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Beyond CMB

  1. Apr 11, 2008 #1
    Is it accurate to say:

    The Light-Year distance from earth to the Surface of Last Scattering (= CMB location) EQUATES TO the Age of the Universe (13.73 Gyr)? (ignoring units conversion factors).

    Would an observer, say 13.0 G Light-yr from us, ALSO see the CMB the same distance away?

    Where is our Particle Horizon thought to be located, relative to the CMB? (Or Cosmological Horizon, whichever is greater).

    Is it presently thought a significant portion of the Universe lies beyond our Particle Horizon? If so, would not at least a part of that portion have to be OLDER than anything we can observe, including the CMB?

    Thanks in advance for everyone's time and thoughts!

  2. jcsd
  3. Apr 11, 2008 #2


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    You are off by about a factor of 3, Carl.

    The present distance to the last scattering surface is estimated to be about 45 billion LY.
  4. Apr 11, 2008 #3
    45 Glyr

    Thanks, Marcus.

    Is that number only theoretical, or is there some obsevational data to support it?

  5. Apr 12, 2008 #4


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    That number is theoretical, Carl. It is possible the universe is larger than we can observe, but irrelevant. The unobservable portion, if any, will be forever unobservable. Such theories appear suspiciously similar to a temple priest fishing for disciples.
    Last edited: Apr 12, 2008
  6. Apr 13, 2008 #5


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    This comes from observations, and the theory that has been developed given those observations. You can't directly point a telescope somewhere and find this kind of information. This, and related things such as the age of the Universe are always 'theory dependent', so if a different theory comes along that also explains the observations, but is favoured for some other reason (or by newer data) then these 'theory dependent' numbers change, even though the observations don't. Therefore you can't say they are determined either by theory or observations alone, the combination of the two is what defines these types of quantities.
    Last edited: Apr 13, 2008
  7. Apr 14, 2008 #6
    Older than the Universe?

    I understand all the underpinnings, thanks, guys.

    But now I am a little confused:
    If the age of the universe is thought to be 13.7 Billion Years, and nothing can travel faster than light, how can anything be more than 13.7 Billion Light Years distant? This just seems logically impossible.
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