Is the universe infinite?

[lapis]

I'm not really sure where to post this, but religious/philosophical topics also seem to go here.

Is the universe limited to what we can observe or is it infinite? The visible universe is finite but we can never travel outside since we have the speed of light as a limit to how fast we can travel. So even though we can never find a conclusive answer, we can always wonder what's outside the visible universe. Does existence abrubtly end at it's borders, or do you end up on the other side of the universe if you cross the line (some sort of four-dimensional doughnut shaped universe)?

And if the universe is infinite, does it contain an infinite amount of matter? Physicists always speak of the Big Bang and matter being concentrated, but are they just referring to the matter in the visible universe? Because if there is infinite matter and space in the universe, then all possible forms of the world as we know it will exist (an infinte amount of times). Take the monkeys and the typewriters producing Shakespeare for example - if infinite matter is true then somewhere in the universe there will be a world where someone with your name and body lives, with the same life or with different experiences.

[MoralLibertarian]

I heard that it's round, just like the earth. If you travel enough in one direction, you'll come back from the opposite direction.

[A-Carrot-By-Dr-Riot]

I'm pretty sure that the current consensus is that it is finite in it's size and contents, but the size is constantly expanding at high speed outward in all directions. Traveling beyond the borders is impossible as it would require one to go faster than the speed of light.

[Jinzoa]

makes you think doesnt it? well alot of people who believe in the big bang say there will be a big crunch, the entire opposite of the bang where the whole universe collapses on itself as there is not enough dark matter to supposrt its constant growth. So everything goes back to the size of atom and then bang, big bang happens again.

i find that theory debatable though.

[A-Carrot-By-Dr-Riot]

Nope, the current theory is the universe is accelerating in it's expansion. It's sorta depressing but the world ends in a whimper, not a bang.

[Jinzoa]

At 12/22/05 11:00 AM, Dr_Arbitrary wrote: Nope, the current theory is the universe is accelerating in it's expansion. It's sorta depressing but the world ends in a whimper, not a bang.

i never said it ends in a bang, i said everything goes to the size of an atom(about that) and then the big bang repeats itself.

According to the big bang model, if there is sufficient matter in the universe, gravitational forces will halt the expanding universe, and eventually the universe will start to collapse, ending up in a big crunch. However, if there is insufficient matter, the universe will expand forever, and the universe will eventually cool off completely and die a slow heat death.
Although of course exceedingly difficult, astronomers have attempted to measure the total mass of the universe, and found that it was less than that required for the big crunch to take place. However, there may be what is called dark matter in the universe which may provide the necessary mass to halt the expansion. This dark matter, by its nature, is difficult to detect as it cannot be seen, and so indirect measurements of its presence have been made by inferring its influence on visible objects.

[morefngdbs]

As best as our puny little brains can comprehend .
it is infinite.

[A-Carrot-By-Dr-Riot]

At 12/22/05 11:10 AM, Jinzoa wrote: i never said it ends in a bang, i said everything goes to the size of an atom(about that) and then the big bang repeats itself.

If that's true, the beginning is the end, and there's a bang in there somewhere.

[Jinzoa]

good point.

[lapis]

At 12/22/05 11:10 AM, Jinzoa wrote: i never said it ends in a bang, i said everything goes to the size of an atom(about that) and then the big bang repeats itself.

So if the universe is finite in space, is there anything outside it?

At 12/22/05 10:52 AM, PCHoliday wrote: I heard that it's round, just like the earth. If you travel enough in one direction, you'll come back from the opposite direction.

It's possible, but then we'd have to imagine the universe as some sort of four-dimensional shape. If the universe really is a three-dimensional globe and you approach the border then you'll have hit a limit (1).
If the universe is like the surface of a doughnut then you'll reach your old location again when you travel any direction for long enough (2). If the universe is more like the surface of a globe (3) then you'll reach your old location again if you travel any direction, but you'll first come across a point which is the exact opposite of your old location, which you'll reach if you travel any direction before you reach your old location. This is sort of hard for me to visualise though.

[GunCrave]

This may be an asinine opinion on my part deficient in fact or foundation, but I believe just as a chart of coordinates goes on forever, so do the limits of the universe.

[x-Toadenalin-x]

If you train your telescope on the sky directly north, you can see 'x' distance
If you look south, again, 'x' distance
East, west, north-east, south by south-west, always 'x' distance.

This leads you inescapably to one of two conclusions
1) The Earth is the centre of the Universe
2) The Observable Universe is smaller than the actual universe.

Since the actual universe cannot affect earth (we can never see further than the Observable Universe by definition), whether or not the universe is infinite is unknowable.

Since even the very best scientists can, at best, guess, I'm going to have to say that this argument should more concerned with the implications of an infinite universe than the existance of said universe.

[Wadger]

At 12/22/05 10:52 AM, PCHoliday wrote: I heard that it's round, just like the earth. If you travel enough in one direction, you'll come back from the opposite direction.

if its round then what is on the outside of the round. their woud have to be something on the outside. Now if its infinite then their is nothing for it to be inside and it is their is nothing outside of it

interesting........................

[ReiperX]

I'm not sure, doubt anyone really knows for sure since infinity is well extremely hard to comprehend.

But the way think it is, is our universe is kidna like a galaxy, there are inifinate number of universes inside the infinity of the space outside of the universal bounderies that exist of our expanding universe and always has been which would explain where the oringinal energy from the big bang came from.

Kinda of like there are solar systems in this galaxy, galaxies in this universe, universes in existances, maybe alternate existances withing whatever would be outside of existances.

[ReiperX]

At 12/22/05 11:23 AM, Dr_Arbitrary wrote:

At 12/22/05 11:10 AM, Jinzoa wrote: i never said it ends in a bang, i said everything goes to the size of an atom(about that) and then the big bang repeats itself.

If that's true, the beginning is the end, and there's a bang in there somewhere.

Well since a bang is audible, and there wouldn't be anything outside for the bang to travel since sound needs matter to travel thru there would be silence would there not? Maybe a flash of light.

So could it just be the big flash not the big bang?

[Wadger]

i like your idea it definatly could fit.

the problem is i dont think humans are at the moment capable of comprehending the entire universe. even if their is a limit on its size it is so huge that to look at it all would send you insane. i think we will have to work our way up

[lapis]

At 12/22/05 04:12 PM, ReiperX wrote: Well since a bang is audible, and there wouldn't be anything outside for the bang to travel since sound needs matter to travel thru there would be silence would there not? Maybe a flash of light.

So could it just be the big flash not the big bang?

The sound could go through the matter compressed into the mentioned atom, there won't be any sound outside it. If the matter expands faster than the sound spreads then the sound of the Big Bang wouldn't even ever die out. And if we assume the universe isn't finite and doesn't contain a finite amount of matter, then the sound could go through an infinite amount of matter.

[IllustriousPotentate]

At 12/22/05 11:39 AM, lapis wrote:

At 12/22/05 11:10 AM, Jinzoa wrote: i never said it ends in a bang, i said everything goes to the size of an atom(about that) and then the big bang repeats itself.

So if the universe is finite in space, is there anything outside it?

At 12/22/05 10:52 AM, PCHoliday wrote: I heard that it's round, just like the earth. If you travel enough in one direction, you'll come back from the opposite direction.

It's possible, but then we'd have to imagine the universe as some sort of four-dimensional shape. If the universe really is a three-dimensional globe and you approach the border then you'll have hit a limit (1).
If the universe is like the surface of a doughnut then you'll reach your old location again when you travel any direction for long enough (2). If the universe is more like the surface of a globe (3) then you'll reach your old location again if you travel any direction, but you'll first come across a point which is the exact opposite of your old location, which you'll reach if you travel any direction before you reach your old location. This is sort of hard for me to visualise though.

Ooh topology.

There are also theories that space time may resemble a Klein bottle. As a result, being embedded in space time, you could travel in any direction and return to your origin point, but your molecular structure would be completely reversed. Another outing would unreverse you. Some speculate that dark matter is a result of matter being reversed by the "Kleinbottletude" of the universe.

Of course, none of this will really help us. By the time the end game of the universe starts to occur, we'll have been dead for billions of years. However, it's still a fun exercise in science and thought.

[arz756]

Well einstein(or someone who new him) said something about a multiverse, an area that contains different univerises with different laws of physics and stuff like that. But since we're not going to live to see the day humans figure it out (unless the Raelians have their way) there isn't much of a reason to care.

[Redbob86]

Well, the universe is expanding, so I'm not certain it's "infinite" if it can continue to grow and expand.

[LolSatan]

At 12/22/05 11:18 AM, morefngdbs wrote: As best as our puny little brains can comprehend .
it is infinite.

That was uncalled for you jerk...you didn't even put a good reason why...

I think the universe could be a looping kind of thing, but at the same time, I think the whole universe is always expanding...king like creeeping like gas...hmmm....

[Redbob86]

Since the universe is expaning, I think the proper term would be that is is not "infinite", but rather "expanding infinitly".

[HockeyMitch]

nobody knows, nut i think its round like the earth. If you too far then you'll end up where you left off.

[Redbob86]

We truly won't know jack about the universe until we actually advance into to sci-fi "space age". We haven't traveled further than our own moon, and despite all the research we keep doing and all the theorizing on the universe, in the end it still doesn't add up to jack.

[lapis]

At 12/22/05 05:15 PM, BarbasolQMonkeybeans wrote: There are also theories that space time may resemble a Klein bottle.

Heh, cool. I never took topology but I looked it up on wikipedia. Interesting theory.

At 12/22/05 06:16 PM, Redbob86 wrote: Well, the universe is expanding, so I'm not certain it's "infinite" if it can continue to grow and expand.

It can be infinite but still expand. One infinite set can be bigger than the other infinite set (all numbers compared to only postitive number as an example). I'm not sure if this works for space time as well since it's uncountable, but it doesn't have to be a necessary restriction.

[Demosthenez]

Its infinite.

There is no outside of the universe so how can you define something in an even larger grouping (what I guess the universe would be in) if it is not in anything? The universe is the universe. It is infinite.

That is another reason I doubt the existence of a God. For there to be a God that is infinite he would have to BE the universe to be infinite. Otherwise he really cant be outisde it controlling it unless we are gonna go for those we cant understand Gods ways crap.

[Wadger]

if its expanding what is it expanding into?

[morefngdbs]

At 12/22/05 06:23 PM, cereal_killer11 wrote: That was uncalled for you jerk...you didn't even put a good reason why...

; the reason why,Is because your brain is too puny.

I think the universe could be a looping kind of thing, but at the same time, I think the whole universe is always expanding...king like creeeping like gas...hmmm....

;
I agree with you.
you are loopy, and probably creepy as well.
merry xmas from an ever expanding universe.

[JungaLunga]

i personally thnk that if u go out far enough, that you will meet an end like an eggshell sorta, and if u get through it u will find that we r rlly just like an atom in a blade of grass in some other dimension or somethng....i guess im just wierd like that

[Ravens-Grin]

At 12/22/05 10:50 AM, lapis wrote: And if the universe is infinite, does it contain an infinite amount of matter? Physicists always speak of the Big Bang and matter being concentrated, but are they just referring to the matter in the visible universe?

Have you ever thought that big bang was just a minor event in the whole scheme of the universe? A big bang for every galaxy maybe?