Our Finite or Infinite Universe?

[adharr]

It seems to me that there have been many attempts to provide a definition for our universe, but none of them with which I am familiar provide any logical boundaries for that all encompassing word. So, I would like to propose a new definition for the universe in which we live that while I believe does provide a meaningful "boundary", also presents what I think seem to be conceptual contradictions to our attempts to ascribe an age, size and origin of the universe.

My definition derives from the fact that within the limits of our understanding in this universe, it is impossible to achieve a temperature of absolute zero. In other words, a physical state for matter of absolutely zero energy. Expanding on that fact, this seems to apply and is true to the best of my knowledge, that there is nowhere in our universe where a temperature of absolute zero exists. Theoretically, although we can get extremely close to achieving absolute zero, we cannot get there. So, every incremental step in that direction simply leads to it being infinitely unachievable.

So, if absolute zero cannot exist within our universe, I think we can say that it could theoretically only exist OUTSIDE of our universe. Therefore, that would seem to me to imply a clearly definable "theoretical" boundary for ascribing the limits of our universe. In other words, a place beyond where any matter or energy as we know it exists.

Now, if that is the case, then just as our attempts to achieve absolute zero here on earth find the goal to be infinitely far away, then that would also seem to hold true at the boundaries of the universe. In other words, there can be no finite boundary and the universe can only be said to be infinite.

Now, if the universe can only be infinite, then it cannot be possible to determine a finite size, age or origin of the universe. After all, where do you start and where do you end? How can we define the origin as a "big bang" when we can never really establish a starting point for the oldest matter and/or energy in the universe?

 

[adrenalynn]

You're trying to reinvent thermodynamics.

The laws of thermodynamics specifically state that zero degrees Kelvin can only exist in a thermodynamic system removed from the universe.

But it certainly doesn't describe a boundary for anything, just a construct required to envision a zero-point.

I could say "pink ducks with chartreuse polkadots and an infinite number of heads can't exist in our universe. Therefore, pink ducks with chartreuse polkadots and an infinite number of heads define the edge of our universe." and it would be an equally flawed statement logically.

 

[origin]

So, if absolute zero cannot exist within our universe, I think we can say that it could theoretically only exist OUTSIDE of our universe. Therefore, that would seem to me to imply a clearly definable "theoretical" boundary for ascribing the limits of our universe. In other words, a place beyond where any matter or energy as we know it exists.

Welcome to SDC!

You are assuming there is such a thing as outside the universe. The implication is that there is space outside the universe but that it is devoid of energy and matter. The problem is that space by its very nature is full of energy and virtual particles as shown by QM and the uncertainty principle. For all intents and purposes there is no such thing as outside the uiverse.

Now, if that is the case, then just as our attempts to achieve absolute zero here on earth find the goal to be infinitely far away, then that would also seem to hold true at the boundaries of the universe. In other words, there can be no finite boundary and the universe can only be said to be infinite.

We are not trying to achieve absolute zero as far as I know since that would not be possible. There may very well be a finite boundry but you could never reach the boundry even if it was in your bathroom (as seen by an observer outside the universe - if there was such thing as an outside [my head is starting to hurt])

Now, if the universe can only be infinite, then it cannot be possible to determine a finite size, age or origin of the universe. After all, where do you start and where do you end? How can we define the origin as a "big bang" when we can never really establish a starting point for the oldest matter and/or energy in the universe?

It is actually pretty easy to calculate the age of the universe simply by measuring the recession velocities of the observable universe and then running the 'movie' in reverse.

 

[adrenalynn]

Experiments to get as close to 0K as possible are ongoing. The "coldest" observed in the wild is about 1K. 500 picoK in the lab. Femto K could be just on the horizon. Which, by the argument presented here, makes a lab in Helsinki the edge of the edge of the universe [no typo]

 

[adharr]

Hey, thanks for the posts in response and for the welcome. I'm glad to find a place to have so much fun with these discussions.

Adrenalynn, I don't quite get your statement about me trying to reinvent the laws of thermodynamics. Instead, it seems like your very next sentence fully supports my exact point that absolute zero could only exist in a thermodynamic system that is specifically NOT a part of our known universe. And yes, I do understand and agree with Origin's comment about me that there is such a thing as outside our universe, that also seems to be the whole point of seeking to define our known universe. Would that not also be true if we were talking about different "branes" of existence? I also do not see the parallel to "pink ducks with chartreuse polkadots and an infinite number of heads" not existing in our universe. I get and appreciate your point, but we don't describe the contents or building blocks of our known universe in terms of "pink ducks with chartreuse polkadots and an infinite number of heads". Instead, we define it in terms of matter and energy and seek to determine the origin, size and age of the known universe based on terms applicable to those specific ingredients. We don't have a law of "pink ducks with chartruese polkadots and an infinite number of heads" as far as I know, but we DO have laws of thermodynamics and that is exactly why it would seem logical to me to define our universe in terms of where those laws exist and where they theoretically do not exist.

And Origin, I understand about "running the movie in reverse" based on the recession velocities of the observable matter or energy "objects" or "ingredients" within the universe as you describe, but that whole "big bang" theory is hinged on there being a starting point for running the movie in reverse based simply on our capacity for those "observations" and ability to "detect" the outer limits of what we call our universe. My point is that it would seem that we could "push out" the "current state" beginning point of where we decide to hit the "rewind" button to any point we want. Simply because we are able to "observe" matter and energy to a certain point and we call that the point at which we are going to begin the "rewind" at our calculated velocities does not mean that it is in any way accurate. The only way that would truly be accurate if we were to employ that approach would be to be able to say without a doubt that there IS a boundary out there somewhere that represents the absolute furthest point away where beyond that point it is not only exactly as you say "devoid of matter and energy", but also where our known laws of thermodynamics and other laws of physics theoretically do not apply. And, where there are no "pink ducks with chartreuse polkadots and an infinite number of heads" either.

 

[adrenalynn]

Ok - so again: The edge of the edge of the universe is in a lab in Helsinki. But tomorrow it might move to Stanford, CA. Or my back pocket.

The zero crossing point is nothing but a theoretical construct to provide for a zero crossing point. It's an imaginary construct.

 

[adharr]

Okay Adrenalynn, you and I are obviously not going to see eye to eye on this. I fail to see anything imaginary about the construct of absolute zero as defined by entropy being at minimum with zero point energy and if it is a "crossing point", I will wait with baited breath to see what is on the other side. However, in any case, to me it is the bigger picture that is important. No matter whether we are able to force some state of matter or energy in a lab or not is no more relevant than our ability to create artificially made elements to add to the periodic table that are not found naturally due to the existing laws of physics as we know them. Either case would only become relevant if you are creating a new law of physics and not just pushing them to their achievable limits.

My larger point was about seeking to define the size, age and orgins or our universe by using some finite values that we have observed when by the use of those finite values, we seem to be establishing end-points defining the boundaries of our universe when, in fact, femto close or not, when you are dealing with astronomical numbers, that may not be very close at all. Yet, we have derived finite numbers for the age of our universe, the approximate size of our universe and even built the predominant theory of the "big bang" based on our calculations of red shift, the rate of expansion, cosmic background microwave radiation, etc. While all of that is certainly interesting and remarkable, all of those things seem to imply known "boundaries" to the universe based on our observations of matter and energy when we have not, to my knowledge, first established what is "included" in that term and what is not. How can you establish the age, approximate size or orgin of something when we can't or haven't even agreed on what that "something" is? Is it whereever matter and energy can be found? Is it more than that? Is it wherever our known laws of physics apply? Or is it more than that?

What is your definition and what is included and what is not? If you can't really tell me who I am or what I am and who I am not and what I am not, then doesn't it seem to be a bit getting the cart before the horse to tell me how old I am?

 

[origin]

What is included in the universe? Everthing. What is not included in the universe? Null.

 

[csmyth3025]

What is included in the universe? Everthing. What is not included in the universe? Null.

I think "Everything" just about covers it.

Chris

 

[StarRider1701]

Since our Universe is "expanding" then it must, of necessity, be finite. BUT it is SSSOOOOO VERY HUGE that we will never even come close to reaching the ever expanding edge. Which doesn't mean that we won't find a way to cut a hole in the Universe and sneak out from time to time! :lol:

 

[SpeedFreek]

Since our Universe is "expanding" then it must, of necessity, be finite.

Why do you think this? This is not the mainstream view. An expanding universe can be infinite.

http://www.astro.ucla.edu/~wright/infpoint.html

 

[adharr]

I appreciate the additional participants in this discussion and, in particular, the excellent references. There is a lot I do not understand about astrophysics and the many related theories, but I do have a fairly strong nuclear physics background and am working to continue to move forward on my learning curve in each of these areas. So, I appreciate whatever contributions any of you can make to what I consider a serious search for knowledge and understanding withut taking ourselves too seriously.

While I know that there may be some questions that we will never really be able to answer and to beat them to death may be futile, I still know we can never give up seeking to learn more. In that vein while I certainly understand the "everything" and "null" viewpoint of defining the universe, it still leaves something lacking for me. While that may, in fact, be the only answer, it leaves me with such a lack of definitiveness. To me it's kind of like saying well we really don't know how to define our universe, so we are giving-up and just not going to try and instead just saying that it can't be defined in any other way. That may be true, but it still leaves me with copping-out on attempting to give it any tangible definition. We live in a world or universe of things that we measure incessantly. While I do understand the limits of our abilty to measure things, we are certainly not letting that hold us back from applying measurements to every other aspect of the universe EXCEPT identifying what we mean by the word.

I find myself still wanting for even a commonly agreed-upon conceptual definition for how we might define our "universe", much less a truly tangible definition. It is obvious that in our everyday work in studying and explaining the universe around us that we see it in terms of things that we can measure or at least envision conceptually...ie: various forms of energy, matter, spacetime, etc. And, then there is the spiritual viewpoint. Obviously, we do not see it as a void. So, what is it and why can't we give it a better definition? What does the absence of a void mean?

 

[planetling]

SpeedFreek thank you for the link.

2 questions are presented, is the universe finite or infinite, and the question of absolute zero.

Our universe has been shown to have an "edge" and also to be expanding, however we do not have the means at this time to indicate the presence of other universe entities outside of our own. I personally believe that our observable universe is finite, lost in the perpetual clouds that make up countless other universes. And while our observable universe is finite, it is also expanding, and I believe that eventually it will be absorbed into and among the surrounding entities (other universes). I believe that cosmic occurances has and will continue to go through cycles of creating and absorbing universes for the rest of time, similar to nebula and the creation and death of stars. But for me, the questions go deeper, such as how did the multi-verse materialize, and from what? This is more mind-boggling that perceiving our own tiny universe!

While there are attempts to create absolute zero in the laboratory, it would be interesting whether we will ever know if this phenomenon actually exists in nature. Absolute zero, imo and correct me if I am wrong, would require the complete absence of matter/antimatter (we have not detected this anywhere in our own universe). Absolute zero would prevent anything from having excitement, and without excitement could not exist. On the other hand, maybe beyond our own observable universe, absolute zero could be located in pockets or voids that could potentially exist between other universes.

I am not a scholar in math or astronomy, but I do read and perform thought experiments often. Yes, these questions can cause headaches. But they are one of the few causes of headaches that are actually welcomed.

 

[xXTheOneRavenXx]

My question has always been if the universe is expanding, what is it expanding into? If the answer is nothingness then that means nothing existed prior to the creation of it. But something had to exist for the universe to be initially created. You can't make something out of nothing. Same in reverse. If the universe were contracting, then what is left in the voided space? I understand the concept of nothing existing prior to the universe because time itself having not existed. Again, the same question remains. If nothing existed prior to the creation of the universe (including time) how is it that the universe came to be? If time itself did not exist, then nothing could have formed because everything takes time to develop, change, expand, contract, etc... I find myself perplexed by the very concept of the initial stages of the universe and the current theories because of this dilema.

 

[SpeedFreek]

Our universe has been shown to have an "edge" and also to be expanding, however we do not have the means at this time to indicate the presence of other universe entities outside of our own.

Just to be clear here, the only edge we know about for our universe is the "edge" that defines our observable universe - the time light has had to travel. The whole of our universe is thought to be many magnitudes larger than our observable portion of it, and could possibly be infinite in extent.

 

[SpeedFreek]

My question has always been if the universe is expanding, what is it expanding into? If the answer is nothingness then that means nothing existed prior to the creation of it. But something had to exist for the universe to be initially created. You can't make something out of nothing. Same in reverse. If the universe were contracting, then what is left in the voided space? I understand the concept of nothing existing prior to the universe because time itself having not existed. Again, the same question remains. If nothing existed prior to the creation of the universe (including time) how is it that the universe came to be? If time itself did not exist, then nothing could have formed because everything takes time to develop, change, expand, contract, etc... I find myself perplexed by the very concept of the initial stages of the universe and the current theories because of this dilema.

The answer to what the universe expands into is not thought to be nothingness - the expansion seems to be intrinsic - general relativity does not provide us with a boundary where the universe stops and there is nothing beyond.

The concept that nothing existed before the Big-Bang simply means the Big-Bang theory says nothing about what might have existed before - it cannot say anything as there is a singularity in the way.

 

[planetling]

SpeedFreek yes, of course I was referring to the observable universe, as I have responded in my previous post. Hopefully you have understood that if you read it in its entirety

The edge as observable would be synonymous to that of our sun and planetary system, but we know that the heliosphere, interstellar boundary also makes up our solar system as a whole. However it is my belief that the expanding universe is in fact finite as I have outlined above.

 

[csmyth3025]

My question has always been if the universe is expanding, what is it expanding into? If the answer is nothingness then that means nothing existed prior to the creation of it. But something had to exist for the universe to be initially created. You can't make something out of nothing. Same in reverse. If the universe were contracting, then what is left in the voided space? I understand the concept of nothing existing prior to the universe because time itself having not existed. Again, the same question remains. If nothing existed prior to the creation of the universe (including time) how is it that the universe came to be? If time itself did not exist, then nothing could have formed because everything takes time to develop, change, expand, contract, etc... I find myself perplexed by the very concept of the initial stages of the universe and the current theories because of this dilema.

Your questions are philosophical, not scientific. SpeedFreek's reply is concise and scientific: the laws of physics as we know them can't meaningfully describe events that took place less than 10^-43 seconds after the inaugurating instant of the "Big Bang". Likewise, we can know nothing about the nature of the unverse outside of our observable universe.

If it makes you feel better to speculate about what may have existed prior to the instant of the Big Bang then take your best guess. That's not science. To say "...But something had to exist for the universe to be initially created. You can't make something out of nothing..." is your rule, not Nature's rule. If you propose something that existed prior to the instant of the Big Bang, you then raise the question: What existed prior to that "something"?

If you want to imagine something outside our observable universe, you then raise the question: What lies outside of that "something"?

In short, we define our universe as everything and we define the Big Bang as the beginning of everything. You're perplexed because you're trying to imagine what lies beyond infinity and what is less than nothing. It's unlikely that anyone will ever find the answer to these questions.

Chris

 

[planetling]

Your questions are philosophical, not scientific...

If it makes you feel better to speculate about what may have existed prior to the instant of the Big Bang then take your best guess. That's not science. To say "...But something had to exist for the universe to be initially created.

You can't make something out of nothing..." is your rule, not Nature's rule.

Chris, I may note that that is not neccessarily Nature's rule either, and that is not scientific. Because ancient man knew that the Earth was in fact flat and was put to death for believing otherwise. Experts and scholars of that time made certain of that.

If you propose something that existed prior to the instant of the Big Bang, you then raise the question: What existed prior to that "something"?

If you want to imagine something outside our observable universe, you then raise the question: What lies outside of that "something"?

In short, we define our universe as everything and we define the Big Bang as the beginning of everything. You're perplexed because you're trying to imagine what lies beyond infinity and what is less than nothing. It's unlikely that anyone will ever find the answer to these questions.

You may be right that we may never know the answer(s). However, scientific or not, and not because it makes me feel good, please do not include me into "we". I believe the big bang was one event of countless many. There may not be proof of that (yet, perhaps), but there is no proof to the contrary either.

Lately I do not understand why some people on the board are speaking down to others. While we should be corrected when in error, in lack of evidence we should feel free to express our thoughts and opinions no matter how strange they may seem. You may not like the questions or answers, but to force a point without supporting concrete proof does not advance our goal of truth.

 

[a_lost_packet_]

.... This thread doesn't make a lot of sense for being in the SS&A forum.

I prefer the boundary of the invisible, unknowable, platonic and unobtainable edge of our Universe to be a happy land where smurfs and giant space hamsters live in harmony, bartering smurf-berries and wood shavings in an economic system designed to promote peace and tranquility, for ever and ever.. and unicorns.

So, in the OP's Universe surrounded by Zero K space... How long does it take for thermal equilibrium between our Universe and <que dramatic music> The Outside? That'd be kind of an important question, wouldn't it? And, wouldn't it have been a really, really important question to ask 14.3 billion years ago, give or take 3%?

..My definition derives from the fact that within the limits of our understanding in this universe, it is impossible to achieve a temperature of absolute zero. ..

So?

How is that proof of anything? Where's this "..I do have a fairly strong nuclear physics background.." education going to show itself?

This is simple set stuff.

Set A contains everything in the Universe that is not forbidden. That means, it's everything that is possible within the Universe. Set A' contains everything that is forbidden. That's everything that is not possible in the Universe, like balanced checkbooks, a three minute line at the DMV and verifying someone's bonifides on a open forum. There ya go. I R TEH JEENIUS!

Big deal. This isn't "new." It's not some brilliant discovery. You rediscovered the wheel. A few greek guys a couple of thousand years ago would be proud of you.

 

[planetling]

To get back on topic:

You're trying to reinvent thermodynamics.

The laws of thermodynamics specifically state that zero degrees Kelvin can only exist in a thermodynamic system removed from the universe.

But can the law theoretically change if this is not the only universe. This was more of a statement

But more importantly, what effect(s) would this have and how could it be applied to something useful, other than merely knowing? Scientists are, after all, working so incredibly hard to create 0 K. Could this possibly shed light in another area of question or discovery?

 

[Beguiled]

Your logic is very good, but it breaks down in the following quote:

"Now, if that is the case, then just as our attempts to achieve absolute zero here on earth find the goal to be infinitely far away, then that would also seem to hold true at the boundaries of the universe. In other words, there can be no finite boundary and the universe can only be said to be infinite."

Because we cannot achieve it here on earth with our limited knowledge, technology, and competency doesn't mean that it is infinitely far away.

 

[captdude]

If the universe continues expanding until it experiences the "big rip" and all forms of matter are torn apart until only a state of energy exists - what would the temperature of the universe be then? Would there even be a definable universe to search for boundaries in? Roger Penrose believes this "resets" the universe to the conditions that existed BEFORE the big bang.

 

[deagleninja]

Infinite, duh....
A finite universe is literally impossible.

 

[garyegray]

I believe energy permeates throughout infinitely. The observable Universe from our vantage point, I believe, is a subset on an infinitely larger set. Also, you can find infinity within the finite, for example, you can divide any number in half, an infinite number of times - it never reaches zero and it never produces an error, you can literally keep dividing in half the result of the previous division, forever. Is the same true for energy? I tend to think it is as I do not see how you could have the smallest possible anything. We know atoms are made up of smaller forms of energy, and these smaller forms of energy are made up of even smaller forms, and so on.

Matter is made from energy and energy is composed of what Einstein called "Space/Time". We are all therefore walking and breathing "space-time".

There is no end to the Universe, only a continuation of energy in some form. Do we understand what forms this energy takes or can take? No, we do not. Some of this may be the dark energy physicists talk about, and there are probably even more exotic forms of energy that we have not begun to imagine yet.