around a newly forming star. Therefore, there would be no warm planetary surfaces on which life could evolve.​
  2. jcsd
  3. Oct 9, 2015 #2


    User Avatar
    2017 Award

    Staff: Mentor

    For life as we know it, the constraints are much stricter, sometimes as narrow as 1%. See the Wikipedia article. Different values lead to a completely different universe which might allow different types of life.
    There could be some yet unknown reason why the fundamental constants have to have their value (then it is clear why they are like that), or there could be different "universes" with different values (then life just exists in those that allow life).
  4. Oct 9, 2015 #3
    Hi @mfb:

    Thank you for your prompt and helpful post. The Wikipedia reference looks quite interesting.

Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook