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

Complete photonic view like the CMBR version

  1. Jun 6, 2010 #1
    Ignoring what we know. I was curious as to if anyone had overlayed all of the spectrum's of light on top of each other in a complete photonic view like the CMBR version, only with a much more varied scale, that being the entire light spectrum. And if so what did this produce? I only ask because I was thinking of Olber's shell model that he used in his paradox to decide whether or not the universe was infinite. And if this picture did or didn't produce an infinitely bright view, whether or not this would be sufficient evidence of the universe being infinite or not. Of course taking into account the flaws in his model, and also the time delay for photons of light to reach us since looking in particular at the CMBR, clearly large amounts of these photons are a lot older then those reaching us now.
  2. jcsd
  3. Jun 6, 2010 #2
    Re: Olber

    I don't know the answer to your specific question, but I think it's generally agreed that the distribution of matter through space is finite, but whether space it's self is infinite is probably open for debate.
  4. Jun 8, 2010 #3
    Re: Olber

    How can you tell if the distribution of matter throughout space is finite since you can't tell if there is anything beyond the light horizon of our universe, say another preexisting universe that isn't running parallel?
  5. Jun 8, 2010 #4


    User Avatar
    Science Advisor
    Homework Helper

    Re: Olber

    The observable universe is finite (about 90Bn lyr accross) with a finite amount of matter in it.
    whats beyond the obsevable universe doesn't matter
  6. Jun 8, 2010 #5
    Re: Olber

    Well yea, but how do you know that the universe expands with the event horizon and doesn't go beyond it? And therefore there is something, anything, beyond that horizon that is undetectable to us? Saying "what's beyond it doesn't matter" isn't exactly helpful if say it can enter back across to our side of the horizon?
  7. Jun 8, 2010 #6

    D H

    User Avatar
    Staff Emeritus
    Science Advisor

    Re: Olber

    Olber's paradox implicitly assumes a steady-state universe of uniform density that is not expanding. That the sky is not the temperature of a star is necessary but not sufficient evidence of the Big Bang theory. While the dark sky we see at night is one piece of confirming evidence of the finite age of the universe, it is not conclusive evidence. For example, an infinite universe of infinite age could also have a dark night sky if that infinitely sized/infinitely old universe was expanding or if that universe was not of a uniform density.
  8. Jun 8, 2010 #7
    Re: Olber

    Ahh ok that makes much more sense. Thanks D H
  9. Jun 13, 2010 #8


    User Avatar
    Science Advisor
    Gold Member

    Re: Olber

    Olber's paradox remains a powerful argument the universe is observationally finite. It tells us nothing about any unobservable parts - which is pretty unsurprising.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Complete photonic view like the CMBR version
  1. Static CMBR ? (Replies: 3)

  2. CMBR and space (Replies: 2)