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Cosmic background radiation?

  1. Jun 7, 2005 #1
    Problaby a silly thought but if the cosmic microwave backgroud radiation got created in the big bang and travelled outwards at the speed of light, and so did everything else, but travelled at less than the speed of light, would'nt it be "ahead" of us. Or alternatively if the radiation is absorbed and reemitted alot does it get affected by fluorescense, or absorbtion into kinetic energy.
  2. jcsd
  3. Jun 7, 2005 #2


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    Welcome to these Forums BigMacnFries!! (Actually I can't stand them myself!!)
    Where is the Big Bang? we might ask, and the answer is everywhere! All points in space have expanded from the Big Bang equally, they have all expanded from each other, there is no centre, it is space itself that has expanded. Now the CMB has filled all space and radiated throughout it. The radiation is not 'ahead of us' but surrounding us. The universe is filled with a warm (if you call 2.7oK 'warm') bath of radiation and it comes to us equally from every direction (isotropically) -well not quite isotropic but that is another story!

    I hope this helps,

  4. Jun 7, 2005 #3
    The CMBR is not like a gas in thermal equilibrium. Rather it is much like the light from a galaxy, or any other object. What we are seeing is highly redshifted radiation emitted by matter 300000 years after the big bang, just before this matter cooled enough to become transparent.

    If you want to understand how the radiation can have taken so long to reach us then have a look at
  5. Jun 9, 2005 #4


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    Welcome to PF, BigMacnFries!
    As noted above, the Big Bang was not an explosion of matter and energy into space. It was the rapid expansion of all-space. From the beginning, energy and the building blocks of matter were already everywhere throughout the universe. As space continued to expand, this 'plasma' cooled enough for the building blocks to form atoms (like hydrogen, helium). Then gravity pulled this matter together to form stars & galaxies...simultaneously throughout the universe. So, things were not shot out across the universe...rather, the state of the universe and the stuff in it changed over time.
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