Is the Universe Infinite? Theories and Considerations

[NowIsForever]

What do current theories have to say about any resolution to this question? The visible universe might be finite, but that says nothing about the totality. Should we include the Multiverse in this discussion (if there are many worlds)? What about the nature of quantum foam? Could that have a finite basis. And on and on... Is there any end to it all?

 

[Nabeshin]

Judging from the WMAP data, we deduce that the universe is extremely close to being spatially flat. In the standard FRW cosmology, a spatially flat universe is infinite.

 

[Passionflower]

Judging from the WMAP data, we deduce that the universe is extremely close to being spatially flat. In the standard FRW cosmology, a spatially flat universe is infinite.

The question whether space is finite or infinite is not related to whether a spacetime is open, flat or closed. For instance a closed spacetime could be infinite and a flat spacetime could be finite. The fact that FRW models cannot handle finite spaces is obviously not a valid argument here.

 

[filegraphy]

Welcome to Physics forum. That question has not been answered yet. My view of the universe is that it will expand forever. Therefore being infinite.

 

[NowIsForever]

My view of the universe is that it will expand forever. Therefore being infinite.

If the time component of space-time is infinite, then indeed the universe must be infinite even if the space component is finite every step of the way. Although, then the space component could be potentially infinite.

 

[NowIsForever]

...a flat spacetime could be finite...

I don't see how a flat smooth manifold would not be infinite (although perhaps that is a failure of my imagination). Maybe you refer to a non-smooth model? Could you give an example of such a model embedded in Rⁿ?

 

[fouvy]

Welcome to Physics forum. That question has not been answered yet. My view of the universe is that it will expand forever. Therefore being infinite.

It seems that there is no relationship between expand forever and infinite. For example, the tree is growing forever but it isn't infinite high for the reason that the time isn't infinite long, is it?

 

[Chronos]

A tantalizing question. My gut instinct is we will never entirely resolve the question of flatness. CMB anisotropy gives us conficting hints. Too close to call, IMO.

 

[Emu]

As Chronos mentioned in the thread " Why is Space Black"

Olber's paradox, not enough galaxies and stars to fill in the gaps. Olber deduced our universe cannot be both spatially and temporally infinite.

 

[George Jones]

I don't see how a flat smooth manifold would not be infinite (although perhaps that is a failure of my imagination).

A space can be flat and compact if it is not simply connected.

 

[robheus]

As Chronos mentioned in the thread " Why is Space Black"

The Big Bang has taken care of that issue, you can not resolve the issue of finiteness/infiniteness of space and/or time from that paradox.

I think the question is even theoretically unanswerable, and we just use the gut feeling that spacetime is unbounded (there is no *edge* to spacetime) but that also leaves the issue of finiteness/infiniteness open.

My gut feeling is that spacetime is infinite.

 

[TrickyDicky]

My gut feeling is that spacetime is infinite.

How could it be? maybe spatially, but, doesn't the Big Bang make it time-finite, at least in one direction?

 

[robheus]

How could it be? maybe spatially, but, doesn't the Big Bang make it time-finite, at least in one direction?

Nope. There is nothing in the Big Bang Theory that implies that. The Big Bang Theory is not an explenation of the origins of the universe, but of it's development.

 

[robheus]

On the subject of infinites in the realm of physics, you have to be careful about some subtle aspects of infinites. First of all, real infinites (like the mathematical infinite) do not belong to physics. Any measure in physics always is of finite proportions. However note that this does not preclude that space and/or time cannot be infinite.
Look at it like this: consider the natural numbers and select a number. Now, whichever number you came up with, it definitately is a finite number, and also, you can always select a number bigger then the number you just selected.
So the seemingly contradictionary conclusion is that you can select an infinite amount of numbers, yet no number you ever get is itself infinite. Infinite itself is not considered a number.
The infinite exists only in the forms of finite elements.

So, if we consider space-time like the set of all possible spatial and temporal measures that can be made, the set itself is clearly infinite, although any element in the set is of finite measure.
There does not exist a point in time or space infinitely far away.

 

[Andrey]

On the subject of infinites in the realm of physics, you have to be careful about some subtle aspects of infinites. First of all, real infinites (like the mathematical infinite) do not belong to physics. Any measure in physics always is of finite proportions. However note that this does not preclude that space and/or time cannot be infinite.
Look at it like this: consider the natural numbers and select a number. Now, whichever number you came up with, it definitately is a finite number, and also, you can always select a number bigger then the number you just selected.
So the seemingly contradictionary conclusion is that you can select an infinite amount of numbers, yet no number you ever get is itself infinite. Infinite itself is not considered a number.
The infinite exists only in the forms of finite elements.

So, if we consider space-time like the set of all possible spatial and temporal measures that can be made, the set itself is clearly infinite, although any element in the set is of finite measure.
There does not exist a point in time or space infinitely far away.

The infinate exist only in the forms of finate elemetns

This is not entirely true but i can see where you are coming from. Yes the infinate can be measured using finate elements, i.e. your number example. But let's say there are no numbers left to pick. Let's say that there is no finate elements which we can use to measure the infinate, the vastness of space. What do we get then? Well, absolute zero because there can be no set of elements that can define the measurement. Furthermore, you can't even call it Zero for Zero is a measurement of some sort. In fact it is utterly impossible to measure something without giving it a set of measurment, i.e. distance, time, dimention, space etc. Thus don't think of Universe being a set of simple measurements that one can simply use for one's own convenience because the moment you do that, you've restricted yourself from the bigger picture.

 

[heusdens]

(heusdens=robheus)

Perhaps anyone familiar with the Kalam Cosmological Argument. It's a famous but false argument against the infinity of time. The argument goes something like this: if we suppose that time did not have a begin, we could have never arrived at the moment of "now" because it is impossible to have traversed an infinite amount of time.

For people that do not immediately grasp the incorrectness of the argument, just ask yourself, at what point on the time axis is it supposed that we have started the traversal of time.

The point is of course, that wherever you have chosen to start traversing the time axis, you already smuggled in as a premise that time had a beginning, since else, you could not have started traversing the time axis at all.

The only validity of the argument is that there is no point on the time axis in the distant past that is infinitely far before the present point in time, since we cannot traverse an infinity of time. [ and pls. note, that is just what infinity is by definition, that it can never be exhausted or completed, no matter how hard or how long we try. A "completed" or "exhausted" infinity is nothing more as a contradiction in definition. ]

Yet, at the same 'time' this is not to be held against the infinity of time itself, since we can always design a point farther back in time on the time-axis, and thus show that there is no upper limit to a past point in time.

 

[POWERSHIFT]

If the universe was infinite, wouldn't it, according to the 2nd Law of Thermodynamics, have no heat? And if it isn't infinite, that means it's finite, and thus had a beginning. Which also means time had a "beginning." So to speak

 

[heusdens]

If the universe was infinite, wouldn't it, according to the 2nd Law of Thermodynamics, have no heat? And if it isn't infinite, that means it's finite, and thus had a beginning. Which also means time had a "beginning." So to speak

That is a famous arguments from the creationists, they say that (acc. to physics) the world needed to have a beginning, based on the 2nd law of Thermodynamics. However, their idea clearly contradicts the 1st law of Thermodynamics, which claims that the total quantity of energy in any system, is constant, and thus no creation or destruction of energy is possible.

The issue onhand is however much more complicated. Based on E=mc^2 the 1st law of Thermodynamics we need first to consider physical matter too, so the total quantity of both physical matter (mass) and energy is a constant.

Second, both laws of Thermodynamics were originally constrained to laboratory scale thermodynamic systems which were closed and had a thermodynamic boundary. The 1st law (in it's contemporary form, based on GR and QM) still holds for all systems, including the universe. Physical matter creation, as what happened on a mass-scale in the early universe, does not contradict that, because it was a conversion of energy in another form.

The problem with the 2nd law of Thermodynamics however is that it is still constrained to thermodynamic systems which have a thermodynamic boundary.
This does not apply directly to the universe, because apart from the cosmological issue of open or closed universe, there is in the strict sense no thermodynamic boundary to the universe. There's no border or boundary to the universe (cosmological principle), and that is true even when the universe turns out to be a multiversum.

In the Thermodynamic sense the observable universe is an open system, since it does not have a boundary and is in thermal contact with the rest of the universe, beyond our horizon.
For the universe in total the terms open or close with respect to it's Thermodynamic behaviour makes no sense since there is no boundary to the "rest of the universe" (since the total universe already encompasses that) so that it is neither open nor closed.

But there is also something else peculiar about the universe. You might have seen these pictures of a sequence of moments of time in which a gas in a container spread outs through the container (due to entropy or the 2nd law of TD) and becomes uniformly spread through the container.

At the microscopic level however, all physical laws work both ways, so how do we know the progress of time? When we have to order the pictures (let's say there are 3 pictures, one with local concentration(s) of molecules, the next with a medium spread of those molecules in the container but not yet uniform, and the third a uniform distribution) we would clearly say that the progress of time is from picture 1 to 2 to 3.

Yet, when this picture was not of a small gass container, but was of cosmological size, we would need to arrange the pictures in the opposite order! Due to gravity, local matter clumbs together forming stars, galaxies and clusters of galaxies.
So if we were not told what scale the picture represent or that the scale is a varying quantity, we could not say what the right direction of time was!

In the example of the cosmological progress of distribution of matter, there are two important differences with the example of the small gas container. First, the progress of time is from a uniform distribution towards local clutterling of matter, forming galaxies, stars, etc., and the scale of the 'container' grows, due to cosmological expansion.
In terms of entropy, this in fact means that the growing metrics of space allow for more possible states, so this in fact means a lowering of entropy at a cosmological scale!

If you search online, you might find a lecture of Roger Penrose on this issue of cosmological expansion and entropy, which is very interesting.

This is just some basic information, the issue itself is far more complicated as I can explain, but at least I think you get the basic idea that you can not simply scale up our laboratory scale experiment and conclusions based on the 2nd law of Thermodynamics to cosmological scales.

I don't give a proof of it, but one could suspect that on truly cosmological scales (the universe as a whole) the issue of entropy is different as expected, and might lead to the conclusion that entropy is a conserved quantity throughout the cosmos, even if at local scales the 2nd law still applies.

But perhaps someone else more educated on this subject can explain more details.

 

[jackmell]

What do current theories have to say about any resolution to this question? The visible universe might be finite, but that says nothing about the totality. Should we include the Multiverse in this discussion (if there are many worlds)? What about the nature of quantum foam? Could that have a finite basis. And on and on... Is there any end to it all?

Your questions of "finiteness" and "end to it all" restrict the possibilities I believe. 2000 years ago, a farmer would have thought walking far enough straight-ahead would result in falling off the "end" of the world. But in fact, something qualitatively different than "flat" emerges at a large enough scale. Can that also be true of the Universe as well? At a large enough scale, our local concepts such as distance, size, and volume may loose meaning as something qualitatively different emerges. I know that's hard to imagine but it would also have been hard to imagine to the farmers long ago how the Earth could be a sphere and not flat.

To me, I find that possibility comforting: I no longer wonder how large the Universe is, how it started, and where it's going. I simply believe it is likely, based on historical trends such as the flat earth, wandering planets, moving sun and moon and milky-patch in the sky, as well as all the other critical-point phenomena I see around me, that perhaps something qualitatively different then our current understanding of the world is needed to answer these questions.

So my answer is that it may be neither finite nor infinite but rather something qualitatively different.

 

[heusdens]

Your questions of "finiteness" and "end to it all" restrict the possibilities I believe. 2000 years ago, a farmer would have thought walking far enough straight-ahead would result in falling off the "end" of the world. But in fact, something qualitatively different than "flat" emerges at a large enough scale. Can that also be true of the Universe as well? At a large enough scale, our local concepts such as distance, size, and volume may loose meaning as something qualitatively different emerges. I know that's hard to imagine but it would also have been hard to imagine to the farmers long ago how the Earth could be a sphere and not flat.

To me, I find that possibility comforting: I no longer wonder how large the Universe is, how it started, and where it's going. I simply believe it is likely, based on historical trends such as the flat earth, wandering planets, moving sun and moon and milky-patch in the sky, as well as all the other critical-point phenomena I see around me, that perhaps something qualitatively different then our current understanding of the world is needed to answer these questions.

So my answer is that it may be neither finite nor infinite but rather something qualitatively different.

For your last remark, we could refer to the analogy of the theoretical issue wether or not matter was infinitely divisible or not. Some philosophers argued pro, the other against.
What we found - indeed - was neither, as per quantum mechanics and the uncertainty principle. You can split molecules, and then atoms, but when we try to split protons or neutrons into their individual parts. we need such energies to overcome the quark gluon force, that this energy will create new particles.

 

[Physics-Learner]

(heusdens=robheus)

Perhaps anyone familiar with the Kalam Cosmological Argument. It's a famous but false argument against the infinity of time. The argument goes something like this: if we suppose that time did not have a begin, we could have never arrived at the moment of "now" because it is impossible to have traversed an infinite amount of time.

For people that do not immediately grasp the incorrectness of the argument, just ask yourself, at what point on the time axis is it supposed that we have started the traversal of time.

i think it is an absolutely valid argument, as to why the universe had a beginning.

according to the bbt, matter, space, and time were all created by this process.

the singularity is not a part of this universe. no physics explains the singularity. all theories start at nanoseconds after the big bang.

a very common thought process is that the super-universe is responsible for many such big bangs creating many other universes, which may or may not have the same sorts of laws that our universe does.

which is why the question "who created god" is not necessarily a valid question. because it assumes that the super-universe has the same qualities as our own.

time may or may not exist outside of our universe. same is true of matter, space, causality, or any other such notion that we have come to accept about our own universe.

 

[daniel rey m.]

I'd never ever come across the name "Kalam Cosmological Argument". It happens to be identical to one that Immanuel Kant, the German philosopher, presented along with the opposite argument, and in so doing he proved that there's a paradox involved and so there's no logical way out and one can "prove" that both arguments are right. Infinitude and eternity are inherently paradoxical concepts. His reasonings (in his work THE CRITIQUE OF PURE REASON):

Thesis
The world has a beginning in time.

Demonstration
In fact, let us suppose that the world does not have a beginning in time: that being so, up to any given moment there will have elapsed an infinite series of states of affairs of the world that follow one after the other. Now, the infinitude of a series implies that it can never be completed through consecutive syntheses. Consequently, an elapsed infinite cosmic series is impossible and, thus, a beginning of the world is a necessary condition of its existence, which is what we set out to demonstrate...



Antithesis
The world does not have a beginning in time.

Demonstration
In fact, let us suppose that it does have a beginning in time. Since the beginning is an existence that is preceded by a time when the thing is nonexistent, it is necessary that there will have been a time when the world was not, in other words, an empty time. Now, in an empty time it is impossible that anything can spring forth, because no part of that time bears, in respect of some other part, any distinctive condition of existence that is preferential as compared to nonexistence...consequently, even though various series of things can have a beginning in the world, the world itself cannot have a beginning and, thus, it is infinite in respect of time past.

 

[Physics-Learner]

the problem with the second part of that argument is that time is only known to exist in this universe. the big bang started the universe, and created the space, time, and matter that we know today.

without doubt, this universe had a beginning in time. whether the super universe has time or not, or anything else or not - no way we can derive. we simply can not NECESSARILY know anything about the super universe WITH SURETY based upon what is in our universe.

the "empty time" that kant would have been referring to is something about the super universe, because there was no universe of ours during "empty time". thus no arguments are valid during "empty time".

 

[Tanelorn]

Does time actually exist at all, even in our own universe? Is it a property of our universe rather than something material which actually exists?

http://en.wikipedia.org/wiki/Time

 

[daniel rey m.]

Tanelorn, yes, time is another one of those incomprehensible concepts they've been discussing for the last two millennia or more, without getting anywhere.

Physics-Learner, the real problem with that second Kantian argument is that the concept of "empty time" is incomprehensible, so that any reasoning that includes it is incomprehensible as well. He assumes that it's a concept with a corresponding counterpart in reality, rather than what it really is, namely, an empty concept, a mere expression with no meaning to sustain it.

As you say initially concerning the Kalam Argument (Kant's first argument), it's convincing, but so are the reasons for believing the opposite: that there can be no beginning and no end as concerns both space and time.

You're making too many assumptions, and as they say, when you ***-U-ME you make an A** of U and ME. Your basic assumption is the foundation of the Big Bang Theory: the existence of "singularities". This is supposed to explain the extravagant notion that something can spring forth from nothing.

They've been discussing this too for more that two thousand years, and the conclusion was that "ex nihilo nihil fit", meaning "nothing can come out of nothing".

Once you develop the concept of "time" you can't have it both ways and you have to accept that there must ALWAYS be a previous instant. Scientists try to push aside this inevitable conclusion by saying that there is something so singular that it explains EVERYTHING, even the twin absurdities according to which 1) there is a point in respect of which there is no "before", and 2) there is a mysterious barrier all around us beyond which there is nothing, so that we're part of the big Blob of Everything that is submerged in a Sea of Nothing. They claim that the Universe is expanding into nothing because space invents itself as it goes along. None of this makes any sense. You're happily jumping on the bandwagon and you'd rather believe that it's the underdog who is mistaken. The BB Theory simply happens to be the dominant one at present. Not all astronomers go along with this theory.

The situation is exactly as it was about 2,500 years ago, when the Greeks thought that there was nothing beyond the last crystal sphere of the Universe (the one with the fixed stars, as opposed to the wandering stars, called"planets" or wanderers), neither space nor matter. What ultimately explains both this and your finite BB Universe is a terror of eternity and infinitude and the impossibility of grasping these two fearsome matters.

 

[Physics-Learner]

you do not have to accept that there was a previous instant. "time" could very well have formed from something (it is typically referred to as the bb and the singularity).

i think if we ever actually could understand our own universe, concepts of time, speed of light, etc. would become much clearer.

i don't think there is anything inherent about time that says it must have an ending ? but it certainly had a beginning.

as i said previously, something before the beginning would be describing the super universe. time may not exist at all in the super universe. the second part of the argument assumes things about the super universe, and this is where it fails.

as far as we know, time is something that we are experiencing in the creation of our universe. what time is, as has been previously stated, is still a mystery.

 

[daniel rey m.]

"(...) but it certainly had a beginning." You keep repeating that as though you were a preacher waving the Holy Writ. I could just as legitimately say "but it certainly had no beginning".

 

[Chronos]

A "Beginnng" is a relative term. This universe, by all current observations, appears to have originated about 13.7 billion years ago. That does not exclude the possibility of prior universes [e.g., as in bounce cosmologies]. It does, however, make it difficult, if not impossible, to observe evidence of prior states. There is, however, a finite possibility some faint trace remains hidden on large scales the cosmos. We have good reasons to believe the big bang singularity is a mathematical artifact in our theories, not a naturally ocurring state in nature [and probably true of black hole singularities as well, imo].

 

[Physics-Learner]

hi daniel,

let me repeat. the universe had a beginning. the first part of the argument is absolute truism. i am not using the big bang as an assumption. it is one theory about the creation of the universe.

i am simply using the physical manifestation created in our universe that we refer to as "time". there is no way a finite being can exist in a universe which had no beginning, for the reasons already stated.

we experience "time" as a duration, but there is nothing in this universe that points to time needing the quality of no beginning. every object in this universe had a beginning. so it might not be too surprising that our universe has one.

there could be indeed bounce cosmologies. to me, that is just another way of describing the super universe. i simply say that there is some process by which the super universe created our universe. it certainly seems probable that our universe is not the only universe that has ever been spawned from this process.

but whether we use the big bang, bounce cosmology, or any other process, there is no way for us to know that any other universe is like our own. for all we know, there may be a gazillion different combinations and permutations of possible universes with their own unique laws, that could be made.

all we know is our own. and IT IS IMPOSSIBLE for us to have ever been born if we had to wait an infinite amount of time. that is as clear as the noses on our respective faces. one does not need a holy writ to figure that one out.

 

[daniel rey m.]

Chronos, you believe that the BB singularity is just a mathematical entity, an imaginary and ideal creation of the mind such as the point, the line and the plane (location without magnitude, length without width and length and width without depth, respectively, which are impossible objects), but you also believe there was a BB, and in possible previous universes. Would you please make up your mind?

The idea that everything sprang forth from a mathematical point was first put forward by a Jesuit priest, in other words, by a mystic. Why this notion was later taken up by atheists or agnostics is hard to understand. They adopted that belief and then they tried to make all their data fit what had been preconceived.

Physics-Learner, one of your several inconsistencies is that you mistake the whole for the part when you say that "there is nothing in this universe that points to time needing the quality of no beginning. Every object in this universe had a beginning. so it might not be too surprising that our universe has one."

This is called the "fallacy of composition": assuming that the property of a part must also be a property of the whole. This reasoning is valid only in simple, spatial circumstances, as when one says that if all the constituent parts of one's radio are in a drawer then the radio must be in that drawer. The Universe is far more complex than any of its contents. Its ultimate nature remains completely unknown. In this particular case "the whole is greater than the sum of its parts." (Not to be confused with Euclid's rule that says, "The whole is greater than the part.")

Moreover, you insist on postulating the existence of something you call "the Superuniverse". You can't explain to me what the Universe is and even so now you're inventing something that I guess you conceive to be something like the Mother of All Universes. By doing this you're merely translating all the unexplained matters to that other entity. First deal with the daughter, then we can go for the mother.

Then you claim that "IT IS IMPOSSIBLE for us to have ever been born if we had to wait an infinite amount of time". I don't see how you reached that conclusion.

Besides, even if one believes in an eternal Universe, one can imagine a level of reality where there is no such thing as "time", and in this timeless existence everything would be simultaneous, both the past and the future, like the images on a film or a tape. Experiencing life as we understand it would be like being forced to sit down and see the film, scene after scene, but all that we then see as a succession of happenings was always there and will remain there forever, and what we see on the screen is just an illusion. Every instant in our lives would be like a single frame on film --an infinitesimal slice of "time". As we go from one instant to the next one we feel that we're moving forward, but it would be an illusion of movement.

Tanelorn seems to be talking about this when he says, "Does time actually exist at all, even in our own universe? Is it a property of our universe rather than something material which actually exists?"

Time can be understood in many ways. For the psychologist it's a creation of conscience and so it depends on one's mood. For a physicist it's one of the three fundamental quantities (the other two being mass and distance) with which anything in the Universe can be described. For a philosopher it will be other things. Neither one of them will agree with the others as to the definition.

A physicist once lost his patience in a discussion about how hard it was to define time, and he said, "It's simple! Time is what clocks measure!"

More about the Everything surrounded by Nothingness that Bigbangers believe is a perfect description of everything: you can't have something spatial surrounded by something that's non-spatial, or by nothing, since nothingness is nonexistence. They dodge the issue but they can't get rid of it by saying that anything that's not what they think is space expanding is undefined and does not exist.

It must've been the Greek thinkers in Antiquity who first made what we now call "thought experiments". One of them said: imagine that I could walk all the way over to the end of the Universe, and that I were to poke the tip of my staff through it. What would happen to it? Would it vanish?

 

[Physics-Learner]

hi daniel,

i can't figure out how anyone can't understand that we could not wait for an infinite amount of time to born ?

yes, i am throwing it on the mother universe. this is because of the qualities we have in this one. this universe had a beginning.

if we had been born in a universe with different manifestations, it might not be obvious if we were the only universe or not.

just to reiterate, i am not using the bb for any sort of assumptions. simply what is present in our universe.

 

[Physics-Learner]

i was not assuming that properties of the part defined the properties of the whole. i said it would not be too surprising to find this to be the case.

in any case, time as it has been manifested for us in this universe, means that our universe did have a beginning.

your unwillingness to accept that simply points to a bias of yours that you have yet to overcome.

 

[daniel rey m.]

"i am not using the bb for any sort of assumptions. simply what is present in our universe."

No, you say "according to the BBT matter, space and time were all created by this process", and that's your starting point, and "what is present in our Universe" is an interpretation of the raw data. Otherwise you'd be claiming that you happen to know what is present in it, as though there couldn't be more things in Heaven and Earth, Horatio, than are dreamt of in your pseudophilosophy. You are a "creationist" in the sense that you believe in something coming out of nothing, like quantum physicists, who explain certain observations by saying that particles pop up from the "vacuum" and then go back into nothingness.

"Creation" out of nothingness is a logical impossibility. What one must talk about is "manifestation". All that we see is a manifestation of things that have always existed. EX NIHILO NIHIL FIT. The laws of conservation hint at this, and brute logic decrees it.

" i was not assuming that properties of the part defined the properties of the whole. i said it would not be too surprising to find this to be the case." All right, so you're contemplating the possibility of extrapolating in such a way that features you see in accessible things will be ascribed to the entire Universe. That's either wonderfully bold or foolhardy, according to the point of view.

 

[Physics-Learner]

correct, that is what the bbt claims.

i am simply saying that the manifestation of time decries that our universe had a beginning.

again, the bbt is ONE EXPLANATION of that beginning.

the bounce universe is another explanation.

creation out of nothingness is not a logical impossibility. it is a logical impossibility in our universe.

there is nothing in this universe that one can use to make definitive statements about the super universe. which again is what you are doing when you say it is a logical impossibility. it is why the second part of that logic argument from kant is wrong.

what we do know is that this universe had a beginning. what caused it to have its beginning is beyond the black box of our universe, and therefore unattainable to us.

 

[Physics-Learner]

remember, that the cause of the creation of this universe is not part of our universe. it is not necessarily governed by any of the same laws that we are governed by in our universe.

the creation of this universe may have come from nothing in the super universe. but it may also have come from something in the super universe.

in other words, the super universe transformed something from the super universe, and made our own universe with it.

 

[Physics-Learner]

in fact, as i think about it, the bounce and the big bang are not an either or.

in the bounce cosmology, the universe expands, and then shrinks back to a singularity, and then re-expands. the big bang and the re-expansion are basically one and the same thing.

 

[Tanelorn]

I also like the water cycle analogy where all the matter and energy is eventually removed from the universe eg. in black holes. Then some random event allows the energy back into the universe in the form of an inflatron or white hole. The pinball universe game is another analogy for this.

This of course is well beyond what the LCDM model and thus completely speculative.

 

[daniel rey m.]

You keep taking for granted that the "creation" of the Universe and the singularity at the "beginning" are certainties.

Some of us believe otherwise: that 1) it was "always" there because, once again, logic (which is all we have at present) shows that nothingness is nonexistent and thus nothing can appear out of nothingness , 2) there is such a thing as "timelessness", which is a mode of existence where all that exists is simultaneous and that is not accessible to analytical thought (and this underlies point 1 since timelessness implies no beginning and no end), and 3) "singularities" like the "cosmic seed" that expanded magically (it's almost like the bean in the "Jack and the Beanstalk" story, "mutatis mutandis"[there's your homework for tomorrow!]) and "black holes" are impossibilities since infinite density and zero magnitude (the quality of being a mathematical point) at a point in space would mean infinite gravitational pull, which would absorb the entire Universe, and this is not to be observed, at least in OUR neighborhood.

Your description of the Superuniverse shows that it's your fancy (but charming) name for what others call "the Creator" or "the Supreme Being". There's even a hint of reverence in the way you talk about It, so it's surprising that you refuse to use a capital ess for It. Next time you discuss It, kindly doff your hat, if you wear one, and take your shoes off, too, so as not to soil the ground --I mean "grind the soil"-- you're treading, like Moses before the burning bramble up on Mount Horeb (thought to be present-day Mount Sinai)….

 

[Physics-Learner]

i am not sure what you mean by a capital s ? yes, time decries that the universe had a beginning. singularity is just an idea. and i am not sure that everyone even agrees on what it is ?

the super universe is indeed the creator of this universe. whether it is controlled by a being or not is simply unknown and that information simply is not available to us.

your logic fails for the same reason that the second part of the kant argument fails. it assumes that one can apply our physical laws and thought processes to something that does not necessarily follow such processes.

there is no such thing as no beginning in time within our universe. the physical manifestation that we refer to as time had a beginning. if you choose to ignore the obvious, and believe that time had no beginning, that is your choice.

you obviously have biases that keep you from accepting things about our universe.

 

[Chronos]

The big picture is muddy. We have, on one hand, a model universe that emerged from a singularity. On the other hand, we have a bouncing model universe without a singularity. We currently have no observational evidence that excludes or affirms either idea.

 

[Physics-Learner]

and we arent ever going to get any observational evidence, either - LOL.

i am not too sure it makes too much difference whether the universe shrinks down to some Planck distance, and then re-expands. or it starts at a singularity, and then either expands forever or shrinks back down to a singularity.

the current universe would still have a beginning in time.

in neither case, could we definitely know that the same sort of universe would be created again. the next one might have different laws, etc.

once again, all we can learn about is what is in our current universe.

anytime we try to venture out into what i call the super universe, it is all just speculation.

i have my own thoughts about what might occur, just like i am sure that others have.

but none of it is testable.

 

[daniel rey m.]

This matter will remain as unfinished business so long as no one ponders the possibility that both sides could be partly right and that the truth is to be found somewhere in the middle, which happens often.

Our "Universe" would be as observed --expanding space-- but just one of an indefinite number of such stretched points, and the entire thing would be like fireworks going off in endless space. Each "universe" would be merely a spark, so that there would be sparks glowing, expanding and then vanishing all around us. We'd never be able to see beyond our own. Just as in ordinary fireworks, the sparks eventually would die down, but the bursts would keep coming and the show would never end. Only a Giant in charge of the show would be able to see it in its entirety. This Giant seems to be what they call "the Multiverse". It would have to be called the Fireworks Theory.

If that's the case then the term "universe" would be inadequate for the "sparks" since there are sundry and there is only one Universe, by definition (it means "all that exists").

It would be a mistake, then, to think that, since there is definite evidence for the expansion of space all around us, infinitude must be discarded, or that, since some of that evidence is weak, then the rest of the evidence must be an erroneous interpretation of the data.

The dark-nights argument is lame because in an infinite space, supposing there would also be an infinite amount of matter in it, then, just as there would be an infinite number of stars, so, too, there would be a matching amount of dust and gas, which means that any ray of light would eventually be reflected or absorbed, but apart from that one can imagine a finite amount of matter in an infinite extension.

The same goes for the redshift argument since "tired light" or some other unknown phenomenon is still a possibility. No one knows what can happen given an infinite time interval. The usual rules might no longer be applicable when dealing with eternity and infinitude. This can be seen in physics when trying to reckon the mass of an electron. One of its two components turns out to be infinite, which is impossible, so they ignore the infinite factor, they "renormalize" and then they get on with the reckonings.
***

 

[Physics-Learner]

daniel,

i simply don't think our universe can have an infinite amount of anything.

infinite is simply an idea. it is not anything real.

how can we have both an infinite amount of space, and space that is still expanding ?

how can we have an infinite amount of anything ?

again, this only applies to our universe. i can't make any exacting statements about the multiverse, or super universe ?

infinite is not a countable number. it simply makes no sense to say there is an infinite amount of something.

 

[daniel rey m.]

Those comments show that both eternity and infinity are inherently paradoxical concepts, as I think I already said somewhere, but an infinite and eternal Uiniverse is just as inconceivable as its opposite since you can't have the Absolutely Everything impossibly placed within no context whatever except itself if it's finite. They've tried to go around this in strictly mathematical terms, by positing supposedly infinite universes that somehow wrap themselves around their own selves. There's no logical way out of the dilemma. I still don't understand how someone can be able to accept finitude but not its opposite, since both things are impossible to grasp and self-contradictory.
***

 

[Physics-Learner]

i agree that neither eternity nor infinity are possible in our universe.

but i lost you on the remainder of what you said.

finite seems like an easy concept to grasp, in our universe.

 

[daniel rey m.]

Physics-Learner,

It looks like we'll never understand each other's notions because we seem to be speaking in different languages, but here's another attempt at it.

"Our universe" is a meaningless expression when implying that there are other universes because it would mean that there's more than "our universe", whereas the definition of "universe" is "the whole system of created things". Since you believe it's possible that there are other ones then what you're really saying is that our own cosmic environment, which you refer to as "our universe", is maybe only a tiny part of what exists, and you call all that exists "the Multiverse" or "the Superuniverse". By doing that you're evading the finite-infinite dilemma because if "our universe" is only a part of what exists then obviously it must be finite, but you don't face the problem of the nature of the Multiverse, and you turn your back on it conveniently by saying you can't say anything about it. However, that our neighborhood be finite doesn't necessarily mean it has to be temporary rather than eternal. It's just that you can't accept the idea of eternal duration (or infinite extension), but you do suggest that the unknowable All (Multiverse) could be eternal and infinite.

You also claim that "finite" is something easily understood, but you're unable to explain how there can be a barrier and nothing whatever beyond it. A barrier or limit implies that there is something on both sides. You can't have a wall or whatever you want to call it between something else and nothing. Imagine yourself right now beside that barrier, and imagine that you're touching it or trying to put your arm through it. If you could do that, would your arm disappear? Would you touch a rock-hard surface?

One could call that the Cosmic Agoraphobia Syndrome. Agoraphobia is the opposite of claustrophobia, in other words, a fear of wide open spaces. One can also say there's such a thing as "infiniphobia" or "eterniphobia". Infinity and eternity are disturbing because they're inconceivable, and whatever the mind can't grasp it discards and refuses to examine.

 

[George Jones]

I have closed this thread. The Cosmology forum is for the discussion of the professional science of cosmology, not for the discussion of philosophy, personal theory, and non-mainstream ideas.