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B Is it possible to visualize the big bang?

  1. Oct 30, 2016 #1
    I've never been able to visualize the big bang and my hubris is now leading me to believe it must be impossible. A line in "A Universe from Nothing" talks about how if you look far enough away, since you're looking into the past, you could theoretically see the big bang. I get that; I just can't get a good image in my head. Is it possible to do so? (Please no drawing galaxies on the surface of a balloon.)
  2. jcsd
  3. Oct 30, 2016 #2


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    Science Advisor

    You can in fact see the Big Bang. Here is an image of it taken by the Planck satellite. This is the radiation emitted by the hot gas which filled the universe 380,000 years after the Big Bang, when the universe first became transparent. In the ~13 billion years since, this radiation has been redshifted from the visible down into the microwave region. It is called the Cosmic Microwave Background radiation, and it still fills the universe.

    Attached Files:

  4. Oct 30, 2016 #3
    Yes. the CMB is the first form of light in the Universe, in terms of light as we normally mean it, something actually seeable.
    Although that occurred several years after the initial big bang as such, there would be nothing to be visualised before it,
    (except mathematical models for inflation, and the physics of hot dense plasma )
    Last edited: Oct 30, 2016
  5. Oct 30, 2016 #4


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    My understanding:

    Imagine a very hot, very dense plasma extending to infinity in all directions (assuming an infinite universe of course) at t = 1 second. Now imagine the clock ticking backwards towards zero. This plasma becomes hotter and denser as t approaches 0, yet its dimensions never decrease from infinity. At t = 0 the plasma becomes so dense that our math suddenly breaks down and we lose the ability to make any meaningful predictions (a singularity occurs). As we approached t = 0 the dimensions of the plasma never dropped from infinity, so you have an infinitely dense plasma still with an infinite size despite the fact that it's been contracting the whole way from t = 1 to t = 0.

    If you want to visualize the big bang, in my opinion you should visualize a thick fog (a stand-in for the plasma) that runs in the reverse from what I just said above. IE it expands over time, becoming cooler and less dense at every point in space at the same time. Once t = 380,000 years the fog suddenly lifts as the ions recombine into neutral hydrogen and the universe becomes transparent to EM radiation.
  6. Oct 30, 2016 #5
    Eh.well here is a pop-sci thing which is not completely stupid.
    Other than arbitrary explosion graphics.
  7. Oct 31, 2016 #6
    Many thanks for sharing detail
  8. Nov 5, 2016 #7
    Thanks for your help. The idea of its dimension never decreasing from infinity even as we move backward in time is a strange one but it's very helpful. I still tend to picture the big bang expanding out from a single point even though I know that's not our understanding. Also, when I imagine looking far away to see the big bang, I confuse myself into thinking that it happened "over there". Your fog analogy is a good one, as is your emphasis on density rather than expansion if I understand you correctly. Thanks again!
  9. Nov 5, 2016 #8
    Thank you for your help!
  10. Nov 7, 2016 #9
    It technically happened everywhere.
  11. Nov 13, 2016 #10
    Yes, the arbitrary explosion graphics. The big bang would have looked like nothing as it happened before the formation of photons (?)
  12. Nov 13, 2016 #11
    The early Universe would not have an "appearance" before photon decoupling.
  13. Nov 13, 2016 #12
    Damn such a high school question? Lol's ... just kidding.

    That is a good question because I myself can think of it logically but to be able to visualize is a bit ... maybe beyond my human capability.
    I think the fundamental question to ask is how to visualize something that has more than three dimensions or more since the big bang
    is not something that can be "observed" by an independent observer from afar as many popular programs have been depicting. The big
    bang happens in a, if Einstein is correct, three-dimension space plus time which is space-time continuum which as far as I know nobody
    can honestly say he or she can "visualize" it. One can think of it mathematically but to have a visual image is a little tough since we humans
    are trapped in a three dimensional space. Mathematicians can easily add an extra variable and call it fourth or fifth dimension but I human may
    have a hard time trying to visualize it.

    An easier question to ask although no easier to answer is how to visualize the current universe. How do you visualize the "edge" of the universe?
    Again I can think of it logically and come up with an analogy like the surface of the earth where there is no "edge" but a finite space and so on and so
    on but to say that I can honestly visual what is the "edge" of a four dimensional time-space is a claim I cannot make. I see a lot of visual illustrations
    of the background radiation as a globe or a sphere with the distribution of the temperature but I think that is just an analogy or representation but
    definitely not the actually picture. I mean when you travel to this "edge" that is if I take the WMAP picture literally, what will happen? Obviously there
    is no "edge" in that sense since we are trapped in a 4 dimension space time and we are in it.

    Sorry if I am getting a bit philosophical but may be we can draw a parallel to the particle-wave duality. Maybe there is no duality. The quantum
    world is something beyond our ability to classify and our concepts of "wave" and "particle" is just that - a human concept so we can make sense
    of the world, of reality whatever that may be. Mathematics I guess ultimately is just a representation of reality. Whenever I get stuck, I keep
    thinking like Plato's prisoners in the cave. We can see the effect of reality and when we uncover another layer of "reality", there are even more
    questions to ask almost like an infinite regression.
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