The cosmic horizon

Discussion in 'Physics & Math' started by stef 730, Feb 5, 2002.

  1. stef 730 Registered Member

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    19
    Here is an excript from Serge Brunier's Majestic Universe:

    ''An object indicates its existance by the radiation it emits, which, like electromagnetic radiation, propagates at 300,000 km/s. At every moment, our vision of the world is thus limited by a horizon, which is expanding, ever since the big bang at 300,000 km/s. So, one second after the big bang, the horizon for any individual point in the universe lay at a distance of 300,000 km. This cosmic horizon moves infinitly faster than the expansion of the universe. Which is another way of saying that with every second that passes new regions of the universe appear that were never connected in the past. Yet present day cosmic structures show that there must have been an extraordinary homogeneity in the past, that cannot be expressed in equations. How could different regions of the universe, never in conatct with one another, 'pass the word' to one another so that their characteristics were exactly the same at the instant their cosmic horizons coincided, and they came in contact? Why also was cosmologogical background radiation emmited when the universe was 300,000 years old?''


    I was wondering what you smart guys had to say about this and if you could explain it a little more simlpy.

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  3. Mr. G reality.sys Valued Senior Member

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    It takes time for light to carry its information to us from distant locations within the Universe.

    The light from many such locations needs still more time to reach us before we can know what information it is carrying.

    From here to the Horizon is what we know. What we don't know lies beyond the Horizon, for the time being.
     
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  5. Boris2 Valued Senior Member

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    Hi stef 730

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    This page might give you some understanding of why, though there is probably no "simple" explanation.

    http://nedwww.ipac.caltech.edu/level5/Guth/Guth4.html

    you could also check out the previous pages etc, there is some maths but I think by reading the descriptions you may get an idea.
     
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  7. Mr. G reality.sys Valued Senior Member

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    The extraordinary homogeneity that established the identical initial conditions for all points in the universe was the pre-Big Bang singularity that appears to have contained them at T=0.
     

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