14 ms·

Mathematics of Eternity Prove The Universe Must Have Had A Beginning

97 points by kenhty 14y ago

Jun8 14y ago
You can read John Rennie's excellent answer to this question (http://physics.stackexchange.com/questions/24018/how-can-something-happen-when-time-does-not-exist http://physics.stackexchange.com/questions/24018/how-can-som...) that always comes up during discussions on time.
- joering2 14y ago
  it was a good read, I +1 you. what literally gives me a headache if I think about it for longer than 45 seconds is this question how come something could exist before anything existed. It had to exist, otherwise what existed after that wouldn't be created. But it was, and our universe and we are a prove of it. It feels like an almost perfect crime that we are a result of, if you can follow my thought here. I dont care how many billion of years in past I have to dig into. I dont care how many billions of lightyears I need to travel. At the end, at some point, there must be an end. Whats after it? Just think of it, for a moment. It exists right now in this second. Sure you wont see it in your lifetime, or experience it, but taken out time and distance from this equation, you would be there and experience it. Awesome stuff...
iwwr 14y ago
"A universe from nothing" by Lawrence Krauss presents the possibility of a universe without a beginning, even one containing "nothing", yet still be compatible with present cosmology. My general impression is that by "nothing" he means "averaged out, zero energy" and with a set of laws (quantum mechanics) that can generate fluctuations. Out of these fluctuations you can have particles of various energy arising (which normally live short lives and decay back into nothingness). But given enough time you could have a large enough fluctuation that generates a big bang, followed by very long inflation and cooling. Equally so, you could have a fluctuation that winks all the known universe into a void, suddenly and without warning.
- TeMPOraL 14y ago
  I heard once on Oxford SciBar (I think that one - http://www.oxfordscibar.com/september-2011.html http://www.oxfordscibar.com/september-2011.html) a scientist who said that universe could really come from nothing, if all energy in it summed up to 0. EDIT BTW. Oxford SciBar is an awesome event, so if one lives or happens to stay in Oxford for some time, it's worth checking out.
- craftsman 14y ago
  I've always thought these "universe from nothing" statements are more than a bit deceptive if they mean "averaged out, zero energy". If there is some background with a set of laws that produce fluctuations, it's hard for me to see how that is nothing. But I'm no physicist. :)
  - cristianpascu 14y ago
    I'm a Physicist, and it's not 'nothing'. :) Lawrence is engaged in a metaphysics program. He wants to show that atheism is intellectually justified as to the origin of the Universe, as they feel it is with the darwinian theory of origin of species.
    - derleth 14y ago
      > atheism is intellectually justified It is, and will be, until the people who believe in the supernatural provide solid evidence for their specific claims.
      - cheald 14y ago
        It's worth noting that the meaning of the very word "supernatural" precludes the possibility of solid evidence.
        cristianpascu 14y ago
        I agree. People often mistake the two domains of reality. Just because the physical reality is given and closer to us, we can't rule out other forms of existence. And say that, somehow, a percentage of humans had some sort of experience of the supernatural. Then they pass on that information. Some believe them, some don't. It's a matter of confidence. Some of the ones that just believed in the first place, eventually get to also have those spiritual experiences. One could also make conjectures about the nature of those spiritual experiences: that they were illusions, hallucinations, or real experiences. But it can not be objectively verified. And there will always be a percentage of people what will not believe. Taking the exigence of objective, material verification of experiments in Physics to a field of subjective, psychological/spiritual experiences, seems to me to be a mistake.
jbert 14y ago
I've found one useful way to think about the question "what was before the Big Bang" is to ponder "what is North of the North pole"? Don't stretch the analogy too far - I'm not suggesting that spacetime is topologically shaped like that - but to me it's a useful example of a co-ordinate system which seems locally euclidean going whacky at/near the boundaries. Roughly, "But there has to be something before the big bang, you just go back a bit further in the same direction!" == "But there has to be something North of the pole - you just go a bit further in the same direction!"
- ccozan 14y ago
  The problem is that you an use words like "go" and "direction" in a situation where they make sense. In the incipient phase of the Universe the space-time did not exist as we can perceive it with our brains, themselves based on physical and chemical properties of the mature Universe - so would be impossible to "imagine" that there is no "north" because there is no direction available. Kant deducted that our conscience and brains are born with the sense of space-time and we cannot override this. The only way in which we can access this ideas is only through highend mathematics and AIs that just need to do a job, but not to explain to our limited brains how.
  - dredmorbius 14y ago
    Kant may have deducted that, but he's talking about a neurobiological phenomenon born from evolutionary pressures in a very limited environment. Michelson–Morley mesured, and Einstein explained, how speed of light, not time, is constant through the Universe. To the point of questioning simultaneity. If we've already got non-constant time, then the concept of a time origin prior to which there is no sensible physical description is at least plausible, if not something I can, spacial geometric puns pardoned, wrap my brain around in the same sense that there's a limit to "northness" on a spheroid.
  - jbert 14y ago
    Yes, the idea of the analogy is that these concepts "make sense" near our current space-time location, but break down near the edges of our universe. Our brains think that "North" and "earlier" are directions which can be extended infinitely, but they are wrong.
OzzyB 14y ago
This is my theory. After watching Steven Hawking's series on The Universe, he talked about Black Holes and how they keep growing and growing; sucking in more mass and getting denser and denser, whilst at the same time amasing more gravity. i.e. the more mass something has, the more gravity it exerts, the more mass it attracts -- a viscious cirle. So my theory, don't laugh, is that the universe if cyclical. After a Black Hole has consumed everything, including other Black Holes etc. it explodes and all that mass gets released creating the universe as we know it. And so on and so on over a gazillion years. Is that absurd? Edit: Many thanks for the informative replies...
- theootz 14y ago
  http://en.wikipedia.org/wiki/Cyclic_model http://en.wikipedia.org/wiki/Cyclic_model edit and http://en.wikipedia.org/wiki/Loop_quantum_cosmology http://en.wikipedia.org/wiki/Loop_quantum_cosmology
- jbattle 14y ago
  Two things to consider: 1) The volume of space a black hole influences doesn't increase without bound. If our sun collapsed suddenly into a black hole, it would have the same exact pull on the earth (i.e. we wouldn't suddenly be pulled into the black hole) 2) It is hypothesized that black holes do evaporate slowly (see Hawking radiation http://en.wikipedia.org/wiki/Hawking_radiation http://en.wikipedia.org/wiki/Hawking_radiation)
- SatvikBeri 14y ago
  The rough idea-that the universe is cyclical, not necessarily the black holes-is in fact one of the models explored in the paper.
- drcube 14y ago
  The universe contains more than matter. Did every last photon ever emitted end up in a black hole too? Or is the universe losing energy with every cycle? This is besides the empirical evidence against a cyclical universe. Cosmological expansion is accelerating, rather than slowing down, as you would expect if gravity were to slow everything down enough to eventually contract.
ThomPete 14y ago
The question is not whether the universe had a beginning but rather how many times.
- twiceaday 14y ago
  Big bang is not certain. Yes the cosmological background radiation is evenly distributed, and yes Hubble law makes accurate predictions, but these aren't proofs. I watched a documentary recently on this subject and most theoretical physicists surveyed did not believe in the big bang.
  - drgath 14y ago
    I recently attended a lecture given by an astronomy professor/cosmologist who concurred that yes, the big bang is on its way out as the accepted truth. Like a swirling drain, we're getting closer, and there are aspects of the theory that are (likely) true, but it is far from bullet-proof and will likely go the way of the dozens of other origin theories that were disproven before it.
  - dekz 14y ago
    I'd be interested in the documentary if you could provide a title!
    - twiceaday 14y ago
      It's called "Horizon: What Happened Before the Big Bang?".
  - Drbble 14y ago
    Survey isnt really a great way to form a scientific opinion. The presence of disagreement is relevant. But majority vote is not.
  - ThomPete 14y ago
    That is kind of my point :)
- Flow 14y ago
andrewcooke 14y ago
this builds on an earlier theorem, which i haven't looked at (and probably wouldn't understand anyway) which apparently makes rigorous the intuitively attractive idea that if you trace back in time something that is getting bigger then at some point you reach zero. the reason oscillating universes are caught out by this is that (apparently - this is all just my impression on a quick skim, having never understood things much and leaving astronomy - not even astrophysics - decades ago) even though they oscillate, they need to get systematically bigger to work around some problems with entropy. another model they considered is a universe that "just sits there" like a seed, forever, until (randomly) deciding to grow. and that has problems with quantum mechanics (which you can imagine - how can something be stable for an infinite amount of time?). one problem is that it's a paper that really only attacks current models. they don't prove that no other model could be thought up. you could also argue another weakness of the paper is a reliance on our notions of basic physics (quantum and statistical mechanics) holding true even in the distant past. but then, what else can you do?
ck2 14y ago
I'm a fan of the white-hole theory (big bang is opposite side of a super massive black hole in another universe)
- VMG 14y ago
  Theory or "idea"?
  - SquareWheel 14y ago
    Theory.
  - ck2 14y ago
    http://en.wikipedia.org/wiki/White_hole http://en.wikipedia.org/wiki/White_hole White holes appear as part of a solution to the Einstein field equations known as the maximally extended version of the Schwarzschild metric We may be one of a processes of cosmological natural selection: http://en.wikipedia.org/wiki/Fecund_universes#Fecund_universes http://en.wikipedia.org/wiki/Fecund_universes#Fecund_univers...
    - kstenerud 14y ago
      Alternatively, the Red Dwarf explanation: http://www.youtube.com/watch?v=TxWN8AhNER0 http://www.youtube.com/watch?v=TxWN8AhNER0
    - VMG 14y ago
      Thanks, guess my tone was too sarcastic...
lelf 14y ago
Paper: http://arxiv.org/pdf/1204.4658v1.pdf http://arxiv.org/pdf/1204.4658v1.pdf
nooneelse 14y ago
Creation of something from nothing seems rather functionally equivalent to destruction of a something into nothing with time reversed. Is there any known process or way to take something and destroy it utterly into nothing? If not, then what would make such an utter destruction possible given a reversed direction of time? Except as an abstraction, it seems to me that no one has any real experience of nothing. As an empiricist, that gives me quite a bit of pause when anyone starts making claims about nothing (myself being no exception).

97 points by kenhty 14y ago

Jun8 14y ago

You can read John Rennie's excellent answer to this question (http://physics.stackexchange.com/questions/24018/how-can-something-happen-when-time-does-not-exist http://physics.stackexchange.com/questions/24018/how-can-som...) that always comes up during discussions on time.

joering2 14y ago
it was a good read, I +1 you. what literally gives me a headache if I think about it for longer than 45 seconds is this question how come something could exist before anything existed. It had to exist, otherwise what existed after that wouldn't be created. But it was, and our universe and we are a prove of it. It feels like an almost perfect crime that we are a result of, if you can follow my thought here. I dont care how many billion of years in past I have to dig into. I dont care how many billions of lightyears I need to travel. At the end, at some point, there must be an end. Whats after it? Just think of it, for a moment. It exists right now in this second. Sure you wont see it in your lifetime, or experience it, but taken out time and distance from this equation, you would be there and experience it. Awesome stuff...

iwwr 14y ago

"A universe from nothing" by Lawrence Krauss presents the possibility of a universe without a beginning, even one containing "nothing", yet still be compatible with present cosmology. My general impression is that by "nothing" he means "averaged out, zero energy" and with a set of laws (quantum mechanics) that can generate fluctuations. Out of these fluctuations you can have particles of various energy arising (which normally live short lives and decay back into nothingness). But given enough time you could have a large enough fluctuation that generates a big bang, followed by very long inflation and cooling. Equally so, you could have a fluctuation that winks all the known universe into a void, suddenly and without warning.

TeMPOraL 14y ago
I heard once on Oxford SciBar (I think that one - http://www.oxfordscibar.com/september-2011.html http://www.oxfordscibar.com/september-2011.html) a scientist who said that universe could really come from nothing, if all energy in it summed up to 0. EDIT BTW. Oxford SciBar is an awesome event, so if one lives or happens to stay in Oxford for some time, it's worth checking out.
craftsman 14y ago
I've always thought these "universe from nothing" statements are more than a bit deceptive if they mean "averaged out, zero energy". If there is some background with a set of laws that produce fluctuations, it's hard for me to see how that is nothing. But I'm no physicist. :)
- cristianpascu 14y ago
  I'm a Physicist, and it's not 'nothing'. :) Lawrence is engaged in a metaphysics program. He wants to show that atheism is intellectually justified as to the origin of the Universe, as they feel it is with the darwinian theory of origin of species.
  - derleth 14y ago
    > atheism is intellectually justified It is, and will be, until the people who believe in the supernatural provide solid evidence for their specific claims.
    - cheald 14y ago
      It's worth noting that the meaning of the very word "supernatural" precludes the possibility of solid evidence.
      - cristianpascu 14y ago
        I agree. People often mistake the two domains of reality. Just because the physical reality is given and closer to us, we can't rule out other forms of existence. And say that, somehow, a percentage of humans had some sort of experience of the supernatural. Then they pass on that information. Some believe them, some don't. It's a matter of confidence. Some of the ones that just believed in the first place, eventually get to also have those spiritual experiences. One could also make conjectures about the nature of those spiritual experiences: that they were illusions, hallucinations, or real experiences. But it can not be objectively verified. And there will always be a percentage of people what will not believe. Taking the exigence of objective, material verification of experiments in Physics to a field of subjective, psychological/spiritual experiences, seems to me to be a mistake.

jbert 14y ago

I've found one useful way to think about the question "what was before the Big Bang" is to ponder "what is North of the North pole"? Don't stretch the analogy too far - I'm not suggesting that spacetime is topologically shaped like that - but to me it's a useful example of a co-ordinate system which seems locally euclidean going whacky at/near the boundaries. Roughly, "But there has to be something before the big bang, you just go back a bit further in the same direction!" == "But there has to be something North of the pole - you just go a bit further in the same direction!"

ccozan 14y ago
The problem is that you an use words like "go" and "direction" in a situation where they make sense. In the incipient phase of the Universe the space-time did not exist as we can perceive it with our brains, themselves based on physical and chemical properties of the mature Universe - so would be impossible to "imagine" that there is no "north" because there is no direction available. Kant deducted that our conscience and brains are born with the sense of space-time and we cannot override this. The only way in which we can access this ideas is only through highend mathematics and AIs that just need to do a job, but not to explain to our limited brains how.
- dredmorbius 14y ago
  Kant may have deducted that, but he's talking about a neurobiological phenomenon born from evolutionary pressures in a very limited environment. Michelson–Morley mesured, and Einstein explained, how speed of light, not time, is constant through the Universe. To the point of questioning simultaneity. If we've already got non-constant time, then the concept of a time origin prior to which there is no sensible physical description is at least plausible, if not something I can, spacial geometric puns pardoned, wrap my brain around in the same sense that there's a limit to "northness" on a spheroid.
- jbert 14y ago
  Yes, the idea of the analogy is that these concepts "make sense" near our current space-time location, but break down near the edges of our universe. Our brains think that "North" and "earlier" are directions which can be extended infinitely, but they are wrong.

OzzyB 14y ago

This is my theory. After watching Steven Hawking's series on The Universe, he talked about Black Holes and how they keep growing and growing; sucking in more mass and getting denser and denser, whilst at the same time amasing more gravity. i.e. the more mass something has, the more gravity it exerts, the more mass it attracts -- a viscious cirle. So my theory, don't laugh, is that the universe if cyclical. After a Black Hole has consumed everything, including other Black Holes etc. it explodes and all that mass gets released creating the universe as we know it. And so on and so on over a gazillion years. Is that absurd? Edit: Many thanks for the informative replies...

theootz 14y ago
http://en.wikipedia.org/wiki/Cyclic_model http://en.wikipedia.org/wiki/Cyclic_model edit and http://en.wikipedia.org/wiki/Loop_quantum_cosmology http://en.wikipedia.org/wiki/Loop_quantum_cosmology
jbattle 14y ago
Two things to consider: 1) The volume of space a black hole influences doesn't increase without bound. If our sun collapsed suddenly into a black hole, it would have the same exact pull on the earth (i.e. we wouldn't suddenly be pulled into the black hole) 2) It is hypothesized that black holes do evaporate slowly (see Hawking radiation http://en.wikipedia.org/wiki/Hawking_radiation http://en.wikipedia.org/wiki/Hawking_radiation)
SatvikBeri 14y ago
The rough idea-that the universe is cyclical, not necessarily the black holes-is in fact one of the models explored in the paper.
drcube 14y ago
The universe contains more than matter. Did every last photon ever emitted end up in a black hole too? Or is the universe losing energy with every cycle? This is besides the empirical evidence against a cyclical universe. Cosmological expansion is accelerating, rather than slowing down, as you would expect if gravity were to slow everything down enough to eventually contract.

ThomPete 14y ago

The question is not whether the universe had a beginning but rather how many times.

twiceaday 14y ago
Big bang is not certain. Yes the cosmological background radiation is evenly distributed, and yes Hubble law makes accurate predictions, but these aren't proofs. I watched a documentary recently on this subject and most theoretical physicists surveyed did not believe in the big bang.
- drgath 14y ago
  I recently attended a lecture given by an astronomy professor/cosmologist who concurred that yes, the big bang is on its way out as the accepted truth. Like a swirling drain, we're getting closer, and there are aspects of the theory that are (likely) true, but it is far from bullet-proof and will likely go the way of the dozens of other origin theories that were disproven before it.
- dekz 14y ago
  I'd be interested in the documentary if you could provide a title!
  - twiceaday 14y ago
    It's called "Horizon: What Happened Before the Big Bang?".
- Drbble 14y ago
  Survey isnt really a great way to form a scientific opinion. The presence of disagreement is relevant. But majority vote is not.
- ThomPete 14y ago
  That is kind of my point :)
Flow 14y ago

andrewcooke 14y ago

this builds on an earlier theorem, which i haven't looked at (and probably wouldn't understand anyway) which apparently makes rigorous the intuitively attractive idea that if you trace back in time something that is getting bigger then at some point you reach zero. the reason oscillating universes are caught out by this is that (apparently - this is all just my impression on a quick skim, having never understood things much and leaving astronomy - not even astrophysics - decades ago) even though they oscillate, they need to get systematically bigger to work around some problems with entropy. another model they considered is a universe that "just sits there" like a seed, forever, until (randomly) deciding to grow. and that has problems with quantum mechanics (which you can imagine - how can something be stable for an infinite amount of time?). one problem is that it's a paper that really only attacks current models. they don't prove that no other model could be thought up. you could also argue another weakness of the paper is a reliance on our notions of basic physics (quantum and statistical mechanics) holding true even in the distant past. but then, what else can you do?

ck2 14y ago

I'm a fan of the white-hole theory (big bang is opposite side of a super massive black hole in another universe)

VMG 14y ago
Theory or "idea"?
- SquareWheel 14y ago
  Theory.
- ck2 14y ago
  http://en.wikipedia.org/wiki/White_hole http://en.wikipedia.org/wiki/White_hole White holes appear as part of a solution to the Einstein field equations known as the maximally extended version of the Schwarzschild metric We may be one of a processes of cosmological natural selection: http://en.wikipedia.org/wiki/Fecund_universes#Fecund_universes http://en.wikipedia.org/wiki/Fecund_universes#Fecund_univers...
  - kstenerud 14y ago
    Alternatively, the Red Dwarf explanation: http://www.youtube.com/watch?v=TxWN8AhNER0 http://www.youtube.com/watch?v=TxWN8AhNER0
  - VMG 14y ago
    Thanks, guess my tone was too sarcastic...

lelf 14y ago

Paper: http://arxiv.org/pdf/1204.4658v1.pdf http://arxiv.org/pdf/1204.4658v1.pdf

nooneelse 14y ago

Creation of something from nothing seems rather functionally equivalent to destruction of a something into nothing with time reversed. Is there any known process or way to take something and destroy it utterly into nothing? If not, then what would make such an utter destruction possible given a reversed direction of time? Except as an abstraction, it seems to me that no one has any real experience of nothing. As an empiricist, that gives me quite a bit of pause when anyone starts making claims about nothing (myself being no exception).