Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

No time before big bang.

  1. Oct 23, 2011 #1
    Would it be true to say that if we believe the big bang theory, and we believe the best current theories, then there is no such thing as before the big bang because time was born at the big bang?

    Accepting that the universe started from a near infinitely dense and hot object smaller then an atom.

    Thank you for your answers.
     
  2. jcsd
  3. Oct 23, 2011 #2
    Well, if time was ' born' at the big bang then there would have to be a Mrs. Time , its mother, and a Mr. Time, its Father. :biggrin:I am tired.:zzz:
     
  4. Oct 23, 2011 #3

    Chronos

    User Avatar
    Science Advisor
    Gold Member

    Yes, that is the prevailing notion. The universe began in an immensely hot and dense state that expanded exponentially in the blink of an eye. BBT only applies after the first tick of planck time, it makes no attempt to describe the state of the universe prior to this point.
     
  5. Oct 23, 2011 #4

    DaveC426913

    User Avatar
    Gold Member

    So, to answer your question, no, BB does not say that there was no such thing as before BB. It is silent on the subject.

    There are some highly speculative hypotheses about what might have been around before the BB but its anyone's guess.
     
  6. Oct 23, 2011 #5

    Ken G

    User Avatar
    Gold Member

    I agree, in fact I would argue that we run into trouble as soon as we invoke language like "if we accept the model, then what does it say about...". That kind of language has to be used very carefully, because it has rather the same flavor as a gedankenexperiment. I would argue that sometimes it is suggested that gedankenexperiments are ways to understand what reality is like in some impractical but potentially possible scenario, but that is never really what gedankenexperiments are-- they are always ways of putting a question to a theory. If you want to put a question to reality, there is only one way to do it-- come up with an experiment that poses that question to reality. So, we can say that no one has ever come up with an experiment that can put the question "did time exist before the Big Bang" to reality, so we are stuck with putting the question to our models. But when you do that, all you ever find out about is your models, you see your own models better. In this case, what we see about our models is they are rather silent on the whole issue, not only on time before the BB, but also a Planck time afterward.
     
  7. Oct 24, 2011 #6
    as far as the current BBT model is concerned--No there was no existence of either Time or Space before BB.
    it might surely sound weird to even imagine of a primeval atom existence without space n time, but thats where our common sense interferes where we readily imagine of any entity placed in a three dimensional space and at a particular point on the timeline,--- But then consider this, that actually we are dealing with the "origin" of our cosmos(and BB as the moment it came into existence) which simply implies that "each n every" thing homosapiens can perceive regarding their universe came into existence- including Space n Time and other dimensions as well.
    So we can say that for us BB was the Eternal beginning of "our" cosmos.

    Yeah i do believe in some kind of Hyperspace(n perhaps Hyper-time as well) but i think that existence and observance of a being is confined to the universe it belongs to, as our sole existence might be possible only under the domain of our universe ONLY.

    so even we if we think of some Eternal/absolute Time(a timeline on which we can place our BB n others if possible) is completely of very less concern n infact meaningless, HOWEVER it will be of prime importance to a hypothetical being who can access many higher dimensions and whose existence can be defined in hyperspace.

    It is similar to the case, where for all beings of a two dimensional universe thinking of another similar 2d universe just close to them is of no use as their existence is not defined in the third dim., but for a being like us(who can access to 3rd D) its quite easy to access both universes.
    The same case of Space applies to Time as WELL(atleast i think so).
     
  8. Oct 25, 2011 #7
    What I would like to ask, how to properly explain under which specific theory does time begin with the big bang?

    Because from what I've read, a lot of astrophysicist, seem to say that's when time began, and there is no way we can even speak about "before" and in many instances there can be no such before.

    I have read an extremely good article on quantum mechanic that was saying that time didn't even have a "first moment" it was complicated as usual with QM but they were saying that spooky things happen in QM, and that the "first" moment would be nearly impossible to pin-point, but we'd know time has started tho.

    Sorry if I'm not vulgarizing things correctly. thats how I understood it.
     
  9. Oct 25, 2011 #8

    DaveC426913

    User Avatar
    Gold Member

    The theory that purports this is the Big Bang Theory. It purports that space time - all four dimensions of our current universe - were created in the Big Bang.
     
  10. Oct 25, 2011 #9
    Your first answer left me wondering, because I read that if we follow that premise, then there is no such thing as time before the big bang.

    Where was I lead wrong?
     
  11. Oct 25, 2011 #10

    DaveC426913

    User Avatar
    Gold Member

    That is correct. You were not lead wrong.

    Isn't that what I wrote? Time was created in the BB.
     
  12. Oct 25, 2011 #11
    BBT simply says that the "very" first event of our cosmos was the Big bang. And that implies that all the set of events were followed by it.
    Now our 4th dimension-Time is nothing but a dimension that accounts for just occurrence of events (suppose if any how you can stop "each n every" event of the entire cosmos- the river of time just freezes), and hence if we conclude the BB to be the "very" first event, then its perhaps pointless of thinking of any time 'before' that(atleast until we comeup with some other model)
     
  13. Oct 25, 2011 #12

    Ken G

    User Avatar
    Gold Member

    "Led", not "lead." (Pet peeve-- I hate to see the passing of the word "led".)

    Also, BBT does not say anything about the "first" moment. It is not a theory of origin, it is quite demonstrably a theory of evolution. (All the physics that goes into it is a theory of evolution, and all the observational tests that have been applied have been used to test evolution.) It is an evolutionary model where time runs backward from the observations we have, and that backward-running time never gets to a first moment, because all the theories we use to constrain that evolution break down before we get to any "first" moment. Hence, not only does time before the BB have no scientific meaning within our current physics, neither does a "first moment" have any meaning. There is no first moment in the BBT, and indeed this is one of the most important and brilliant aspects of that theory-- it anchors what we don't understand in what we don't expect to have a theory for, saving us from inconsistency.
     
    Last edited: Oct 25, 2011
  14. Oct 26, 2011 #13
    Thanks Ken G for making it clearer on the "first" moment.

    But still it looks abit fuzzy as far as the first "event" is concerned- as BBT is certainly a theory of cosmic evolution- and with "BB as the origin of our universe" as one of its major aspects(absolutely this model purported by BBT is based on observational test and evolutionary model), although i completely agree that any of the current physics ceases to explain the very "first" moment(even its not certain if any physics exists at that moment).

    All this can be easily(thats how can conviniently putup my thoughts) understood by the following example:
    Consider the flow of a river and some form of being in the middle of the of its flow, where the flow is gentle-calm-smooth and "Deterministic" as well. so observing the vicinity of the flow, and rendering their motion into natural laws and evolutionary models, they finally comeup with a BST(big Splash Theory) which perports of (a very violent) source/origin of the river(might be a turbulent one like say waterfall/giant geysor etc) which might not hold any of the laws they have fabricated so far, BUT there is certainly an Origin of the river before which it doesnt exists and so being "river-beings"(assuming land to be hyperspace) its pointless talking about anything "before" the origin/source (although talking about the very "first" stream of water molecules at source is of no meaning as well).

    {please accept that my percerption on the entire BBT might not be crystal clear, but thats what i can draw from it}
     
  15. Oct 26, 2011 #14

    DaveC426913

    User Avatar
    Gold Member

    Concurrence. I pained me to write that, but I felt changing the writer's words would have confused the message.
     
  16. Oct 26, 2011 #15
    iF Time is infinite,the BiG Bang may just be an infinite event in Time..what if we were within a black hole before where Time had be regenerated in to a new Being,,,,,(?) + continuously will end up being in Another..
     
  17. Oct 26, 2011 #16
    There is no concept of T=0 in the BBT. That doesn't mean T=0 doesn't exist. It just means that the theory, and the prevailing cosmological models based on it, can't account for it conceptually or mathematically. I personally believe T=0 exists, and furthermore T<0 as well, but you have to look to cyclical cosmological models and multiverse theories to account for such variables, along with new mathematics and quantum theories, either as replacements for BBT or as complementary partners. Unfortunately, no matter how much we learn, I don't believe we can ever find out what happened at the beginning of "everything", as you can always ask how the initial conditions came into being. Philosophers might have better answers than physicists at that point.
     
  18. Oct 26, 2011 #17
    In this universe Time erupted when expansion started.,we can't talk about before with standard mathematics,,its like saying how was ur yesterday two days before tomorrow started..however,if ∞Time there is,,BBT may be just another bubble of that +infinity,,,and philosophy might just help indeed.. ;)
     
  19. Oct 27, 2011 #18
    I think examples like this over-exaggerate the difficulty in expressing T = 0 and T < 0. If time existed before the Big Bang (as I think it does, but not in our incomplete model), then our mathematics will be able to model it as well. Our mathematics are fine; it's our constants, our distance measurements, and our spatial dimensions that could change. But I believe 2 + 2 will always equal 2, before the Big Bang and afterwards. But whether the speed of light is the same, or whether the Higgs particle would exist, or whether we would have 3 dimensions or 11 or 53, or whether the weak force or λ would be the same is another matter. Mathematics works in all times, in all universes, before Big Bangs and afterwards. It's the constants and properties of those universes that might change, not the underlying mathematics. So I think we can talk about before bangs and whatnot with math, we just can't talk about specific intervals where matter was too dense to model. In other words, we can create mathematical models of cyclical universes that expand, contract, crunch, bounce, and return just fine, but we can't talk about specific moments when the crunch and bounce occur because our Quantum Theory isn't quite there yet. There are far too many physicists working on alternative models of the universe too just write off talk of "before" as nonsense, mathematically or otherwise. The physicists working on this have more experience than most of the posters in this forum (myself included!).
     
  20. Oct 27, 2011 #19
    Mathematics can describe our universe from BB and on..based of on these laws of nature physicist built models to describe it.I think Time being infinite includes Time before the BB.The mathematics, can't describe it yet ,not because they are not fine nor because it doesn't exist but because we are not there yet in the QF..as u said,,different constants and properties,different intervals,different results.
     
  21. Oct 28, 2011 #20

    Chronos

    User Avatar
    Science Advisor
    Gold Member

    While the universe may have possessed pre-emergent properties, it did not include properties we would recognize as space, time or energy.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: No time before big bang.
  1. Before Big Bang (Replies: 17)

  2. Before the big bang (Replies: 5)

Loading...