I have not done any research on theories concerning the origin of the big bang. My question is more or less a philosophical one. What if the one Big Bang we relate to is a subset of many previous big bangs?
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I have not done any research on theories concerning the origin of the big bang. My question is more or less a philosophical one. What if the one Big Bang we relate to is a subset of many previous big bangs?
Established Member
Suggest a good book
Previous or subsequent?
If the former, that sounds like speculative "cyclic universe" models. If so, be aware that while some such models have originated in the mainstream research literature, the older ones (in some cases, many decades old) are not viable.
(Incidently, you should be aware that various amateur "cyclic universe cosmologies" are frequently promoted on the crankweb; these are not testable theories and are of no interest in science. Typically, their authors admit to being motivated by religious doctrines founded upon some notion of "cyclic processes" as the alleged fundamental organizing principle of life, the universe, and everything (e.g. Buddhism, Theosophy). Contrast amateur authors of non-scientific "cosmologies" who admit to being motivated by other religious doctrines, which stress an alleged unique divine universal creation event (e.g. Judeo-Christian-Islam), or of still other doctrines, which stress an alleged eternal universe (e.g. Hinduism). All these authors promote cranky "cosmologies" which adhere to their personal religious beliefs.)
If the latter, that sounds a bit like the speculative notion of "Baby Bangs". This idea (that a universe like ours might frequently give birth to new universes which are initially very hot and dense and expand to a cool and sparse state like the "current" epoch of the "observable" portion of our universe, and which for one reason or another, Earthly astronomers cannot easily observe) has arisen in a number of contexts. Currently there is (AFAIK) no widespread agreement that any available evidence constitutes compelling evidence for some kind of "Baby Bang".
(If anyone wants to discuss observable or other consequences of a particular "Baby Bang" type speculation, it would probably be good to provide a citation so that there is no question which variety of this idea you are discussing.)
Correct me if I am wrong, but I am taking you at your word when you say that your interest is "philosophical". An excellent and very readable book on the philosophy of space and time which addresses some of the novel issues raised in this venerable topic by the advent of general relativity and the modern theory of dynamical systems (e.g. concepts like Poincare recurrence in relation to the increase of entropy), is:
Lawrence Sklar,
Space, Time, and Space-time
University of California Press, 1977.
This book is also notable for its superb non-technical discussion of Riemannian geometry.
As he noted in the introduction to his second book, when he wrote his first book (just cited), Sklar did not yet fully appreciate the philosophical significance of topics like ADM; I'd add Cauchy horizon and perhaps levels of structure to that. As resident pedant, I should also note that while Sklar's brief discussion of the role of Mach principles (there are dozens of them!) is excellent, there is much more to say.
Unfortunately, these additional topics require mastery of much mathematical background to appreciate.
Last edited by Chris Hillman; 2008-Jun-21 at 05:46 PM.
Member
From my amatuer point of view.
"The" Big Bang could be a constant cycle of "A" Big Bangs expelling all this energy and matter out into the universe, until, a few hundred billion years later, the energy of the explosion disipates and gravity draws all this matter back into the centre until the extreme density produces the next Big Bang.
Also, this Big Bang cycle of ours could be one of an infinite amount of Big Bang cycles going on throughout the universe independantly of eachother.
These cycles could have been going on forever, and could last forever.
Established Member
I assume you were not being serious, but in case you were:Originally Posted by Marauder
- in science, one doesn't just make up numbers out of whole cloth, one has to have some theory and one has to use it to make quantitative predictions,
- aside from "few hundred billion years", your proposal is basically the oldest variety of "cyclic universe"; be aware that "extreme density produces the next Big Bang" was debunked many decades ago.
That is basically one aspect of speculations about hypothetical "Baby Bangs".
Marauder, I see you are a newbie, so unless you have been lurking for some time, there are some forum-related issues you should bear in mind.
If you want to discuss the science of cosmology, be aware that this is highly technical field founded upon some pretty subtle mathematics, so amateurs should be cautious in making sweeping assertions sprinkled with "could" or "will" if they want to talk about science.
On the other hand, if you simply want to casually express your personal beliefs in a non-scientific discussion, in the manner of friends "shooting the breeze" over a beer, fair enough, but please say so. Otherwise more serious-minded BAUTians might waste time correcting/debunking your statements.
Banned
This subject pops up often, and is more to do with your ability to comprehend than facts. 'Chris' has very clearly stated the scientific approach. A In depth study of physics has debunked the cyclic universe. The expansion of the universe is accelerating. Which would make the eventual collapse unlikely.Throw this train of thought away, its wrong.
The statement; Before the big bang is meaningless. Yes, there was a beginning. At that moment time and all that we know of began. While the expansion continues to accelerate there can never be a crunch... or end. About that beginning point we so apply call 'the Big Bang' we know very little of. We are putting together a clear picture of what has happened since. That is all we can ever do. Map the universe, and study the structure for clues of its past. A mission of science ongoing... Mark.
Member
Sorry Chris. I did preface my message with the note "amateur point of view" .
I have lurked around here for a while and have found some very interesting theories and opinions expressed.
Sorry if I offeneded you all, I'll go back to "lurk" mode
Established Member
I'm not sure why Chris, and, and a few others are so touchy about defending main stream astronomy theory. Most astronomy theories would be considered hypothesis in hard science. I've managed to survive at bautforums for hundreds of posts, so you can to. NeilSorry Chris. I did preface my message with the note "amateur point of view" .
I have lurked around here for a while and have found some very interesting theories and opinions expressed.
Sorry if I offeneded you all, I'll go back to "lurk" mode
Established Member
Nobody asked you to stop posting. I did suggest that until you have a lot more knowledge and experience, you probably should avoid appearing to propose a "theory", particularly if you have a sensitive disposition, since all likelihood your idea will appear silly or vapid compared to ideas touted in respectable research journals by Ph.D.s with years of experience.Sorry if I offeneded you all, I'll go back to "lurk" mode
Given that you are an inexperienced amateur, and given that this is Q&A, I suggest that next time you write a post more like this:
See the difference?I have some amateur questions:
Could "the" Big Bang be one in a constant cycle of Big Bangs expelling all this energy and matter out into the universe, until, a few hundred billion years later, the energy of the explosion disipates and gravity draws all this matter back into the centre until the extreme density produces the next Big Bang?
Also, could this Big Bang cycle of ours could be one of an infinite amount of Big Bang cycles going on throughout the universe independantly of eachother?
Could this "cycling" continue forever?
I'm not sure what Neil's problem is, but clearly he has seriously misunderstood my posts.
Both Marauder and Neil should recognize that in my Post #2, in response to the OP's question, I proceeded the same way I answer other such inquiries: I give a thoughtful answer (grounded in knowledge of the field under discussion) and I cite a thoughtfully chosen selection of books which seem to me most likely to provide immediate benefit to the inquirer. IOW, whenever possible I offer serious answers to (presumably) serious questions. As written (in declarative mode) Post #3 cannot be taken seriously. Had it been written as a question, we would presumably not be having this conversation.
Last edited by Chris Hillman; 2008-Jun-24 at 08:31 AM.
Established Member
I sort of agree with Neil. I think its highly dubious hearing people pretend they know anything valuable about the big bang, or what preceeded it. "Singularity" is a fancy word for saying "we dont know what we are talking about". So scientists have admitted they dont understand the physics involved and since they dont understand that then there is not alot they can tell us about it. Hence the silly patronising view that "there was nothing before the big bang" is pure speculation, and no more credible than someone who thinks there have been many big bangs.
This subject is nothing other than speculation and as far as I am concerned in this case, all speculation is equally credible or not as the case may be.
Banned
Its OK to have questions...
Its openly encoraged...
But the OP goes further than that in suggesting a alternate view. Which may not be correct, or is.
My own opinion is obvious ( post 5 )
I do not have an issue with alternate views to mine. ( I might be wrong )
At this time the very best cosmological models do not tend toward a cyclic universe. All the observations yet made by radio and optical, including infrared and x-ray do not show any trend enforcing this cyclic proposal.
If you have evidence for your thoughts please share. mark.
Last edited by astromark; 2008-Jun-24 at 11:26 AM. Reason: Oops...
Banned
As much as it makes some sense to have your view, it is flawed.
We do know what happened after the Universe cooled enough for mater to form. We can and have mapped the cosmic microwave background, and can actually see the expansion rate continuing to increase. We have not found any evidence to support a second generation or multiples of. Not a big crunch. Just expansion. For ever and always.
And one more point. Time when faced with massive gravity has shown to slow. stop even. So its difficult to imagine how anything can be said to happen befor time started. It quite simply just did not exist. Adding to this thought is 'Allowing for multi universes just passes the buck. It simply avoids the question by complicating the issue. Where did that come from and was there a first? all good questions that my answer disqualifies, it does not need to be answered.
Ask me what triggered the Big Bang, and I will tell you I have no idea. But if you ask of what was before it? that easy, Nothing. Absolutely nothing.
Newbie
Chris, thanks for your thoughts. Accepting the premise that there could not have been a previous big bang leads me to the conclusion that before the big bang there was no universe; just a complete void. My question is where did the matter/energy come from to create the big bang?
Member
OK, Chris & Astromark, sorry if my post wasn't structured to your liking (insert winky smily here), however if you re-read it, I didn't claim any of it as being fact, it contains a lot of "coulds" and was prefaced with "From my amatuer point of view". I will try harder next time
My question then is, as JPSG1 said "where did the matter/energy come from to create the big bang?"
Banned
We, that is all of us. Do not know., and may never. It just did. As troubling as that is. That is it.
Excepting that all of everything, being this whole universe might not have had a beginning as such at all. If you could reverse the time line In regard to the fact that as density increased so did time slow at the moment mater did not exist nor did time. There was only a beginning as time began its endless trek. More simply stated as, There was no before.
Member
Thanks astromark.
It's hard to comprehend nothing existing, not even time prior to the BB, but then that's the kind of concept that makes all this 'stuff' fascinating.
Established Member
Astromark,
I was never questioning the science post-bang, just our assumptions about what if anything there was before it.
"Ask me what triggered the Big Bang, and I will tell you I have no idea. But if you ask of what was before it? that easy, Nothing. Absolutely nothing."
The fact we dont know what triggered the big bang; logically also means we do not know whether it is a one-time event, or can happen many times, or an infinite amount of times. But you are inferring it is a unique event as there was *nothing* before it.
I dont think we can safely say there was nothing before it. It happened and something caused it to happen. Or if we believe that a random quantum fluctuation caused it to happen then it is surely reasonable to assume there may be more like them. If once, against incredible odds, why not again in a longer numbers game?
I'm not necessarily ruling anything out. But equally i dont see how we can know there is "nothing" outside our universe, hence we cant know there was "nothing" before the big bang.
Established Member
You are very welcome!
Fair enough.OK, Chris & Astromark, sorry if my post wasn't structured to your liking (insert winky smily here), however if you re-read it, I didn't claim any of it as being fact, it contains a lot of "coulds" and was prefaced with "From my amatuer point of view". I will try harder next time
Just to make sure you understood what I was saying: I didn't say "could not" as in "I can prove this is impossible". I said that there have been several varieties of a "cyclic universe" type model proposed in the mainstream literature over the past fifty years or more, most of which appear to be incompatible with firmly established parts of modern cosmology. I warned that in addition there are many amateur proposals grounded in
- ignorance of the scientific evidence,
- ignorance of the meaning of "theory" or "model" in science,
- religious convictions of the amateur proposer
Actually, there are other proposals currently bruited in the research literature to the effect that there was something before the putative "Big Bang event", without neccessarily proposing some kind of cyclic universe. In particular, "Baby Bangs" need not imply anything "cyclic".
Also, as I keep saying, the standard HBBT takes us back to a much earlier epoch (much hotter and denser than "here and now") but it doesn't really quite say "the universe began with a strong spacelike curvature singularity in the sense of gtr models like the FRW dusts". The reason is that physicists have long had good theoretical reasons to believe that gtr breaks down at very large energies/curvatures, so physicists have long believed, not "the universe began with a strong spacelike curvature singularity in the sense of gtr models like the FRW dusts", but "our current theories are on very shaky ground as we near the putative Big Bang".
Hope that's clear.
I think the best answer is that physicists dunno. They have proposed lotsa ideas, some silly, some not. I think it is fair to say that the question of what happened near the putative Big Bang (much less at even earlier epochs, if any) is currently an almost complete mystery. Some woul d say that string theory provides theoretical evidence for preferring certain possibilities, but I think that may be going too far.
One crucial point which IMO, popular science mags and public science discussion fora tend to do a really really bad job at explaining is which parts of modern cosmology/physics are really solid (like special relativity, HBBT) which are wildly speculative, and which are in between. But as my fumbling for words above shows, to be fair, this is a really hard thing to explain to non-experts, and perhaps only active academically trained researchers in cosmology/physics can appreciate these distinctions.
Established Member
I like M-theory, (which is close to what i have always been told and understood since i was very small.)
M-theory suggests that there are 11 dimensions and in the higher dimensions there exists a (for all practical purposes) "universe" that has membranes of ridiculously ultra high energy encompassing the space. when these "membranes" collide which happens all of the time, they produce an event, or a Big Bang. that event is so energetic that it creates its own space, its own universe where the energy dissipates. The space expands into itself and over time, and the energy released "condenses" into matter and becomes the stuff in the universe, stars, galaxy, planets, what not. A universe is born, has a life and dies when the energy is depleted. Universes pop up and dissipate like bubbles in a bubble bath. This happens all of the time over and over..
Order of Kilopi
Many Worlds In One -- Alex Vilenkin
Everyone is entitled to his own opinion, but not his own facts.
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Interesting article at Physorg:
http://www.physorg.com/news133515283.html
"“Both things, a Big Bang or a bounce, are possible,” Hartle says. “However, we found a significant probability that the early universe might have bounced.”
Hartle does admit that the simple model used by him and his colleagues does have its limitations. For one thing, the universe is not completely homogenous as the model assumes. “You see a certain lumpiness in the real universe,” he concedes. However, most of the irregularities are small, and many of them can, in fact, be ultimately accounted for in a no-boundary proposal.
“Our model does make a number of strong assumptions,” Hartle continues. But, he insists, “this is a standard trade-off in physics. Our model is simplified so that we can analyze it completely.”
“In present cosmology, we test models to see if different proposals fit the universe that we see. In this instance, we see that the no-boundary wave function does,” Hartle says. “We see that there is a good chance the universe originated in a bounce.”
“We hope that can extend this to other, more sophisticated models, with different potentials and different degrees of freedom.”
Banned
This subject more than any other seems to draw out the ' But what if ' mentality. Now firstly let me make it perfectly clear.... I do not know ... I do not know that this is the only universe. I do not know that it has not rebounded from a previous contraction. I do not know... BUT nor do you. The tendency to over complicate this Big Bang idea which is as simple as it can be made. Is troubling. I have always liked the thought of 'the simple idea is the most obvious and therefor the most likely.' This need to complicate is more to do with humanities inability to except the obvious than a search for the truth. I know some thing you lot do not... wrong. You might well think you do, but can not prove that. To have the last word in this debate is easy... all you need to do is except that we do not know everything. Building complex models may test your imagination. It proves nothing. A 'You might well be right' is the best answer here. While secretly thinking that you might well be wrong as well. If you still want to argue this BB idea then look again at post 14. Thats hard to refute. Do not let my ranting stop you. Its entertaining.-
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