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Eh? Please enlighten an idiot.

  1. Oct 27, 2007 #1
    I'm an idiot as far as this sort of thing goes, so I'd appreciate the tolerance due to the stupid.

    I read in the Economist this week that it is now possible to look so far into space that we can see the universe as it was only 300,000 years after the big bang, when the first stars had yet to coalesce. I understand that the farther we look, the further back in time we look, because light has taken time to reach us.

    However, I assume that 300,000 years after the big bang our own star, the sun, had yet to coalesce, and the material for it was in that material we're looking at now.

    How can this be? Our star, and us, are here now. The material that makes us must have travelled from what we are looking at through our telescopes to where we are now, taking billions of years to do so. But the fact that we can also see the latent material that we and our star are made of seems to imply that the material travelled faster than the light it emitted. Otherwise, we wouldn't be able to see it, because that light would have passed by our current location long before the material itself arrived here.

    I hope this is sufficiently clear to be understood.

    .
     
  2. jcsd
  3. Oct 27, 2007 #2

    turbo

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    Right now, the redshifts of the most distant objects that we can detect (using a standard Hubble redshift-distance relation as a guide) at z~6.5 would put these objects at bout 800,000 years after the Big Bang. There are some constraints on this model, some of which are highlighted in Michael Strauss' presentation to the Space Telescope Science Institute on Nov 2, 2005. Highly recommended viewing.

    http://www.stsci.edu/institute/itsd...ScienceColloquiaFall2005/MichaelStrauss110205
     
  4. Oct 27, 2007 #3

    Wallace

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    The Universe is very very big, possibly infinite. When we see distant things, we know we are also seeing the light they sent out a long time ago. I think the origin of your confusion is that we don't see the stuff that formed our sun as it looked billions of years ago, what we see is the earlier state of some part of the universe that is a long way away.

    I hope that makes things a little clearer?
     
  5. Oct 27, 2007 #4
    Well I wouldn't necessarily say that what we are looking at 300,000 years after the Big Bang is the stuff of which we are spawned from, in ways that assumption is on the grounds of correctness, but as well it is lacking. Certainly Steve Weinberg's book the First Three Minutes will give you a pretty understanding picture of what took place during the initial stages of our particular universe's creation and consequent formation.

    Though when you speak of matter traveling to this particular place in the cosmos from where the Big Bang took place, you are incorrectly assuming that the Big Bang had a certain state of origination, this, however is incorrect. You may want to instead think of the Big Bang has having infinitely many places of origination, for truly it occurred at every place within the cosmos, for the Big Bang, at that time, was the universe.

    As far as mass coalescing, very firm theories have placed the derivation of material due to helping hands of quantum fluctuations, jitters if you will; these jitters began at microscopic levels, but were eventually frozen in place at macroscopic levels. A prime example of inflation at work, for as quantum fluctuations persisted and grew to enormous size, inflation also acted to scatter this material throughout the universe, more or less in clumps of debris.

    And finally, as far as light that was emitted 300,000 years after the Big Bang, it can presumably be thought of as an impenetrable barrier of which we can see no further. This is due to the fact that the very early universe was an extremely hot place, and it remained that way for some 300,000 years, the result is that a thick wall of plasma completely opaque to light was created. Though above I did say impenetrable with italic styling because it may not be completely impenetrable after all, though that is a different discussion entirely.
     
  6. Oct 28, 2007 #5

    Chronos

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    A neutrino telescope could theoretically peer back to one second after the BB. Constructing such a device is, however, difficult.
     
  7. Oct 28, 2007 #6

    Wallace

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    True, and I think a gravity wave telescope could also see further back than 300,000 years in a statistical sense at least (though not as far as a neutrino telescope I think).
     
  8. Oct 28, 2007 #7
    As far as seeing back to the first few moments after the BB, difficulties surely arise with the whole deal of the opacity and speed of light barrier problems. Though it is certainly possible to feel our most distant universal occupants, a variety of means is thoroughly theoretical, however possible. For instance, detecting the gravity waves emitted from universe horizon, or through capturing the neutrinos released from very ancient atomic processes.

    So, quite possibly, there may be light at the end of this infinitely long tunnel after all.
     
  9. Oct 29, 2007 #8

    Nereid

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    Then there's the faint echo of the universe at a time not much after the neutrino surface of last scattering, imprinted in the (primordial) abundance of the light nuclides.

    Bit of a stretch to call that 'seeing' however ...
     
  10. Oct 30, 2007 #9

    Chronos

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    Neutrinos are so abundant in the early [as well as current] universe such a view would be exquisitely detailed.
     
  11. Nov 3, 2007 #10
    Thanks for the answers, but can I just clarify something?

    Is it right that it would never be possible for us to see (by whatever means) the material in the early universe that would later become us?

    .
     
  12. Nov 3, 2007 #11

    EL

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    That is right! (Since matter is always traveling slower than the speed of light.)
     
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