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B Big Bang 2.0

  1. Apr 8, 2016 #1
    Just watched the documentary 'Stephen Hawkings Grand Design: Did God Create The Universe'. S.H. stated that the big bang was similar to subatomic particles that appear, disappear and reappear somewhere else following the laws of quantum mechanics.
    If that were so, wouldn't it also be possible for another big bang to occur in the palm of my hand at any moment?

    My background is not physics by the way, I'm an interested electrical engineer (from Belgium -> explains faulty English).
  2. jcsd
  3. Apr 8, 2016 #2

    The universe may be spawning new universes all the time, as long as their total energy is zero. Of course, we can't really test that idea, so there is no way to know if it's actually happening as far as I know. Once a universe is created, it's no longer our universe, causally disconnected.
  4. Apr 8, 2016 #3
    Ok, cool. So if another universe were to be spawned in the palm of my hand, I wouldn't notice it because the spacetime of the new universe would be unrelated to the spacetime we are part of?
  5. Apr 8, 2016 #4
    It's possible the universe is spawning an infinite number of them in the palm of your hand right now. It's also possible that it's not doing that at all anywhere. Mathematics say it's possible, experiment can't prove it. Physicists are also aware that their equations could be completely wrong too. There are plenty of things in physics that are mathematical possibilities (wormholes for example) that may not have an actual physical existence.
  6. Apr 8, 2016 #5


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    There is nothing that is not a mathematical possibility! You can do what you like in mathematics - you make the rules!
  7. Apr 8, 2016 #6


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    That's a big "if". What Hawking is describing here is not known fact or accepted mainstream theory; it is a speculative hypothesis.

    Also, you should be aware that the term "big bang" here is being used in a different way from the way it is standardly used in cosmology. The standard use of that term refers to the hot, dense, rapidly expanding state of the universe about 13.7 billion years ago, at the end of inflation. But Hawking, in this pop science presentation, is using it to refer to a hypothesized "initial state" of the universe before inflation (or anything else).
  8. Apr 8, 2016 #7
    There are a lot of interesting speculative hypothesis floating around out there. Plenty of mathematical possibilities expressed and MANY existing frameworks to boot. Its an interesting topic but S.H. has a lot of ideas that just cant be proven. The mainstream has a better backbone (experimental data).
  9. Apr 8, 2016 #8
    "The universe may be spawning new universes all the time, as long as their total energy is zero."

    That defies the meaning of the word universe as being universal and all inclusive. But if we are to adopt the concept of something bigger containing multiple "universes" then I see no reason to evoke the conservation of energy, which we have formulated to explain human observations for the last few hundred years in our own little corner of the woods.

    since we have huge discrepancies when we try to apply this to our own observable 'universe' we can not even state from observation that it applies in this context. Assuming that it does is in gross contradiction with observations: a fundamental problem, yet to be resolved by something more than hand-waving and mythological quantities of 'dark matter' and 'dark energy'. aka frig factors.

    Since we have no idea what existed before the big bang and can not even say that such a concept of 'before' has any meaning, it is clearly nonsensical to talk of conservation of anything across such an event.

    Sometimes people seem to have a lack of appreciation that all these natural "laws" are nothing but human mental constructions to explain what we see. They are neither truly natural nor a law independent of the existence of man. If anyone ever breaks the law of conservation of energy they will have to answer to a human court of 'law' , not to nature.

    In fact man will probably be quite grateful and drop the charges, since he will have freed us from our self-imposed serfdom.
  10. Apr 8, 2016 #9


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    Science imposes no 'laws', so to speak, upon nature. All science does is create models that reproduce observations. A good model is one for which no unambiguous exceptions are known to exist and the best models predict things that have defied explanation or even were unknown until we started looking in the right way and in the right places. A good scientist routinely entertains ideas beyond our ability to validate, a great scientist figures out how to do so.
  11. Apr 8, 2016 #10


    Staff: Mentor

    Even if we restrict ourselves to the one observable universe we know about, energy conservation is problematic on a global scale. Sean Carroll does a good job of explaining why in this article:

  12. Apr 8, 2016 #11
    I prefer to stick to the idea that the Universe is an obersvable entity.
  13. Apr 9, 2016 #12
    ... too late to edit that.
    What I meant was that I don't see a lot of point in discussion of possible other universes with which we are causally disconnected.
    1. It's impossible to either validate or falsify any such hypothesis.
    2. Since any such alternate universes are causally disconnected from the one we are in, it makes no difference whether they exist or not.
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