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/sci/ - Science & Math

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5058737 No.5058737 [Reply] [Original]

Is the Universe infinite in size? Not talking about the observable universe. Presumably, every point in space has an observable universe of finite size around it. The universe is a finite age, does this entail a finite size? Or does it not make sense to think of there being an "edge" of the universe, where that point would observe nothing in the 180 degrees outwards from the edge. Both of them are hard to visualize, so /sci/ what do you say?

>> No.5058738

I remember asking one of my physics profs this very same question, and he had trouble answering it. I think because I didn't phrase it correctly.

Dude was really smart too, had degrees from harvard and cornell.

What he basically told me was that no matter where you are in the universe, it always seems as if you're in the middle, even on the very edges. What he failed to explain though was whether this is simply the universe wrapping around itself, or if there was more "universe" on the edges that was no observable by us presently in the "center".

>> No.5058746

No matter where you are in the universe you always seem from your own perspective to be in the very centre.

>> No.5058748

>>5058738
It definitely has something to do with the cosmological constant. This is what's causing the apparent paradox between finite and infinite space. Basically, space increases faster than you can observe it to, so there cannot be an edge, as it would simply observe the expansions away from itself as if it was in the center. Because of the our limit of understanding being the "observable universe", it will be near impossible to prove anything outside of this (ei multiverse etc), but the theories mostly remain open possibilities

>> No.5058750

>>5058737
The universe is everything. There is nothing beyond it. Thus it has no edge. But that does not mean it is infinite.

>> No.5058754

>>5058750
>5
How do you visualize this though. It seems that being finite implies a limit, what is the best way to think about the universe? A closed loop, an open loop, a sphere, a plane?

>> No.5058756

It's possible that it's infinite, but current evidence suggests otherwise.

>> No.5058757

>>5058748
That's false

>> No.5058758

>>5058754
I don't visualize it. There is no place to stand outside the universe. And if there is no edge to the universe there is nothing to see from within. What's there to visualize?

>> No.5058759

>>5058756
I think that the current view of the big rip or big freeze, seems to imply that the universe is finite and will expand TO infinite size, therefore it is not detectable to anyone inside the universe during the transition that it is one or the other

>> No.5058765

the human brain is simply not wired to visualize things like that. it makes no sense to apply any analogy to the universe, it is how it is and our limited hardware will scarcely be able to conceive of its true nature

>> No.5058767

>>5058738
It's like a video game where if you cross the edges of the map you appear on the opposite side, except in 3d.

>> No.5058769

>>5058767
Nah, the universe is really a toroidal helix

>> No.5058771

Even if the universe is finite why lays just beyond the last star? Empty vacuum? Shouldn't the empty vacuum count as something? Does it just continue on forever? An eternity of empty vacuum, waiting for matter to expand into it?

>> No.5058777

>>5058771
But you are still trying to imagine that vacuum as space. Infact, I believe you'll find, you cannot imagine something thats not space. It's space expanding beyond itself. not space expanding into space. An "empty vacuum" still implies a sense of space. You just have to accept that you cannot know what 'beyond space' looks like

>> No.5058784

>>5058754
I visualize it as something similar to a mobius strip, but it can get bigger, having a finite size but no edges and maximum size.

I don't think of it as a bubble where there's something outside it, but more like you're traveling along the outside of sphere, like how if you walked around the Earth, you'd end up back where you started, but not "wrapping around to the other side" or anything.

Although going back to the mobius strip comparison, I like to think that there's another "side" opposite your position you can't interact with unless you're over there.

>> No.5058786

Wow, what a bunch of wankers. There is no evidence that the universe wraps back around itself, why must you enforce this obsession?

If you want to blow your little 420 minds try and comprehend a dimensionless vacuum.

>> No.5058788

Whattabout that whole multiverse idea?
Not the parallel universe one, but the one where if you go far enough you'll come across another one.
http://en.wikipedia.org/wiki/Multiverse#Level_I:_Beyond_our_cosmological_horizon
Woulnd't this require an infinite universe?

>> No.5058793

>>5058786
Why shouldn't the universe be sphere shaped? Even if it weren't possible to go to any point, you should at least be able to hit the edge of the ball and move along it. Why would it be infinite or something? And you can't not have dimensions, even if nothing exists there. Unless you're, like, a singularity.

>> No.5058857

>>5058793
if so, what does a singularity on the edge of the universe entail? a dip on the surface of the sphere?

cool

>> No.5058899

You do realize the universe may be curved the other way.. hyperbolic?

>> No.5059924

I thought the universe was flat since the net energy was 0.

>> No.5059938

>>5059924
It's very close to flat (on the scale of, say, our galaxy cluster) but very large scales it's curved.

>> No.5059941

its infinite and expanding, there was a brilliant pop sci program on the bbc called something like "mapping the universe" explaining it. perhaps its on iplayer

>> No.5060085

If the multiverse theory is true, what would be the term for whatever space is encompassing all the universes?

>> No.5060101

>>5058737
>Is the Universe infinite in size?

We don't know. Which is pretty remarkable in itself - we haven't yet seen anything to rule out an infinite universe.

Not talking about the observable universe. Presumably, every point in space has an observable universe of finite size around it.

True.

The universe is a finite age, does this entail a finite size?

No. One actually has nothing to do with the other.

>Or does it not make sense to think of there being an "edge" of the universe, where that point would observe nothing in the 180 degrees outwards from the edge.

Right. That's definitely NOT the case. If the universe is finite, it's definitely not just like a regular 3D shape like that. It wouldn't have an "edge." You need curved geometries to describe any real possibility.