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Proposition on the big bang

  1. Aug 5, 2014 #1
    Because the speed of light cannot be exceeded, when the big bang happened, the matter that flew out could not have come out at the same time. If it did, the universe would be so crouded in it's first second, it would instantaniously create a large number of black holes swallowing most of the matter.
    Would it be logical to conclude the singularity from our big bang was a black hole in a larger universe, that did not truely explode at once, but rather over a period of time, possibly right at this moment... A white hole?
    I was watching long documentaries, and this concept just came in to my head. What do you people think? Am I thinking about it the wrong way?
  2. jcsd
  3. Aug 5, 2014 #2
    Matter flew out alright, but the thing that exceeded the speed of light was the expansion of space itself. That expansion doesn't (even today) require the actual movement of matter, though it appears to us that that's the case. The expansion of space can cause things embedded in it to appear to move away from each other at more then the speed of light, but that's an illusion. Nothing is actually moving.

    As we speak, things at the edge of our visible universe are disappearing because they're receding from us faster than light can reach us. They aren't being accelerated; space is expanding.
  4. Aug 5, 2014 #3


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    Cosmic natural selection, proposed by Lee Smolin, entertains the idea our universe originated from a black hole in another universe.
  5. Aug 6, 2014 #4


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    Welcome to PF, AstronomyX. As others have mentioned above, the forum rules do prohibit discussion of personal theories or non-mainstream science. However, I think you're more asking a question than putting forward a theory, so I'll let this thread continue.

    With that said, you do appear to misunderstand some basic cosmology. For example, the 'big bang' is often described in popular science as an explosion, however this is not really accurate. The big bang model only says that the universe has expanded and cooled from an originally hot, dense state. In that way, it could appear analogous to an explosion, but once you try and dig deeper the analogy quickly breaks down (i.e. people often ask "Where did the big bang take place?" and the answer is everywhere!).

    You might find it beneficial to take a look at our https://www.physicsforums.com/forumdisplay.php?f=206 [Broken] forum, where we have answered some of the basic questions that are often asked; the "is the universe a black hole" question is addressed https://www.physicsforums.com/showthread.php?t=506992 [Broken]. Additionally, John Baez has a good article on this topic.

    Anyway, have a read of those FAQ and articles, and feel free to post if you have any further questions.

    PS. note that we have a cosmology forum, to which this thread has been moved.
    Last edited by a moderator: May 6, 2017
  6. Aug 6, 2014 #5


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    There are some misconceptions here. It is correct that the homogeneous big bang model does not describe the motion of objects relative to the expanding space, but it is not correct to say things like "the expansion of space exceeded the speed of light" or that the recession velocities of objects are an "illusion" and that they're not "actually moving".

    The expansion of space does not proceed with a speed -- it is really a speed per distance per distance. Consider Hubble's Law: v = Hr, where v is the recession velocity, r the distance to the object, and H the expansion rate. For a fixed rate of expansion, H, we will observe a range of recession velocities in proportion to the distance to the object -- these objects really are receding from us on account of the expansion. Objects at a distance of c/H are receding at light speed -- this is true no matter what the expansion rate is! So it's not correct to talk about space expanding at this or that speed.

    Objects receding from us at light speed are not invisible, i.e. the Hubble scale is not our current event horizon. To see why, think about what happens to a photon emitted towards Earth by a superluminally receding object. You'll find it reaches us just fine if the object is within our event horizon (but, say, still beyond the Hubble radius).

    Today's expansion rate is increasing in time, so that objects are accelerating away from us. Eventually, these objects will traverse the event horizon and then become invisible.
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