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Why Stephen Hawking says universe can create itself from nothing?

  1. Feb 24, 2013 #1
    Hello all .
    I can not explain good but hope you will understand my purpose .

    I read in University Oregon's website that universe came from a pure energy in vacuum
    If we want to say exactly , we can say universe came from Potential energy in vacuum .

    We know in physics there are some conversation laws such as conversation of energy and conversation of angular and linear momentum and son on .

    And we know momentum is a quantity that can carry by objects and particles like electrons and photons and in generally any elementary particles .

    And we know in early universe there aren't any particles or objects just existed pure energy .

    And we know energy isn't physical object or particle .

    My first question is :

    1 -Was there in early universe any momentum ? conversation of momentum says it should be existed ( like energy ) but this momentum carry by what (or which ) particles or objects ?


    My second question is :
    2 - energy is thing or nothing ? why Stephen Hawking says universe came from nothing ? if we consider universe came from pure energy .


    My third question is :
    3- why we can not say universe came from pure momentum ? why we must say universe came from pure energy ?


    I really confused .

    Thanks for your help .
     
    Last edited: Feb 24, 2013
  2. jcsd
  3. Feb 24, 2013 #2
    Yes, momentum. But how "early" do you want to go?
    :rolleyes:
    Energy is a mere concept. A useful idea if the only brain you have is a poor human one :rolleyes:

    We cannot say "came from" because if so that would be "before the beginning"
     
  4. Feb 24, 2013 #3

    MathematicalPhysicist

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    You should really not listen to this nonsense.

    I don't care how intelligent Stephen is, nothing can be created from nothing, so does he posit that we are actually really just nothing?
     
  5. Feb 24, 2013 #4
    The universe from nothing model isnt quite as crazy as you might think. A lot of top level cosmologists feel that it is a strong possibility.
    Here is a quick guideline on process.
    Key point in order for this model to work is that energy density must balance with zero energy. Gravity being considered as negative energy.
    Rapid expansion occurs this creates a false vacuum. This false vaccuum. To maintain energy conservation energy is borrowed. I cant recall what the model states its borrowed from but if I recall its borrowed from gravity.
    With that energy quantum tunneling occurs from virtual particles. Some of the virtual particles tunnel to the true vacuum. Leaving real particles.

    It should be noted that virtual particles are created in a large variety of sources. Cosmological horizons. =Unruh radiation. Blackholes is Hawking radiation. Schwinger particle production is electromagnetic disturbences. Parker radiation is due to expansion.
    All of the above are various blackbody radiation.

    There are countless other particle production methods.
    What they all boil down to is a vacuum is never empty.
    False vacuum being the lowest energy state has quantum fluctuations described by Heisenburg uncertainty principle. Those fluctuations in turn create virtual particles. Those virtual particles in the right circumstances become real particles.
    Throughout out all this for this model the energy density must stay equal to zero with gravity and vacuum energy as part of the balancers.
    However even if the energy density isnt zero the various particle production methods describe above are all still valid.
    Sounds crazy however their is tons of research and models that support this ultimate free lunch.
     
    Last edited: Feb 24, 2013
  6. Feb 24, 2013 #5
    Here is a link to a description of false vacuum.
    http://ned.ipac.caltech.edu/level5/Guth/Guth3.html

    if your interested in some of the other particle producers I can post some decent articles on them
     
  7. Feb 25, 2013 #6

    Chalnoth

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    Why not?
     
  8. Feb 25, 2013 #7

    MathematicalPhysicist

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    Cause to create something from nothing you need to do something illogical, magical, mystical.

    And that's the break of rationality, it's possible, but then I might as well also believe in witches and fairies.
     
  9. Feb 25, 2013 #8
    I'm afraid it has been always like this, when something large is about to reveal itself the majority can't believe their eyes.
    Imagine the first light bulb or the fact that most of the scientists at the time believed that nothing heavier than air could fly.
    Ok I understand this is a much bigger issue here that were facing not comparable to some jumbo jets or light bulbs but if it exists and if we exist then there was a way it started we may not understand or have access to that way but that doesn't make the way it went less real or possible.
     
  10. Feb 25, 2013 #9

    Chalnoth

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    Prove it.
     
  11. Feb 25, 2013 #10
    First, leaving aside the creation activity, you can have a positive and a negative which compensate to zero. Both exist. It depends then what you mean by something and nothing.

    Secondly, creation is going on all the time in so called empty space, with matter and antimatter particles anihilating each other.

    So putting the two together, we can easily have creation from nothing.

    "You" don't have to do anything, if creation is an automatic and therefore inevitable process.

    .
     
  12. Feb 25, 2013 #11

    phinds

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    Lawrence Krause has a whole book about this, "A Universe from Nothing", in which he supports this theory.
     
  13. Feb 25, 2013 #12
    The reaction your having is a coomon problem. However its one that stems from lack of knowledge in current cosmology. Not everything in science is easily understood by common sense. quantum entanglement is another that defies common sense.

    With that in mind Can you show another model that expains how everything can develop? In cyclic models how did the first universe start?
    Same applies to commoving models.
    The one advantage this model presents is its lack of needing an outside source.
    However the OP did not ask for personal opinions.
    His post wanted an understanding of Hawkings statement. That has been provided personal opinions aside
     
  14. Feb 25, 2013 #13
    So far in all our efforts 'nothing' always amount to something. It only make sense if you put constraints on nothing(vacuum/false vacuum/empty space)".
     
  15. Feb 25, 2013 #14

    rbj

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    where should the burden of proof be? that nothing comes from nothing? or that something comes from nothing? why should the burden of proof be on the former rather than the latter?
     
  16. Feb 25, 2013 #15

    Chalnoth

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    He made a positive statement: it is impossible to create something from nothing. I asked him to back that statement up with more than ridicule.

    The default should always be, "We don't know." If somebody had stated, "The universe was created from nothing in this specific way," then that would be a statement requiring evidential support. MathematicalPhysicist made a much, much stronger statement: that there is no possible way that something can come from nothing. That statement requires a mathematical proof as support.
     
  17. Feb 25, 2013 #16

    rbj

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    for those of us that don't have the book and don't expect to order it, might you summarize the best argument for this notion? i would be quite interested.

    i remember listening to Michael Schermer about it, and he said "maybe something is a more stable state than nothing."

    it sounded like it was kinda an appeal to the notion that the big bang was a humongous quantum fluctuation. instead of an electron or some other sub-atomic particle just appearing or disappearing somewhere due to the nature of QM, a whole primordial universe just pops into existence 13.7 billion years ago.
     
  18. Feb 25, 2013 #17

    rbj

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    okay, so i'll turn it around to this positive statement: "The Universe we observe created itself from nothing approximately 13.7 billion years ago."

    why should the burden of proof be applied to the contrary rather to this positive statement?

    boy, am i glad to read you say that.


    this requires more than "mathematical proof". again (from the other thread), the mathematical relationships we call "physical law" describe the interaction of "stuff". the math is not the "stuff". and "stuff" is not "nothing".
     
  19. Feb 25, 2013 #18
    my third question is :
    3- why we can not say universe came from pure momentum ? why we must say universe came from pure energy ?

    I'm no expert on quantum theory, but I have not seen momentum ascribed to vacuum energy.

    Vacuum energy:

    http://en.wikipedia.org/wiki/Vacuum_energy

    Another way to think about this is to consider potential energy....energy without momentum AFAIK.

    The zero point energy, vacuum energy, false vacuum, vacuum expectation value, call it what you will, all are related to the potential energy of the Hamiltonian formalism and to the Heisenberg uncertainty principle...that is, quantum jitters or uncertainty.....
     
  20. Feb 25, 2013 #19

    Chalnoth

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    But when you say something is impossible, that requires a mathematical proof. That proof may be based upon specific assumptions that are grounded in evidence, but it requires proof nonetheless.

    Anyway, I'll just put forward that it cannot be done, because the very concept of 'nothing' isn't a well-defined concept in the first place. Somebody could put forward a model that claims to be a start of the universe from nothing, and the other person can simply respond, "But that's not what I meant by nothing!" So in the end, arguing about whether or not the universe could have started from nothing is both a ridiculous and unhelpful line of argument.

    Things get much more interesting when we start to consider actual models for generating our observable universe. Then there's actually a sensible conversation to be had, where things aren't necessarily bound to devolve into a useless argument over the definition of 'nothing'.

    For example, it seems quite likely, given current evidence, that our observable universe started with a period of inflation. During inflation, our entire observable universe (and much that lies beyond it) came from a small inflating patch that need not have been any larger than a proton.

    This suggests an interesting possibility: what if our universe began with a microscopic quantum vacuum fluctuation? That is, previous to the start of our universe, there might have been some other universe which was mostly empty (as ours will be in the far future). Such a vacuum isn't completely inert: it tends to bubble and froth with quantum mechanical particles. Perhaps one of those bubbles was just right to get inflation started, creating a new universe (ours).

    From outside this bubble, it would look like a microscopic black hole had popped into existence, then quickly decayed. From the inside, we have a whole universe. The physical process can be sort of visualized by imagining that the parent universe is sort of a membrane that tends to wiggle all the time. At some point one of these wiggles got exceptionally large and sharp, and pinched off a little bubble. That bubble, now disconnected from the parent universe, grew on its own to become a large universe in its own right.

    This, of course, is a picture of how our universe might have started from some other. It can be said to have started from nothing in the sense that it started from a previous vacuum state, even if some might argue that that wasn't really nothing. But whichever way you slice it, it is a way to generate new regions of space-time by a dumb, purposeless physical process. And that I find interesting.

    Now, it is conceivable that somebody might come up with a way to describe a universe's beginning without there being anything before (no space-time, no matter, nothing), but that comes with a significant problem: how do you describe 'nothing' mathematically? This doesn't mean it's impossible, but it does mean that we can't really start to examine the possibility without a coherent description of what 'nothing' actually means.
     
  21. Feb 25, 2013 #20

    MathematicalPhysicist

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    That's really simple.

    If you create something from nothing then that nothing becomes something, cause if it were nothing then how did we got something?

    As I said it's not logical, and we might as well start believe in witches and fairies if that's what we come to believe.
     
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