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About the origin of the universe? big bang cause?

  1. Sep 23, 2010 #1
    I'm a physics student but I have not done much astronomy/cosmology. I was sitting here thinking, and something struck me. This thought is only a couple of minutes old so it's not much more than half-arsed musings at this stage. However, I am curious about whether someone who knows what they are talking about thinks idea this sounds plausible or nonsense, or whether this is already a known theory I am just ignorant of.

    It's about the big bang, and what caused it. Was all the matter/energy of the universe supposed to have been concentrated all at once in one point, just sitting there and then exploding? Or, does it sound reasonable to suspect that maybe all the stuff is actually spewing from the singularity of some black hole in some other universe? Maybe the dawn of our time coincided with the collapse of some neutron star or something in this other universe?

    Could this explain the apparent acceleration of the expansion of the universe? What I mean is, if this black hole is growing in this other universe, surely it's sucking in more and more stuff from there and blowing it all out here?
    Do we have any other explanations of why the universe seems to be expanding?
    Is the big bang even considered as still happening today?
    Also, could this explain the way that we seem to have more matter than antimatter - because this black hole just happens to have formed in a region with less of the latter?

    Most importantly, if this all seems possible, is there any conceivable way to test if it is true?

    Apologies if any of this sounds naive, but I'd love to know about this.
  2. jcsd
  3. Sep 23, 2010 #2
    Merely stating the physical state of the Universe at Big Bang is paradoxical because one encounters various infinities such as density infinities although I would find it interesting if Fuzzball's (http://en.wikipedia.org/wiki/Fuzzballs) in Superstring Theory could help describe a Universe when it is in a state of planck density. Your idea about Black Holes appears to be similar to Lee Smolin's idea but I'm not sure. We already know why the Universe is expanding, it is because of the existence of Dark Energy and inflation was likely caused by the emergence of some inflation field and particle, the Inflaton.
  4. Sep 23, 2010 #3
    oh, cool, I wasn't aware of this.
  5. Sep 24, 2010 #4
    1. It was not an explosion. It is a common misconception. Please read FAQ.
    2. As there was no time before the Big bang (or at least the notion of Time cant be used in a form we got used to), the cause (event preceding smth in time) becomes ill-defined concept.
  6. Sep 24, 2010 #5
    Does this matter though? I mean, if a black hole suddenly formed and the first stuff started falling through, couldn't that be taken as the start of time? You wouldn't need to think of times earlier than that?
  7. Sep 24, 2010 #6
    No of course.
    What you are suggesting is 'beginning of time by ignorance' – like as events before were irrelevant you can declare some moment of time as ‘beginning of time’. Big bang has completely different nature – you can’t continue time, even theoretically, to the moment before the Big Bang (I don’t want to talk at the moment about superstring theories)

    Your very sentence states at least 2 events before your 'beginning of time'
    Formation of the Black hole
    Stuff (created when?) starting to fall inside
    How can you can some moment 'the beginning of time' if there are events before it?
  8. Sep 24, 2010 #7
    Sorry, what I meant was, this black hole forms in this other universe, which has plenty of previous time.

    Or, let's say somewhere in our universe, a black hole has just formed right now. On the other side of that black hole, that new universe's time starts from zero?
    Does this make any more sense?
  9. Sep 24, 2010 #8
    Black holes are super-dense objects that form a "singularity". Although the notion of a singularity is rather mundane because infinities are unreasonable and aren't very intuitive. I'm not sure what makes you posit that Universes form from Black Holes I'm quite certain the energy wouldn't be sustainable and Black Holes would have very distinct properties if this were true.
  10. Sep 24, 2010 #9
    While Schwarzschild solution is time symmetric (white hole and black hole + 'another side'), that solution is not realistic, because it is possible only with unrealistic boundary conditions - flat eternal universe. Realistic black holes dont have 'white hole' part and 'the other side' (negative radius space).
  11. Sep 24, 2010 #10
    well that's kicked my little theory into touch, lol.
  12. Sep 27, 2010 #11
    No one really knows. There are several ideas for what happened "before" the big bang, but right now it's mostly speculation. It's interesting speculation, but it's speculation at this point.

    It turns out that a universe that obeys anything like general relativity just can't be static. So either the universe is expanding or it's contracting, and if it were contracting then the blue-shifted light from distant galaxies would fry us all.
  13. Sep 27, 2010 #12
    On the other hand you can wave your hands and say that something weird happens in quantum gravity and that a collapsing black hole will create an inflationary bounce. Leo Smolin's cosmological natural selection is based on that idea.

    It turns out that the hard part is not coming up with weird ideas. It's making weird ideas testable. One thing that we'll likely be able to do in the next decade is to have enough information about the cosmic microwave background to rule out some ideas.
  14. Sep 27, 2010 #13
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