17 replies to this topic

[forever freedom]

Astronomers say Universe is small and finite.


Well if that was the case, a universe with 56 Billion light years of lenght "only", there would be higher chances that we are alone in the universe (although i can't really picture what 56 billion light years must mean in terms of size). If the theory that says that after the singularity kicks in we are going to "own" the universe is true, then the answer to the paradox of why no alien race has already done it would be that we are indeed the first ones to get to such a developed stage.


Although 56 billion light years is a lot of space for intelligent species to come to existence, maybe and probably it is indeed very very hard for intelligent species such as ours to exist in "only" 56 billion light years of lenght. Either that, or the singularity as some of us envision it isn't true. Or it's just that this theory of the doughnut-shaped universe is sham.

[eternaltraveler]

just because the universe is a finite distance doesn't mean we would be able to cover it even in infinite time. That is because the universe is growing. see hubble limit

Edited by elrond, 27 May 2008 - 09:04 PM.

[Luna]

Don't forget they mean that the content is probably finite, the universe itself (vacuum) is infinite.
Which might also give us a good idea on vacuum energy.
Now, is space itself is expanding, it probably proves zero point energy even more.

[VictorBjoerk]

How can the university expand faster than the speed of light?How can the astronomers imagine a finite universe?What would be outside it?

[PWAIN]

just because the universe is a finite distance doesn't mean we would be able to cover it even in infinite time. That is because the universe is growing. see hubble limit

The hubble limit applies to the matter moving within the universe. Traditionally this is considered to be a function of space expanding (hence the reason that things can appear to move faster than light (relative to the space they are in, they don't). The article appear to imply that space is a pre determined size and that only the matter is moving out into it. If that is the case, eventually the matter will reach the limit and basically reappear on the other side of the universe. Ultimately this would mean that we would be able to reach every point of the universe with sufficient time. It is only the apparent infinity of space expansion that the hubble limit uses, when that is taken away, complete exploration becomes ultimately possible.

[Lazarus Long]

It seems appropriate to suggest reading this article here too since what we are really talking about is space/time not just space.

http://www.sciam.com...o...rrow&page=6
Does Time Run Backward in Other Universes?
One of the most basic facts of life is that the future looks different from the past. But on a grand cosmological scale, they may look the same
By Sean M. Carroll

Interestingly enough some of the aspects of this suggestion coincide with the closed universe model though the authors are not proposing a specific topology or size. They are however describing a finite model in a way. The article is worth the read.

[forever freedom]

How can the astronomers imagine a finite universe?What would be outside it?

It could be nothing, could be other universes, could be a void, or some other stuff... no one has been there (as far as i know ) so no one really knows.

[DukeNukem]

>>> Don't forget they mean that the content is probably finite, the universe itself (vacuum) is infinite. <<<

I think they mean that the universe itself is limited, meaning that it has a limited volume. This makes far, far more sense than an infinite volume.

>>> How can the university expand faster than the speed of light? How can the astronomers imagine a finite universe? What would be outside it? <<<

These are extreme lay-questions. They are best answered by reading books on the subject. Very quickly, Inflation Theory puts forth that very soon after the birth of our universe (and space-time), a short but rapid expansion of space itself occurred forcing all existing matter and energy apart, like raisins in bread. So, relative to local space, nothing moved faster than light (FTL), yet the distance between objects grew at an *apparent* FTL rate.

Astronomers easily imagine a finite universe, and many have hypothesized that this is the state of the universe for decades.

What would be outside it? There is no outside? This is like asking, Where is the edge of our planet? This sort of question is the most telling that you've not studied this subject. This question simply doesn't make sense.

[luminous]

It's funny, but it's equally hard for me to fathom the universe as finite or infinite. Wonder if there's something in between?

[forever freedom]

It's funny, but it's equally hard for me to fathom the universe as finite or infinite. Wonder if there's something in between?

What do you mean? What could be between finite and infinite?

[VictorBjoerk]

A human brain isn't able to really grasp the fact that there should be a finite universe.Although the university may be wrapped around itself in a way that makes it impossible to detect anything "outside".

And that leads to the basic philosophical fact that we can't understand what nothing is.Although the earth has no edge it is still surrounded by something.

[affinity]

Astronomers also once said the sun orbited the earth. Don't put your money on anything just yet.

[VictorBjoerk]

It's funny, but it's equally hard for me to fathom the universe as finite or infinite. Wonder if there's something in between?

What could "In between" be? The microcosmos is equally striking as well

[Ben Simon]

What do you mean the earth has no edge?

I'm standing on it. Okay... so it's round. But it has an edge.

Possible stupid question. Before the big bang was there a void? Or a 'nothing' in an even more true sense of the word? Or was there no before because their was no time? Does their need to be matter for their to be space?

Oi...

Clearly I am no physicist. And yet you should hear me on the drums.

[affinity]

What do you mean the earth has no edge?

I'm standing on it. Okay... so it's round. But it has an edge.

Possible stupid question. Before the big bang was there a void? Or a 'nothing' in an even more true sense of the word? Or was there no before because their was no time? Does their need to be matter for their to be space?

Oi...

Clearly I am no physicist. And yet you should hear me on the drums.

Some say time does not exist as an actual force, just a perceptual measurement.

One possibility is that the universe expands, collapses infinitely, or until the matter escapes the gravity of the material universe.

Again don't make an assumption yet; just live and learn.

[VictorBjoerk]

there is no "edge" of the earth?

[luminous]

there is no "edge" of the earth?

I never noticed it myself until I fell off.

[forever freedom]

there is no "edge" of the earth?

I never noticed it myself until I fell off.

lol lol. i must be in a very light mood because i probably saw this as much funnier than it probably really is

how did you survive the fall