# Universe is infinite only in a theoretical sense?

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Good morning. I had an interesting thought while reading one of my old posts. This sounds a lot like a law but I just wanted to post this here to see if there any flaws in my statement.

The universe is finite so long as no one particle or object passes the furthest former borders of the universe as defined by the two farthest outlying particles or objects from that particle or object, these three particles or objects describing a plane, with these three particles or objects being points describing this plane. In this fashion the size of the universe is relative to and described by it's own matter and energy, also in this fashion the universe is infinite, but only in a theoretical sense, as anything passing the farthest outlying point would become the new farthest outlying point. Also in this fashion the universe is homogenous and isotrophic, and it's expansion is even as governed by the three points. Finally the existence of these three points seperately defines time as a differential between them.

Please point out any elbow bumping with or complete disregard of any laws in my statement so that I can remove the part that is not in accordance with that law.

Thanks, Dan.

Edited by DanTrentfield
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What do you mean by "borders of the universe"? In current models there is no such border.

Also, how do two points define a plane? I thought you needed three points to define a plane.

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The universe is finite so long as no one particle or object passes the furthest former borders of the universe as defined by the farthest outlying particle or object from that particle or object,

The universe can be finite and unbounded I.e. no edge. Ask yourself: where is the furthest point on the surface of a sphere? This is an example of an unbounded but finite plane. Apply that 2D example to 3D. You seem to be making the common mistake that the cosmic expansion is radial with a leading edge. The universe expands equally everywhere where the gravitational force does not overwhelm the expansion; any objects or group of objects, about, more than 200m light years apart. Anything less than that, then gravity is too strong.

Edited by StringJunky
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The universe can be finite and unbounded I.e. no edge. Ask yourself: where is the furthest point on the surface of a sphere? This is an example of an unbounded but finite area. Apply that 2D example to 3D. You seem to be making the common mistake that the cosmic expansion is radial with a leading edge. The universe expands equally everywhere where the gravitational does not overwhelm the expansion; Any objects or group of objects, about, more than 200m light years apart. Anything less and gravity is too strong.

I did? I thought I covered it with "even expansion". Besides that how does this fare?

What do you mean by "borders of the universe"? In current models there is no such border.

Also, how do two points define a plane? I thought you needed three points to define a plane.

you're correct. It's been a while since I've taken geometry.
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And what does "hexagonal axes" mean? And wouldn't that require 6 points (or more)?

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I did? I thought I covered it with "even expansion". Besides that how does this fare? you're correct. It's been a while since I've taken geometry.

Border as defined by the part of the universe without matter or energy that technically doesn't exist yet.

And what does "hexagonal axes" mean? And wouldn't that require 6 points (or more)?

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Border as defined by the part of the universe without matter or energy that technically doesn't exist yet.

There is no such part of the universe. The universe is and always has been homogeneously full of matter (on large enough scales).

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Border as defined by the part of the universe without matter or energy that technically doesn't exist yet.

It's a hard concept, a universe that contains everything, has no borders, but expands nonetheless. It's very difficult to think of the word "expand" and not follow it with "into".

I like the infinite Grand Hotel analogy. In a hotel with an infinite amount of rooms, and an infinite amount of guests, when a new guest checks in, a new room isn't created in previously unexisting space. If each guest moves from his current room (n) to the next room down (n+1), and so on infinitely, then the new guests get room 1, and the hotel can expand infinitely. Expansion without space, matter or energy that technically doesn't exist yet.

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There is no such part of the universe. The universe is and always has been homogeneously full of matter (on large enough scales).

That's why it technically wouldn't "exist" It just isn't there yet, but it will be when expansion reaches that point.

It's a hard concept, a universe that contains everything, has no borders, but expands nonetheless. It's very difficult to think of the word "expand" and not follow it with "into".

I like the infinite Grand Hotel analogy. In a hotel with an infinite amount of rooms, and an infinite amount of guests, when a new guest checks in, a new room isn't created in previously unexisting space. If each guest moves from his current room (n) to the next room down (n+1), and so on infinitely, then the new guests get room 1, and the hotel can expand infinitely. Expansion without space, matter or energy that technically doesn't exist yet.

That is an interesting analogy. Well.... it's not that hard in reality, for example, I have a plane composed of three points, and a point on the plane. They are titled A B C and D for the point on the plane. If D moves beyond A then D becomes the new A but still remains D. A becomes the new D, but still remains A, and is now on the plane instead of defining the theoretical limit of it.

And Strange, if we're going with your statement, wouldn't that mean that since the universe is homogeneously full of matter, that I'm on to something?

Edited by DanTrentfield
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You're still talking about the expansions as if the universe is pushing outward. It is not. The expansion is taking places between points within the universe. There is no edge. Matter isn't moving into previously unoccupied space. Space isn't even expanding outward past some current limit at the edge of the universe.

The expansion is happening between us and other things we can see within the universe. Not at it's fringes. We don't even know if the universe has fringes and it's unlikely we'll ever be able to see them if it does.

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That's why it technically wouldn't "exist" It just isn't there yet, but it will be when expansion reaches that point.

There is no such point. The universe is all there is.

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Are you in a strange way thinking of the notion of the Observable Universe? This is always finite, but as for the whole Universe we just don't know. The global shape (the topology) of 'everything' is just not known, nor do our theories of gravity say much about this.

Edited by ajb
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I believe I've been going about this the entirely wrong way. Scratch the planar approach; Lets say the universe is like a torus, with it's expansion being equal both on the X and the Y axis. Now going from what both Phi and Delta have explained this torus is not expanding relative to itself, but is expanding relative to us, and at such a rate that we could never reach the edge of it, but there are hypothetical edges. With the type of expansion being exactly the same kind as the one explained by Phi's "Infinite Grand Hotel". So with this new representation we have a universe that is infinite, but only theoretically, with hypothetical edges beyond which there is nothing, Now to account for the possibility of us going around the vertical or horizontal circumference of the torus I ask you to remember that this model would be expanding far faster than we could ever travel, relative to us that is. The torus approach would allow for our three dimensions, and would comply with the statements made thus far.

Are you in a strange way thinking of the notion of the Observable Universe? This is always finite, but as for the whole Universe we just don't know. The global shape (the topology) of 'everything' is just not known, nor do our theories of gravity say much about this.

Yes, I am in a strange way thinking of the observable universe. I'm trying to disprove the notion that the universe is an absolute infinity in terms of size, even relative to itself, because a universe being infinite relative to itself does not make much sense, as it wouldn't be infinite relative to itself without it being ∞.

There is no such point. The universe is all there is.

Edited by DanTrentfield
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I believe I've been going about this the entirely wrong way. Scratch the planar approach; Lets say the universe is like a torus, with it's expansion being equal both on the X and the Y axis. Now going from what both Phi and Delta have explained this torus is not expanding relative to itself, but is expanding relative to us, and at such a rate that we could never reach the edge of it, but there are hypothetical edges. With the type of expansion being exactly the same kind as the one explained by Phi's "Infinite Grand Hotel". So with this new representation we have a universe that is infinite, but only theoretically, with hypothetical edges beyond which there is nothing, Now to account for the possibility of us going around the vertical circumference of the torus I ask you to remember that this model would be expanding far faster than we could ever travel, relative to us that is. The torus approach would allow for our three dimensions, and would comply with the statements made thus far.

Yes, I am in a strange way thinking of the observable universe. I'm trying to disprove the notion that the universe is an absolute infinity in terms of size, even relative to itself, because a universe being infinite relative to itself does not make much sense, as it wouldn't be infinite relative to itself without it being ∞.

It might help if you resist thinking of the universe as a discrete object inside a volume i.e. from the outside of the universe because you can't seem to visualise that conceptual space around the universe as merely an aid to objectifying it; you see it as something real. The absolute inescapable fact is that the observer is part of, and within, the universe. The notion of the universe having an overall shape, volume and size is moot and unknowable. When you see representations of the shape of it in science articles they are describing its spatial topology or behaviour/structure of spacetime over a very large sample of the universe.

Edited by StringJunky
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It might help if you resist thinking of the universe as a discrete object inside a volume i.e. from the outside of the universe because you can't seem to visualise that conceptual space around the universe as merely an aid to objectifying it; you see it as something real. The absolute inescapable fact is that the observer is part of, and within, the universe. The notion of the universe having an overall shape, volume and size is moot and unknowable. When you see representations of the shape of it in science articles they are describing its spatial topology or behaviour/structure of spacetime over a very large sample of the universe.

Okay, but let's say that somehow we were able to observe the universe from the non-existent outside of it using say.... "Magic" Would my model be off then? And since the universe is theoretically contained within itself as Delta1212 explained, it must then have a definable hypothetical edge, unreachable by us, but an edge none the less, otherwise we end up once again with a ∞ problem. Unless that's how the universe can be defined in size.

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Okay, but let's say that somehow we were able to observe the universe from the non-existent outside of it using say.... "Magic" Would my model be off then? And since the universe is theoretically contained within itself as Delta1212 explained, it must then have a definable hypothetical edge, unreachable by us, but an edge none the less, otherwise we end up once again with a ∞ problem. Unless that's how the universe can be defined in size.

I don't know. Perhaps one of the more knowledgeable will say something about it.

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There does not have to be an edge. There may be an edge. Or the universe may be infinite. Or the universe may be finite but unbounded. (As is the surface of the Earth, where you can travel infinitely in any direction without reaching the edge of the surface of the Earth, and yet the Earth's surface is not infinitely large).

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Yes, I am in a strange way thinking of the observable universe. I'm trying to disprove the notion that the universe is an absolute infinity in terms of size, even relative to itself, because a universe being infinite relative to itself does not make much sense, as it wouldn't be infinite relative to itself without it being ∞

I doubt you can really prove much here. People are looking for signals for a compact topology, for instance we may see repetitions of galaxies in the sky. However, right now we have no indications of the topology of the Universe. So right now all anyone can say is 'we don't know'.

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• 2 weeks later...

I doubt you can really prove much here. People are looking for signals for a compact topology, for instance we may see repetitions of galaxies in the sky. However, right now we have no indications of the topology of the Universe. So right now all anyone can say is 'we don't know'.

You are indeed correct about that. After all we cannot assume something we know nothing about. That nothing being the universe's nature of infinity. Thank you all for your insight into universal expansion, it helped me reform my concepts on it much. I must ask though, would it be theoretically possible to devise an experiment to gauge whether the universe is infinite or finite? Please don't say that it is beyond our understanding, it can be beyond our current understanding, but never beyond understanding, as the impossibilities of yesterday are part of common life today, demonstrating perfectly the adaptable nature of humanity.
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You are indeed correct about that. After all we cannot assume something we know nothing about. That nothing being the universe's nature of infinity. Thank you all for your insight into universal expansion, it helped me reform my concepts on it much. I must ask though, would it be theoretically possible to devise an experiment to gauge whether the universe is infinite or finite? Please don't say that it is beyond our understanding, it can be beyond our current understanding, but never beyond understanding, as the impossibilities of yesterday are part of common life today, demonstrating perfectly the adaptable nature of humanity.

I don't think it has as much to do with understanding as it does with definition. No matter what you do to test if something is infinite or not, you actually have to wait for it to stop or continue forever. You could say it was finite when it stops, but how could you ever say it's infinite without waiting around forever to see?

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Well something certainly can be beyond understanding under any circumstances. It's just not always easy to tell whether something is beyond current understanding or beyond ever being understand regardless of what we do.

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Well something certainly can be beyond understanding under any circumstances. It's just not always easy to tell whether something is beyond current understanding or beyond ever being understand regardless of what we do.

Exactly my point. "Impossible is only impossible in the short term, there is a way to achieve anything, but it is impossible to us in the current because we have no knowledge of the existence of that way." -Anonymous Edited by DanTrentfield
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On the other hand, some things might just be impossible. In any timescale.

I think Anonymous is being hopelessly naive.

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I think Anonymous is being hopelessly naive.

And infinitely imaginary.

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Wouldn't something have to be equally infinite on a deceasing scale as well as an increasing one to actually be infinite?

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