Space - is it infinite?

Dark_Angel · 26 Mar 2008 at 16:25

Some people say it isn't, but it is growing at a speed faster than light, others say it is finite, and other people just kinda shrug.

Please bare in mind, I am *not* talking about the universe, in other words the space where there is "stars and planets" I am talking about the literally black empty cold space.

I heard that currently they have a model at the moment where only 4 percent or so of the universe is made with atoms, everything else is made of Dark Matter and Dark Energy (and by made, I mean the majoriy of the mass comprises of) - kind of cool really

platypus · 26 Mar 2008 at 16:25

Space, is.

Darkwave · 26 Mar 2008 at 16:26

I might sound like an idiot, but if you're not talking about the universe then what are you talking about?

Dark_Angel · 26 Mar 2008 at 16:30

Ulfhedjinn said:
I might sound like an idiot, but if you're not talking about the universe then what are you talking about?

I basically mean charging past ALL of the stars and everything else. Just how you go past our galaxy (the milky way) and you keep going to find another, then eventually you go out of our galaxy.

Are we completely sure space is infinite, in other words, if you travelled at the speed of light for 1 trillion years (ok couldn't happen but still) would we be thinking "ok, this is a long way back now"... I have heard some people say that space is curved, so at some point you come back to the start (kind of like a large circle like earth is)

Sorry for my ignorance, I know bits about space, like black holes, stars and stuff but not much about the theories behind this kinda thing

platypus · 26 Mar 2008 at 16:31

Dark_Angel said:
Are we completely sure space is infinite, in other words, if you travelled at the speed of light for 1 trillion years (ok couldn't happen but still) would we be thinking "ok, this is a long way back now"... I have heard some people say that space is curved, so at some point you come back to the start (kind of like a large circle like earth is)

But if you travelled somewhere at the speed of light, you'd get there before you got there, so would never need to go there because you'd already be there. In that regard, space is infinite.

Glaucus · 26 Mar 2008 at 16:32

It all depends if you talk about space as the universe. Or the nothingness it's growing into.

Spektor · 26 Mar 2008 at 16:32

no, we live in a finite universe so nothing can be infinite.

Solari · 26 Mar 2008 at 16:32

*head explodes*

I wonder about this a lot when I'm bored.

platypus · 26 Mar 2008 at 16:33

Spektor said:
no, we live in a finite universe so nothing can be infinite.

Why does a finite universe negate the possibility of there being an infinite multiverse?

gord · 26 Mar 2008 at 16:33

Ulfhedjinn said:
I might sound like an idiot, but if you're not talking about the universe then what are you talking about?

The garage.. had a clear out the other day.. and there is SOOoo much space you wont believe!

Dont think its infinite though.. will go check.. wont be back till.. well.. ever if its infinite.

Darkwave · 26 Mar 2008 at 16:35

Dark_Angel said:
I basically mean charging past ALL of the stars and everything else. Just how you go past our galaxy (the milky way) and you keep going to find another, then eventually you go out of our galaxy.

I think I know what you mean now, but I'm not entirely sure.

If you travel out into space in a straight line eventually you will reach the edge of our galaxy and leave it. You will have an immense empty space after that but eventually you are going to enter the star field of another galaxy, and this will probably go on forever until you reach the edge of the universe.

By my reckoning that means that space isn't infinite, I mean the universe is expanding after all.

I won't get into the "edge of the universe" or curved universe stuff as I have really don't know anything about that. Not through lack of trying I might add, just because for some reason I can't get my head around it.

Dark_Angel · 26 Mar 2008 at 16:36

AcidHell2 said:
It all depends if you talk about space as the universe. Or the nothingness it's growing into.

Well, I had read that the universe is expanding, but no, I meant literally the vast open blackness of space.

I mean, what the hell happens if there is an edge and you reach and and take the plundge off? do you suddenly appear in a different universe

/adds petrol. Perhaps this dark matter and energy is just parallel universes

Spektor · 26 Mar 2008 at 16:36

platypus said:
Why does a finite universe negate the possibility of there being an infinite multiverse?

It doesn't, a universe is not a multiverse, our particular bubble of space-time is finite and will cease to be -- and who knows whether the branes of existance we cling to are infinite, but beings of a 3D existance can't even begin to imagine such possibilities as every aspect of their higher dimensional existance is utterly beyond anything we could ever comprehend... so meh

Dark_Angel · 26 Mar 2008 at 16:37

Ulfhedjinn said:
I think I know what you mean now, but I'm not entirely sure.

If you travel out into space in a straight line eventually you will reach the edge of our galaxy and leave it. You will have an immense empty space after that but eventually you are going to enter the star field of another galaxy, and this will probably go on forever until you reach the edge of the universe.

I won't get into the "edge of the universe" or curved universe stuff as I have really don't know anything about that. Not through lack of trying I might add, just because for some reason I can't get my head around it.

Feel like an attempt at a basic explanation, or perhaps nudge me in the direction of some reading material?

Glaucus · 26 Mar 2008 at 16:38

Dark_Angel said:
I mean, what the hell happens if there is an edge and you reach and and take the plundge off? do you suddenly appear in a different universe

That all depends on what theory you want to put your name on.
Some theory's say the universe is a spiral or doughnut shape. So you leave the edge of the universe and you'll enter the other side, sort of.

platypus · 26 Mar 2008 at 16:38

Spektor said:
It doesn't, a universe is not a multiverse, our particular bubble of space-time is finite and will cease to be

No, a universe can be part of a multiverse. I know of no scientific evidence to claim that our space-time is finite. Can you show me?

KaHn · 26 Mar 2008 at 16:39

KaHn

Booner! · 26 Mar 2008 at 16:40

Maybe there is a brick wall..? but what is on the other side of said wall? and what colour would it be? and would we see it? argghhh *boom* *head explodes*

spp · 26 Mar 2008 at 16:41

Truth is no one knows if the universe is infinite. The standard model of cosmology puts the curvature of the universe to be about 0, which is a flat universe (infinite). For all my computer simulations modeling dark energy I set the curvature of the universe to be zero.

As for 4% of the universe being made of atoms, that's correct, at least from an observational pov. It appears that the 70% of the energy density of the universe is in a form known as dark energy (an area I work in), and 26% is in the form of a non baryonic source, dark energy (here baryonic refers to baryons and leptons).

p4radox · 26 Mar 2008 at 16:42

I've never understood what a multiverse actually is. I always thought that the universe encompassed everything in existence, so what's the need for more of them?

Unless the universe only contains the spatial and temporal stuff, in which case, what do the others contain?