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Thread: Relating to the Big Bang, is time finite or infinite?

  1. #1 Relating to the Big Bang, is time finite or infinite? 
    ...matter and pixie dust
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    This is a point that I've always been a bit confused on, no matter how much I've read about the Big Bang Theory. I'm hopeful someone can provide an answer for me. It's often been discussed that time didn't 'exist' before the Big Bang. What does that mean, exactly? That time was only ''established'' after the BB happened? If so, do we believe time to be finite? Or can it be infinite? Is it because we don't have a single set of consequences (that we know of) that led up to the BB, that we can't definitely say if time existed or not? It's just a confusing point to me. The BB is our universal starting point if you will, for time...but there are some 'theories' floating around, that give some speculative perspective on time before the BB, (ie: membrane theory) but what to believe? For the record, I accept the BB theory, and this thread isn't to dispute that. (just wanted to make that part clear) Thanks in advance, for your input.


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  3. #2  
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    The big bang is the starting point for time as we know it. Any answer to the questions you raised would be purely speculative.


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    Do you know what God did before he created time and space? He created hell for people who asks such questions No, really there isnīt any theory that would answer these questions not even speculative ones like string theory.
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  5. #4  
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    So, then all theories would be speculative...okay. Thank you mathman and Gere..it's just odd to me how 'something' could start from 'nothing.'
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  6. #5  
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    What does that mean, exactly?
    I often use an analogy here which I find rather useful - think of the Big Bang as a "pole" in space-time. Imagine you were to start walking north from your house; you walk and walk, and eventually you reach the North Pole. Then what ? Can you walk further north from the North Pole ? Of course not, because everywhere you face will now be "south". Same in space-time; you go back and back until you reach the Big Bang. Then what ? Any "direction" you face at that event will always be "the future"; you cannot go backwards from the Big Bang anymore than you can go north from the north pole. The concept simply does not make sense.

    Or can it be infinite?
    Space-time can be infinite, that is indeed a distinct possibility.
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  7. #6  
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    At the beginning, matter would have been so tightly compact that it would be a singularity. From the perspective of any outside observer, time inside a singularity appears to stand still. From the perspective of an inside observer it proceeds normally.

    Now, in a 3 Dimensional sense, we never left the singularity. It just stopped being a singularity. The universe expanded until the matter was not so concentrated anymore. If we take that perspective, then the Big Bang was a finite length of time ago.

    However, in a 4 dimensional sense, we've moved very far away from the singularity. When we look back in time, we are observers outside of the singularity looking in toward a singularity.

    It's kind of a clumbsy argument, but depending on what perspective we take, we might view the Big Bang event as being infinitely long ago. (There is another argument for how we might view the universe as being infinitely large in a 3D spatial sense also, due to the Hubble Sphere being unreachable at the Speed of Light.)
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    It's more likely that there wasn't "nothing" before the big bang, it's just we have no proof of existence before hand. Time is relative, and therefore our time line started when the big bang did. There has been a finite amount of time since then because we can date it back to 13.7 billion years, but there very well could be an infinite amount of time ahead of us. If we had something to base time from that was before the big bang we'd have a greater perspective, but because we don't it seems that it's the first thing to happen in the Universe - which is highly improbable, though impossible to prove. Everything about time and the beginnings of the Universe is purely speculative, but it's likely that the big bang wasn't the first of it's kind. Our Universe doesn't seem to be very disorderly and whatever exists once usually recurs.
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  9. #8  
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    I appreciate the replies here...thank you for taking the time! the definition of nothing as being something science can't quantify, or 'explain,'' is the general acceptable scientific explanation, ok...but, that doesn't mean there was literally nothing pre-Big Bang. It just means...we don't know. Right? We don't have a verifiable explanation. I wonder if we ever will.
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  10. #9  
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    Quote Originally Posted by Markus Hanke View Post
    What does that mean, exactly?
    I often use an analogy here which I find rather useful - think of the Big Bang as a "pole" in space-time. Imagine you were to start walking north from your house; you walk and walk, and eventually you reach the North Pole. Then what ? Can you walk further north from the North Pole ? Of course not, because everywhere you face will now be "south". Same in space-time; you go back and back until you reach the Big Bang. Then what ? Any "direction" you face at that event will always be "the future"; you cannot go backwards from the Big Bang anymore than you can go north from the north pole. The concept simply does not make sense.
    While I understand and like the analogy, couldn't something have caused it? I mean, we have grown to accept the common theory that the universe 'began' after the BB. But, suppose something caused it? I do believe in God...but, we won't go down that path for this discussion. haha I am speaking in terms of raw science.

    Or can it be infinite?

    Space-time can be infinite, that is indeed a distinct possibility.
    Okay...that makes sense, then.
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    Quote Originally Posted by jmac217 View Post
    It's more likely that there wasn't "nothing" before the big bang, it's just we have no proof of existence before hand. Time is relative, and therefore our time line started when the big bang did. There has been a finite amount of time since then because we can date it back to 13.7 billion years, but there very well could be an infinite amount of time ahead of us. If we had something to base time from that was before the big bang we'd have a greater perspective, but because we don't it seems that it's the first thing to happen in the Universe - which is highly improbable, though impossible to prove. Everything about time and the beginnings of the Universe is purely speculative, but it's likely that the big bang wasn't the first of it's kind. Our Universe doesn't seem to be very disorderly and whatever exists once usually recurs.
    We can LOOK back 13.7 B years. But can we date it as such? Also, how can it be the start of an infinite period of time when infinity by it's very nature has no beginning or end?
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  12. #11  
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    I read something interesting recently ...I'll have to find the link and post the short article here. But, in discussing this with colleagues, a scientist basically said that when we try to describe nothing...with an adjective (ie: infinite) ...it then actually becomes 'something.' In other words, I don't believe science is suggesting that nothing means anything but that which they don't have an explanation for, through physics. They don't have any knowledge of anything that may have occured prior to or what might have caused (if anything caused) the BB. It's an interesting article, I'll look for it and will post.
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    Quote Originally Posted by wegs View Post
    couldn't something have caused it?
    Perhaps "cause" isn't the correct term, since it implies the existence of time ( and perhaps space ). But I do get what you are trying to say; there are at this point in time too many unknowns to answer this definitively. For example, we are missing a huge chunk of knowledge in that we don't have a theory of quantum gravity yet. Because of that we quite simple do not know what the universe was like prior to some very early point in its evolution. For example, we always talk about the BB "singularity", but no one actually expects singularities to be real, physical objects. Even without such a theory of quantum gravity, one could speculate classically, and start by replacing General Relativity by Einstein-Cartan gravity - the two are identical, except that the latter permits torsion in addition to curvature, whereas the former doesn't. What happens then is that we no longer get a singularity at the BB ( or even in a black hole, btw ), but an Einstein-Rosen bridge. In other words - the Big Bang has become an infinite cyclical Big Bounce model, and extrapolating time backwards simply leads into another "cycle". Thus there would never have been a beginning.

    Another interesting proposal is Causal Dynamical Triangulations :

    Causal dynamical triangulation - Wikipedia, the free encyclopedia

    Here, space-time is simply an arrangement of geometrical simplexes.
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  14. #13  
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    Quote Originally Posted by Markus Hanke View Post
    Quote Originally Posted by wegs View Post
    couldn't something have caused it?
    Perhaps "cause" isn't the correct term, since it implies the existence of time ( and perhaps space ). But I do get what you are trying to say; there are at this point in time too many unknowns to answer this definitively. For example, we are missing a huge chunk of knowledge in that we don't have a theory of quantum gravity yet. Because of that we quite simple do not know what the universe was like prior to some very early point in its evolution. For example, we always talk about the BB "singularity", but no one actually expects singularities to be real, physical objects. Even without such a theory of quantum gravity, one could speculate classically, and start by replacing General Relativity by Einstein-Cartan gravity - the two are identical, except that the latter permits torsion in addition to curvature, whereas the former doesn't. What happens then is that we no longer get a singularity at the BB ( or even in a black hole, btw ), but an Einstein-Rosen bridge. In other words - the Big Bang has become an infinite cyclical Big Bounce model, and extrapolating time backwards simply leads into another "cycle". Thus there would never have been a beginning.

    Another interesting proposal is Causal Dynamical Triangulations :

    Causal dynamical triangulation - Wikipedia, the free encyclopedia

    Here, space-time is simply an arrangement of geometrical simplexes.
    I understand and isn't it a true statement to say that any speculative 'process' that would naturally lead to its formation (let's say a 'white hole' for example), could only exist if they were built into the initial conditions of the Big Bang? So here we are again, back to square one.
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    Quote Originally Posted by wegs View Post
    I understand and isn't it a true statement to say that any speculative 'process' that would naturally lead to its formation (let's say a 'white hole' for example), could only exist if they were built into the initial conditions of the Big Bang? So here we are again, back to square one.
    That's impossible to answer, it may or may not be true. We simply don't know.
    But yeah, it's back to square one
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    Quote Originally Posted by jmac217 View Post
    It's more likely that there wasn't "nothing" before the big bang, it's just we have no proof of existence before hand. Time is relative, and therefore our time line started when the big bang did. There has been a finite amount of time since then because we can date it back to 13.7 billion years, but there very well could be an infinite amount of time ahead of us. If we had something to base time from that was before the big bang we'd have a greater perspective, but because we don't it seems that it's the first thing to happen in the Universe - which is highly improbable, though impossible to prove. Everything about time and the beginnings of the Universe is purely speculative, but it's likely that the big bang wasn't the first of it's kind. Our Universe doesn't seem to be very disorderly and whatever exists once usually recurs.
    I agree with PhDemon that the claim of "likely" is far-fetched.

    Pre-Big Bang ideas are currently speculation only, but it's quite reasonable to consider BB a change of state. Spacetime follows principles we can currently measure and observe, now, but we cannot measure or observe the state, principles of behavior of what may have been a previous state. This does not mean that there was "nothing" or "no time" anymore than it means there were frolicking unicorns and dreamberries.
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  17. #16  
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    Quote Originally Posted by imetheman View Post
    Also, how can it be the start of an infinite period of time when infinity by it's very nature has no beginning or end?
    Infinity can have a start but no end (or vice versa).
    ei incumbit probatio qui dicit, non qui negat
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  18. #17  
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    Quote Originally Posted by Neverfly View Post
    Pre-Big Bang ideas are currently speculation only, but it's quite reasonable to consider BB a change of state. Spacetime follows principles we can currently measure and observe, now, but we cannot measure or observe the state, principles of behavior of what may have been a previous state. This does not mean that there was "nothing" or "no time" anymore than it means there were frolicking unicorns and dreamberries and fairies.
    fixed that for ya. ;=) Your note that 'it's quite reasonable to consider the BB a change of state...'' is very intriguing. I decided to read up on your assertion here, and this is what I found...Big Bang Was Actually a Phase Change: New Theory | Space.com I'm going to open a new thread about this in the other section, as I'd be curious to know what others think about it. Thanks for your feedback, interesting insight!
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  19. #18  
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    Quote Originally Posted by Strange View Post
    Quote Originally Posted by imetheman View Post
    Also, how can it be the start of an infinite period of time when infinity by it's very nature has no beginning or end?
    Infinity can have a start but no end (or vice versa).
    I thought infinity by ''its very nature'' has no end (but obviously has a start)...unlike what imethman is saying?
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  20. #19  
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    Quote Originally Posted by wegs View Post
    Quote Originally Posted by Strange View Post
    Quote Originally Posted by imetheman View Post
    Also, how can it be the start of an infinite period of time when infinity by it's very nature has no beginning or end?
    Infinity can have a start but no end (or vice versa).
    I thought infinity by ''its very nature'' has no end (but obviously has a start)...unlike what imethman is saying?
    It can have a start but no end (consider the positive integers, for example), or an end but no start (the negative integers), or neither a start nor an end (the set of all integers).

    That is considering infinity as an ordinal (defining the size of something).
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