Forget Flat Earth Theory, now we have Flat Universe Theory!

[theVOID]

Net energy = 0

God is a vacuum

[TheDarkestOfAngels]

The surface of a sphere is infinite. You can keep going on it and never reach an end.

The surface of a sphere is not infinate in any respect to volume or space.

It is possible to have different degrees of infinity. Imagine two infinities. One is an ordered collection of all real numbers (..... -1.000000, -0.999999999, ....etc) from negative infinity to positive infinity, the other an ordered collection of all integers (... -1, 0, 1.....) from negative infinity to positive infinity. The infinite number of all real numbers is definitely larger than the infinite number of all integers. You can prove this to yourself by seeing that you can map every one of the infinite number of integers onto a unique real number, ( 1 to 1.00000, 2 to 2.00000, etc) and you still have an infinite number of unmapped real numbers left (0.9999999, 1.0000001, 1.0000002, etc)

You are indeed correct that mathmatical infinities are quite possible.
This cannot and never does apply to reality. You cannot have an infinate amount of space in a box just because you can keep moving indefinately in one direction due to being able to continuously slow down enough to never actually impact one side of the box.
This is a major stretch.

But you can make the smaller infinity that is the count of integers larger by also including a count of all numbers divisible by 0.5, So something infinite can still expand (......-1, -0.5, 0, 0.5, 1......) This is what is happening when infinite universe expands.

You certainly can - mathmatially - it just doesn't apply to reality due to a number of huge problems it can create.
For example, a 'smaller infinity' expanding into a 'larger infinity' is problematic because they 're both infinate in space and volume and therefore must expand into the larger universe using other sets of infinities - the 'dark' energy responsible for the expansion of the universe would have to be infinate as well, for example.
... eh. The short of it is that an infinity in one dimension essentilaly requires infinities in others that would ultimately result in a reality that we know of that couldn't exist.

The universe can be infinite and still expand because just like expansion of the infinite count of integers, you can take each discreet subpart of the infinite universe, say a 1 light year length analogous to say part of count of integers between 2 and 3, and expand it to 2 light years, analogous to inserting 2.5 between 2 and 3.

So the universe can be infinite, and still expand. It doesn't expand into anything, each part of it just expands.

I don't think it can be without serious problems of a mathmatically-relevant system that's supposed to correspond to reality. Every infinity that I've seen apply to reality has had serious problems in actually making a model that's consistent with reality-based predictions - which is the main reason why all of the physics that I know slightly better behind the mathmatical models of the universe all list it as finite in size and only go up so far in describing reality, with possibilities and theories that go steps above. I've never seen a model of any kind that's relevant today that has an infinity in any respect that doesn't cause serious problems in generating an accurate model of reality.

[theVOID]

The surface of a sphere is infinite. You can keep going on it and never reach an end.

The surface of a sphere is not infinate in any respect to volume or space.

Neither is a Circle in that respect. PI breaks down at plank length. Though the boundary is still infinitely traversable even though it's finite in space and volume.

You are indeed correct that mathmatical infinities are quite possible. This cannot and never does apply to reality.

That sounds like a positive claim to me. I'm not in any sense prepared to rule out the possibility of an infinite space with finite regions, not aver reading Alexander Vilenkin's work. They seem mysterious, but when you have a feedback loop and vacuum energy there quite literally appears to be an infinite number of finite sets (potential configurations).

You cannot have an infinate amount of space in a box just because you can keep moving indefinately in one direction due to being able to continuously slow down enough to never actually impact one side of the box.
This is a major stretch.

That's a false analogy, just because x is finite in space does not mean that it is finitely traversable.

A curved universe would be the same, you look far enough in one direction and you see the back of your head, even though this universe would be spatially finite.

[orogenicman]

The surface of a sphere is not infinate (sic) in any respect to volume or space.

This is true. However, the surface of a sphere is unbounded in that if you could walk on that surface, you could walk essentially forever and not find a beginning or end. Similarly, I've heard the universe described as finite but unbounded. That's my two cents' worth.

[TheDarkestOfAngels]

Neither is a Circle in that respect. PI breaks down at plank length. Though the boundary is still infinitely traversable even though it's finite in space and volume.

So is walking in place in a circle. You can keep going forever, but the space you're transversing is still finite.

That sounds like a positive claim to me. I'm not in any sense prepared to rule out the possibility of an infinite space with finite regions, not aver reading Alexander Vilenkin's work. They seem mysterious, but when you have a feedback loop and vacuum energy there quite literally appears to be an infinite number of finite sets (potential configurations).

Neither am I of the possibility of infinate space with finite regions - I just don't think it's likely. As I'm trying to convey from my initial post is that I'm trying to cite this as my own conclusions based on what is essentially incomplete evidence.
I think that that is where the evidence we have leads, but we really can't say anything about what's beyond our 13.7 billion light-year radius vision of the universe and some of the mathmatical models based on the physics that we understand of the universe.
I personally don't like the idea that anything is infinate because most of the people I've read about who do the science behind the kind of universe in which we live on that scale, adding infinities in any sense seems to have always been problematic because it creates a systematic problem in which every connecting portion of reality to that infinity must also be infinate.
Still, the universe could always be much wierder and do things no one could have imagined before, so who knows, really?

That's a false analogy, just because x is finite in space does not mean that it is finitely traversable.

I wasn't posing an arguement that the universe wasn't infinately transversable.
You can infinately transverse just about anything if you have infinate time and space to move.

A curved universe would be the same, you look far enough in one direction and you see the back of your head, even though this universe would be spatially finite.

Indeed - but the universe is either not curved or it's not curved enough to be detectable with current methods. To my knowledge, an experiment was done in an attempt to see if this was the case by shooting two probes in different directions and seeing if the total number of degrees between them was equal to or greater than 180 degrees.
If equal, then the universe is flat but if greater, then the universe is curved. The experiment proved the former. Alternatively, it might also be a situation where the universe is so huge that the curve escapes detection even by our high precision lasers, but the evidence that we have points to it being flat.

This is true. However, the surface of a sphere is unbounded in that if you could walk on that surface, you could walk essentially forever and not find a beginning or end. Similarly, I've heard the universe described as finite but unbounded. That's my two cents' worth.

Right. What I'm arguing against is that the universe is infinate in the sense that you can keep going in one direction forever and never reach your previous position if the space you transverse is always flat and never curves back on itself - such as if the universe were spherical in its dimensions like the earth is spherical.

[theVOID]

Neither is a Circle in that respect. PI breaks down at plank length. Though the boundary is still infinitely traversable even though it's finite in space and volume.

So is walking in place in a circle. You can keep going forever, but the space you're transversing is still finite.

Yeah. Infinitely traversable =/= infinitely spatial. Just like you can hypothetically cut a circle with intersecting lines an infinite number of times while the spatial dimensions remain constant and finite.

Just because an object has the one set of finite properties does not mean that it necessarily has no infinite properties.

Neither am I of the possibility of infinate space with finite regions - I just don't think it's likely. As I'm trying to convey from my initial post is that I'm trying to cite this as my own conclusions based on what is essentially incomplete evidence.

We already know such things exist via the Casimir effect, if you have two charged metal plates in a vacuum the number of potential vacuum fluctuations between the plates is infinite, but the number of potential vacuum fluctuations outside of the plates is greater (because of a larger spatial region thus more vacuum potential), this force of competing infinites creates a type of field that is stronger outside the plates and thus forces them together despite no material influence.

If you can think of an explanation for these observations that doesn't depend on competing sets of infinites then I would love to hear it, unfortunately it will still be the second best explanation as the Casimir effect was predicted as a result of this exact train of thought.

I think that that is where the evidence we have leads, but we really can't say anything about what's beyond our 13.7 billion light-year radius vision of the universe and some of the mathmatical models based on the physics that we understand of the universe.

Not true, we know that regions of infinite density likely exist through our robust models like relativity, we have infinites with the Casimir effect, we have the probability amplitudes of quantum events with self-interference leading to another infinite set of possible combinations... Infinites are suggested by observation quite frequently.

I personally don't like the idea that anything is infinate because most of the people I've read about who do the science behind the kind of universe in which we live on that scale, adding infinities in any sense seems to have always been problematic because it creates a systematic problem in which every connecting portion of reality to that infinity must also be infinate.
Still, the universe could always be much wierder and do things no one could have imagined before, so who knows, really?

Again see Alexander Vilenkin

And the idea that one set of infinites leads to every related phenomenon being infinite is plain false, take the sphere again, it's infinitely traversable but the room in which it is located isn't.

And I really don't see how you can dislike the idea of infinites, let alone use that as a reason to conclude that they aren't applicable. It's incredulity plain and simple.

That's a false analogy, just because x is finite in space does not mean that it is finitely traversable.

I wasn't posing an arguement that the universe wasn't infinately transversable.
You can infinately transverse just about anything if you have infinate time and space to move.

If you have infinite space then you necessarily have infinite traversability, but infinite space is not necessary, all you need is a closed loop of some kind.

A curved universe would be the same, you look far enough in one direction and you see the back of your head, even though this universe would be spatially finite.

Indeed - but the universe is either not curved or it's not curved enough to be detectable with current methods. To my knowledge, an experiment was done in an attempt to see if this was the case by shooting two probes in different directions and seeing if the total number of degrees between them was equal to or greater than 180 degrees.

Sure, I don't think the universe is curved, the flat universe idea makes more sense. I'm not sure that any conclusions at this point is justified.

Anyway, the space-probe experiment is really inconclusive, the curvature could be so tiny over that distance that it's immeasurable, that doesn't rule out curvature. It's like walking .05 of a centimetre and concluding the earth is flat.

[TheDarkestOfAngels]

Yeah. Infinitely traversable =/= infinitely spatial. Just like you can hypothetically cut a circle with intersecting lines an infinite number of times while the spatial dimensions remain constant and finite.

Just because an object has the one set of finite properties does not mean that it necessarily has no infinite properties.

Right - I just don't consider 'transversibility' to be a property of space itself in the context of this arguement.

We already know such things exist via the Casimir effect, if you have two charged metal plates in a vacuum the number of potential vacuum fluctuations between the plates is infinite, but the number of potential vacuum fluctuations outside of the plates is greater (because of a larger spatial region thus more vacuum potential), this force of competing infinites creates a type of field that is stronger outside the plates and thus forces them together despite no material influence.

If you can think of an explanation for these observations that doesn't depend on competing sets of infinites then I would love to hear it, unfortunately it will still be the second best explanation as the Casimir effect was predicted as a result of this exact train of thought.

I'm familiar with the casmir effect, but I don't see how this is an exampe of competing infinities.
There is energy in a vacuum of space and that energy fluctuates over what I can only assume is an enormous number of variables - but not infinite.
This has to go with one of the theories as to how a total vacuum can produce a singularity that can explode into a universe such as ours. The idea is that if these fluctations were like a deck of cards then hitting the genesis button is like shuffling every moment of every day with a virtually endless amount of time available - one day you can shuffle and produce a perfectly ordered deck of cards. The chances of this happening is so rare that only the enormity of the expanse of time in the previous universe's vacuum can have a chance of spawning a new singularity that can itself spawn a big bang that produces a universe like ours.
This cannot be done with an infinately large deck of cards by the very nature of an infinity - even if time were also infinte. As such, I have my doubts as to whether the casmir effect, even if described under terms of infinities, is actually a result of competing energy infinities in the vacuum and not simply two competing finite energies.

Not true, we know that regions of infinite density likely exist through our robust models like relativity, we have infinites with the Casimir effect, we have the probability amplitudes of quantum events with self-interference leading to another infinite set of possible combinations... Infinites are suggested by observation quite frequently.

People seem to say things like that, but my understanding of physics in this regard is that physicists often use 'infinite' to also mean 'very large.'
For example, people say that the core of a black hole is infinate in density and there's a whole host of theories about what goes on in there because what we know about physics gets stretched either to the limits or beyond the limits of our understanding about these things. In essence, a black hole core is essentially infinate if not functionally infinate and I've seen instances of this apply in other areas as well.
Further, I don't think the core of any black hole has infinate density because that requires infinate mass crushed into a finite point when that is clearly impossible. There is also the issue that the core of a black hole under natural conditions is impossible to observe using current methods and this is one of those things that we don't really know a lot about.

Again see Alexander Vilenkin

I'll keep that name in mind during my next visit to the library this saturday.

And the idea that one set of infinites leads to every related phenomenon being infinite is plain false, take the sphere again, it's infinitely traversable but the room in which it is located isn't.

And I really don't see how you can dislike the idea of infinites, let alone use that as a reason to conclude that they aren't applicable. It's incredulity plain and simple.

... not necessarily all of them, but I don't view the sphere-infinately transversible example as interrelated properties because under the right conditions, any space can be infinately transversible.
The kind of thing I'm thinking of is like the old static universe arguement before the big bang started having evidence getting piled in its favor. One of the problems with it is that no matter which direction you went from any point, you would always - always - end at the surface of a star.
For this arguement, I've been assuming that we're talking about a finite region in an infinate vacuum - which is to say that the big bang and all the matter and energy that formed from it exists in a finite reigion of infinate space.
The problem I have with this is that the vacuum energy outside of this religion is infinate because the space around this region is infinate. There is also an issue with the random fluctuations because if a particular pattern or fluctuation can form a universe, then the property of this infinate fluctuation and infinate size of the universe means that the possibility of a universe forming anywhere at any time is always one. You see where I'm going?

This doesn't preclude the possibility that there are other variables at play that may limit this from happening in this manner - even if I'm utterly wrong, but I think the more likely scenario is that neither the fluctuations nor the void (if there is one) beyond our obsevation on earth are anything but finite in scope.

If you have infinite space then you necessarily have infinite traversability, but infinite space is not necessary, all you need is a closed loop of some kind.

Right - I don't disagree with that but I'm trying to limit the arguement to the transversible space and not the ability to transverse it. I don't see them as one being a property of the other. Like I don't see humans as a property of the earth itself, despite the interrelation.

Sure, I don't think the universe is curved, the flat universe idea makes more sense. I'm not sure that any conclusions at this point is justified.

Anyway, the space-probe experiment is really inconclusive, the curvature could be so tiny over that distance that it's immeasurable, that doesn't rule out curvature. It's like walking .05 of a centimetre and concluding the earth is flat.

I wouldn't rule that out - but I also wouldn't entirely rule out the results. Like all good scientific studies, it's merely a piece of a much larger and more interesting puzzle.

[Ashendant]

I never thought that space/time expanded with the big bang, i always thought what expanded was matter/energy with the big bang, doesn't matter curve space/time, or is that it the space/time began to expand because matter expanded, or was the curvature of space/time that expanded with matter...

i'm seriously confused right now

The universe is obviously not flat, we clearly live in a three-dimensional space, and for the universe to be flat we would need to live in a two-dimensional space

[Lethe]

The universe is obviously not flat, we clearly live in a three-dimensional space, and for the universe to be flat we would need to live in a two-dimensional space.

It's referring to the curvature of the universe. Basically, the angles of a triangle will always add up to 180 degrees, as opposed to more than 180 degrees (closed/spherical), or less than 180 degrees (open).



Though now that I'm looking in to three dimensional geometry... ow, my head hurts.

[Anomalocaris]

I never thought that space/time expanded with the big bang, i always thought what expanded was matter/energy with the big bang, doesn't matter curve space/time, or is that it the space/time began to expand because matter expanded, or was the curvature of space/time that expanded with matter...

i'm seriously confused right now

The universe is obviously not flat, we clearly live in a three-dimensional space, and for the universe to be flat we would need to live in a two-dimensional space

No, it's the other way around. Matter expanded because space expanded. One could imagine the distant galaxies that are rushing away from us at near the speed of light as in fact sitting still in space, but space itself is stretching under the combined influence of kinetic energy, gravitational potential energy, and newly discovered dark energy and carrying it away from us.

Universe is not flat and has at least 3 spacial dimensions, When people say universe has a certain shape, they mean how space is stretching would determine whether certain behaviors of objects in space would be best described by a geometry problem solved on one of the following: a plane (flat), on a sphere (closed) or on a hyperbolic surface (open). They don't mean space has any shape corresponding to normal human notion of shape.