I didn't know if this should go here, or in the GA forum, so I chose here. But, the question I have, is this: Has anyone ever speculated that perhaps our universe has undergone multiple big crunches to achieve the state it's in today? Is it possible that perhaps our universe is in actuality many times older than we think it is, and our universe had to undergo a number of big crunches before it achieved a state where enough energy was pent up to allow it to expand indefinately? I remember reading a book once where the author speculated on universes undergoing big crunches every couple of seconds, and eventually stabilizing into an expanding universe...or maybe I'm wrong. The book was Manifold: Space by Steven Baxter. Very good read, if I might add. At least I think it was Manifold: Space. It could have been Manifold: Time. Anyways, I was just wondering if it was in any way possible that our universe has already undergone multiple big crunches/bangs, and if anyone has speculated on the idea outside of SciFi.

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"Some see the glass half full, some see it half empty, and some see it crawling with toxic alien parasites who want to devour your pancreas." - Sgt Aarhus, from the book Ascending by James Alan Gardner

Many thing that the universe is like a cosmic oscillator. Banging and crunching across the infinitieth dimension. However, that doesn't change the age of the universe because if it did crunch, then that universe would cease to exist and a new one would bang with perhaps different laws, like different values of G, h or c. Stephen Hawking said that asking about what happened before the Big Bang or what will happen after the Big Crunch is like asking what's south of the south pole. It's a nonsense question. So, the universe is only as old as the Big Bang.

Having said that, it could just be a case of complex time. Like the root of negative one. It may lead to a whole new branch of theoretical physics, which it probably already has in the time it took for the software to actually post this reply.

As for the energy bit, that's very difficult to say given the unpredictability of consecutive universes. Conservation of energy dictates that if the one universe didn't have enough energy to be open, neither would the one after. But since we talking hyper-dimensional, those laws may not, and probably do not, apply. The real question is, does one universe have any effect whatsoever on the one after, or even before it?

Reminds me of the Heechee series by Frederick Pohl. In those books, humans discover that there's an alien race, very ancient and powerful, who have learned how to cause a Big Crunch, survive it, and influence the form of the resulting new universe -- presumably to make it more suitable for inhabitation by said race.

OTOH, the same series includes technology that can "drill into" the event horizon of a black hole and come back out... so have the salt handy!

Can't remember I did, no.

But have you ever imagined that the universe is infinitely large in extent and infinitely old?

And you may ask then, why to conclude that?

Cause that is the only way, the universe could possibly be, in a way that the universe is "all there is" and be self-contained.

Every other possibility causes either it to expand, contract or oscilate. But how could that be, if it is supposed to be self-contained?

In an infinite universe, contraction happens eveywhere. That is what we see as stars, galaxies, clusters, super-clusters, and so on.

Yet, we can never see infinitely far away, cause all light coming from infinitely far is in infinitely many ways 'disturbed' ,and in fact we only see the remnants of that light as the CMBR.

Quite amazing isn't it, to conceive of this in a logically self-contained way, without hocus-pocus of 'creation ex nihilo' things, and 'super-natural' causes.

A universe infinite in age violates the second law of thermodynamics. The second law requires entropy to increase as time goes on. For an infinite universe, entropy would have to approach its maximal value. A universe infinite in extent does not change the picture because you can look at the entropy for specfic volumes, or specific masses, and still get the same result.

An infinite time would allow the universe to reach maximal disorder. Since this is obviously not the case, the universe cannot have an infinite age.

I was always wondering, what all this mess around me came from, but now I know! Thanks!
The universe must already have reached it's maximum disordered state, and the universe doesn't even stop to exist! (can there be more disorder then maximum disorder?)

But seriously, why do you believe that?

Aren't you CONVINCED you live in an universe?
Isn't the fact that you live in an universe, and universes don't cease to exist or come into existence from nothing, disproof of your argument?

Given the fact that there is infinite mass and infinite space, what do you suppose is the maximum and minimum ordered configuration possible?

For instance a large cloud of gas is this state less or more ordered as a star which formed out of the gas cloud?

Let us take another example. A cup of tea and a pice of sugar. The sugar cube is well ordered, and once dissolved into the tea, we might not expect this cube of sugar ever to form again, for statistical reasons.

Stars however formed by the laws of gravity go from maximum dissolved states (the gas cloud) to the higher ordered state of a star.

I think you try to use the 2nd law of thermodynamics out of it's context. It can only be applied to FINITE systems, not to infinite ones, and besides, the law of gravity clearly act AGAINST the law of entropy as I showed you.

Nice try though.

I suggest you to study some more about the 2nd law of thermodynamics and entropy (on This page for instance) and tell me how you got to that conclusion.

PS. Same kind of argument of the 2nd law of thermodynamics is used against evolution.
Go figure!

<font size=-1>[ This Message was edited by: heusdens on 2002-11-27 18:12 ]</font>

You have been asserting this in every thread you've posted in. Are you really unaware that this is not a physical fact, but an assumption? You have defined "universe" to be something that is infinite in extent and across time, and then you use the definition to argue that the universe must fit into this definition. But that's completely a priori -- you are trying to make something real, i.e. the universe that we observe, fit into your preconceived concept of an infinite universe. Unfortunately, the observations don't fit your preconceptions.

Fact? This is not a fact, it's your belief. The best interpretation of the facts, as currently known, is that the universe is neither infinitely large or infinitely old.

Another rule you just made up. The second law applies to any closed system (one not experiencing energy flow in or out). This is very definitely applicable to the universe as a whole. By your definition of 'universe', there is no way for any energy to flow into (or out of) the universe, since it's infinitely large. Thus it meets the condition.

Incorrectly. Earth's biosphere is not a closed system; energy flows in (from the Sun and other sources) and out (by radiation into space). But in the case of the universe, the argument is applicable. In fact, you might even say that the existence of the second law is evidence of a finite-in-time universe, because an infinitely-old universe couldn't have a second law to be discovered by its version of a physicist.

(Of course, you could still have a second law in the expansion phase of a cyclical universe, but I get the impression that this is not what you're proposing.)

I find your notion that you can "logically prove" that the universe must be infinite to be totally absurd. The only thing you can prove logically is that a particular conclusion follows from certain assumptions. What you're trying to do is like claiming that water must be a gas because it's made of hydrogen and oxygen. There's nothing wrong with the logic, but the conclusion is worthless because you've missed some critical details.

(Fixed some typos)

<font size=-1>[ This Message was edited by: Donnie B. on 2002-11-27 21:49 ]</font>

The 2nd Law of Thermodynamics argument is an intriguing one, but I'm not sure it works. Funny things happen on the way to infinity.

If you have an infinite state then you also have an inifitiely well ordered ground state from which at an infinitely long period of time ago you started decaying. But as we know, entropy depends combinatorically on states. I'm not up on my mathematical varieties of infinities, but I do know that a measurement that involves arranging particles (that's basically an entropy measurement) is much larger than some aleph-null or aleph-one set. I'm not sure how much bigger and I don't think many mathematicians (sadly) frequent this forum. Someone might try asking over at Straight Dope, but I suspect the answer will be nebulous there too.

My gut instinct is that there are so many different combinations to go through that you don't expect to live in a heat death universe if the universe has infinite extent in space and in time. If it is just inifite in time and not in space then you have a heat death. That's just a hunch though and I could easily be proven wrong.

I wasn't asking whether or not our universe was created. That's a moot point that most of us won't know until we're dead. Either we get judged by Jesus, or we rot in a hole somewhere. That's how we'll know. The question I asked was if it was possible that our universe has undergone a big crunch or many big crunches before. Please refer to post #1 for the exact question. I don't want this post to turn into some huge argument, all I want is a bit of speculation about the question at hand. Not whether or not the universe was created, or if it's infinite. Our universe now may turn out to be infinite. It may very well go on until everything in it dies of a heat death and every proton has decayed. But, that's not what I'm asking. Could someone answer my question, please, in a logical manner and please quit bickering?

BTW, thank you, Glom, for the reply. As you say, laws as we know them today could very well be different for a universe that has undergone a series of crunches and bangs. But, this is purely a speculative question and I'm just curious if anyone has ever thought about it. And, if so, what their take on it is.

P.S. Sorry if it seems like I was reprimanding anyone. I'm not trying to be a d-head (hope that's PC enough), but I realized that the post was veering completely off topic. Some are arguing semantics and completely ignoring the question at hand.

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"Some see the glass half full, some see it half empty, and some see it crawling with toxic alien parasites who want to devour your pancreas." - Sgt Aarhus, from the book Ascending by James Alan Gardner

The question I asked was if it was possible that our universe has undergone a big crunch or many big crunches before.

Another question. part of the big bang was the creation of time itself, so how could there be anything before the big bang?

Tom

<font size=-1>[ This Message was edited by: thkaufm on 2002-11-28 23:46 ]</font>

I am holding on to a definition, in which universe is all there is. What is wrong with that?
Unfortunately we have a definition problem, when we use the term "universe". Sometimes it is only meant that it is the universe as we observe, and sometimes as to the extent what could be there, assuming the universe is bigger then we can see.

My logical conclusion is that, if we can certify at a certain moment that the "universe" (here, I use the context and definition most people give it, namely the observed universe and that what surrounds it and must be theoretically there as an extent of existing spacetime) is not all there is, because it is not selfcontained, then we must conclude there is a higherorder world.
Like the 'branes' world, which has been theoretically assumed.

For which reasons it might well turn out that the "universe" is only a part of the reality in which it is embedded. Or we have to assume that the "universe" just came into being uncaused, without there being a "previous state".
I can live with the fact that the universe as a whole, being all there is, is existent in an uncaused way. It just exists.
But my interpretation of this would be that it therefore would not have a beginning.

But I admit THAT interpretation is more on intuition then on might altogether be untrue. One could also logically reason that the universe has been there all the time, such as to say that existence of the universe means that time must exist, and there was no existence before time began. In other words, the universe has been there "all the time". There was nothing "before" the universe, everything that exists, existst within the spacetimebubble that constitues what we call the universe. Whatever one reasons, this will always contain a problem, we can never get around that. Or we have to admit, the universe started uncaused without a previous state ("from nothing"), or we have to assume a higherorder universe to be in existence, "causing" our universe to become existent....



Everything within the universe has to be thought of as causal, any existing state has a preceding one. But this causality breaks down at the singularity.

The question is merely this I think: do we want causality to be applied only within the universe, or do we want it also to be applied for the universe as a whole.

This would be a kind of logic as to saying that since every team of a football club has parents, also the football club must have a parent.

The condition as that it is infinitely large does not make it a closed system.
Just because the set of natural numbers is infitely large, doesn't mean there aren't any other numbers.
An infinite universe could be embedded or be part of a infinitely larger "hyperverse". etc.

In the example of a gas cloud, forming into a star, what does this mean for the entropy or ordering of the system?

What state is more ordered, the gas cloud or the star?

I am in doubt if one can apply the 2nd law of thermodaynamics in an infinite system.

It's an intruiging question, but I think it's not as simple as you have stated.


<font size=-1>[ This Message was edited by: heusdens on 2002-11-29 08:35 ]</font>

<font size=-1>[ This Message was edited by: heusdens on 2002-11-29 08:40 ]</font>

I see a neverending regression coming on here. When speaking about what caused the universe, if you say there is a higher ordered universe that we're a part of, then someone will ask, "Well, what caused the higher ordered universe?" It's just like the God question. "If God is the creator, and everything was created, then who created God?" It's a neverending regression. All we can do with the information we have is speculate about the beginnings of our universe. We can't say without a doubt that it was "always there", nor can we say that our universe was spawned from another. There's thousands of possibilities, and right now, we just don't have the ability to actually see what happened when the universe came into being. For all we know, God really did snap his fingers and *poof*, there's the universe. Or we could be inside a speck of sand surrounded by billions of other specks of sand on some galactic beach in another universe. Perhaps we're the parallel of another universe. Maybe our universe is nothing more than the exit point of a black hole in another universe. Who knows? These are things we'll probably never know in our own lifetimes. And now, I can't think of anything else to add to this post, so I'll just post it.

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"Some see the glass half full, some see it half empty, and some see it crawling with toxic alien parasites who want to devour your pancreas." - Sgt Aarhus, from the book Ascending by James Alan Gardner

I'd say you chose correctly.

I am quite sure it has been speculated. It is only natural for that question to follow the question of whether our universe is going to experience a big crunch. Who knows? As far as I know, we can only speculate the age based on the oldest (most distant) object we can detect. (Someone who understands cosmology better may be able to clarify this.) Don't worry, the jury is still out there on the exact age of the universe! Interesting proposition. I do not believe we currently have the means to test this kind of hypothesis yet or not. To borrow a quote, anything is possible - improbable or unlikely is another matter. Unfortunantly, until we can find a way to understand what there was before the Big Bang, I do not think we can really tell. The best advice I can give, if you are really curious, is to do a Google search on the big crunch asn see if it shows anything. Even better, if you can get to a university, search the directory of their periodicals and see if any of the science journals have a mention of this.


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"Once again, we find that science is a two-headed beast. One head is nice, . . . but the other head of science is bad! Oh beware the other head of science, Arthur, it bites!" - The Tick vs. Dinosaur Neil

<font size=-1>[ This Message was edited by: nebularain on 2002-11-29 15:14 ]</font>

Thanks, nebularian. One of the few posts that actually attempts an answer of the question at hand. Too bad I can't get to a university around here.....

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"Some see the glass half full, some see it half empty, and some see it crawling with toxic alien parasites who want to devour your pancreas." - Sgt Aarhus, from the book Ascending by James Alan Gardner

Jetmech, as I understand it, this universe will not crunch. In fact it appears that its rate of expansion is increasing not decreasing, and based on what we've known for some time, there doesn't appear to be enough mass in the universe to cause its expansion to reverse.

That doesn't necessarily mean there couldn't have been previous universes oscillating between expanding and contracting. I have thought about it and find it somehow comforting to envision a universal collapse and rebirth as an alternative to cold death when the last star winks out in an ever expanding cosmos. Not that it will make any difference to me which way it goes.

If this universe won't crunch, I guess we are living in the last universe. It may also be the first, but for no particularly scientific reason, I choose not to think so.