Altheia
Dec 18 2006, 03:02 PM
A cosmic hall of mirrors
Feature: September 2005
Most astronomers think that the universe is infinite, but recent measurements suggest that it could be finite and relatively small. Indeed, as Jean-Pierre Luminet describes, we could be living in an exotic universe shaped rather like a football
At a Glance: Cosmic topology
• There are three possibilities for the curvature of the universe: space can be flat, spherical or hyperbolic
• The geometry of the universe depends on its curvature and also on its topology, which governs the way space is connected and so determines if it is finite or infinite
• Measurements of the cosmic microwave background constrain the curvature of the universe and provide hints about its topology
• Recent data suggest that the universe might be multiply connected, like the left- and right-hand sides of the screen in a computer game
• Since the early 1990s the number of cosmo-topologists around the world has grown to more than 50
full article:
http://physicsweb.org/articles/world/18/9/3
Isis2200
Dec 20 2006, 12:01 AM
QUOTE(Altheia @ Dec 18 2006, 10:02 AM) [snapback]1466319[/snapback]
A cosmic hall of mirrors
Feature: September 2005
Most astronomers think that the universe is infinite, but recent measurements suggest that it could be finite and relatively small. Indeed, as Jean-Pierre Luminet describes, we could be living in an exotic universe shaped rather like a football
At a Glance: Cosmic topology
• There are three possibilities for the curvature of the universe: space can be flat, spherical or hyperbolic
• The geometry of the universe depends on its curvature and also on its topology, which governs the way space is connected and so determines if it is finite or infinite
• Measurements of the cosmic microwave background constrain the curvature of the universe and provide hints about its topology
• Recent data suggest that the universe might be multiply connected, like the left- and right-hand sides of the screen in a computer game
• Since the early 1990s the number of cosmo-topologists around the world has grown to more than 50
full article:
http://physicsweb.org/articles/world/18/9/3Hi Altheia: Interesting data.
I believe the universe is finite, but that's just my opinion.
http://ashiana.conforums.com/index.cgi~ Isis
Alex01
Dec 21 2006, 06:06 PM
The universe is finite. Space is infinite. If space was finite we would se the same stars and galaxies on the right and on the left.
Unforgiven
Dec 23 2006, 11:08 AM
The universe is infinite.
Altheia
Dec 23 2006, 12:16 PM
but how can something infinite grow? which is what the universe is doing according to the majority of respectable scientists.
Alex01
Dec 23 2006, 05:08 PM
QUOTE(Altheia @ Dec 23 2006, 01:16 PM) [snapback]1472040[/snapback]
but how can something infinite grow? which is what the universe is doing according to the majority of respectable scientists.
king_ivan
Dec 24 2006, 07:16 AM
I believe it is infinite.. how can it grow if they cant even measure its parameters? Even if it was finite what could possibly be outside it?.. Its unimaginable
Cadetak
Dec 30 2006, 04:58 AM
QUOTE(Altheia @ Dec 23 2006, 07:16 AM) [snapback]1472040[/snapback]
but how can something infinite grow? which is what the universe is doing according to the majority of respectable scientists.
The stars, planets, moons, asteroids, etc. are all finite, there is a certain amount of them out there...there isn't an infinite number of stars in the universe. The empty space is infinite though...the planets and stars are just moving further into the infinite emptiness.
arkland
Jan 1 2007, 09:30 PM
Sorry annie WRONG!!!
Clobhair-cean
Jan 2 2007, 09:19 AM
QUOTE(Altheia @ Dec 23 2006, 01:16 PM) [snapback]1472040[/snapback]
but how can something infinite grow? which is what the universe is doing according to the majority of respectable scientists.
This is the basis of infiniteness... If a finite set of objects constantly gains a new object every now and then it is infinite because it does not end. It's like with numbers: 1+1+1+1+1+1.... and on and on forever. Or, the universe is finite, but its far too big for human comprehension (I can't even full comprehend the distance between Munich and Budapest and I'm not that obtuse)
Altheia
Jan 2 2007, 12:29 PM
QUOTE(Clobhair-cean @ Jan 2 2007, 10:19 AM) [snapback]1482483[/snapback]
This is the basis of infiniteness... If a finite set of objects constantly gains a new object every now and then it is infinite because it does not end. It's like with numbers: 1+1+1+1+1+1.... and on and on forever. Or, the universe is finite, but its far too big for human comprehension (I can't even full comprehend the distance between Munich and Budapest and I'm not that obtuse)
You're saying that it could grow to infiniteness. That could be yes. Untill it implodes or whatever. But in order to know that something grows you first have to know it's measurements. So if it's infinite it cannot grow, yet our universe seems to. So following that logic that would mean the universe is finit.
Adam2006
Jan 2 2007, 01:13 PM
There was a very good article in the newscientist magazine on it, however you have to pay for the magazine and the article online

I have it but i'm not typing but 4 pages of text

. It gives diagrams and everything.
Don't click here....
artymoon
Jan 2 2007, 01:21 PM
QUOTE(Ghostkol @ Dec 21 2006, 01:06 PM) [snapback]1470155[/snapback]
The universe is finite. Space is infinite. If space was finite we would se the same stars and galaxies on the right and on the left.
I agree.
Lilly
Jan 2 2007, 01:35 PM
Here's an interesting article from Space.com.
QUOTE
If the universe is closed, though, then what is beyond the universe? Weeks took his best shot at answering this confounding question:
"The universe is finite," he said, "but there's no boundary to it," implying that there is no beyond, or that if there is, then its nature is left to your imagination and is outside the closed system that astronomers can ever hope to see.
Personally, I try not to think about it too much...tends to give me a headache!
Clobhair-cean
Jan 2 2007, 09:49 PM
QUOTE(Altheia @ Jan 2 2007, 01:29 PM) [snapback]1482586[/snapback]
You're saying that it could grow to infiniteness. That could be yes. Untill it implodes or whatever. But in order to know that something grows you first have to know it's measurements. So if it's infinite it cannot grow, yet our universe seems to. So following that logic that would mean the universe is finit.
But if it's constantly growing you cannot measure it because it will be bigger by the time you've finished, so you can start the measuring all over again...
StarMountainKid
Apr 30 2007, 01:31 AM
I think the concept of infinity is a complex one. If we consider the Big Bang the beginning of our universe, and that the universe has been expanding ever since, I would say the universe can't be infinite because it had a starting point in time. For such an expanding universe to be infinite an infinite amount of time would have had to elapse since the BB.
Also, as far as a finite number of stars expanding into an infinite space, the universe isn't expanding into any pre-existing space, space itself 'is' the universe...space itself is what is expanding. There is no space 'outside' the universe for it to expand into.
Physical infinity would involve volume and time. There may exist an infinite number of universes, each creating their own finite spacetimes from their own BB creations, but each individual universe would be finite. Thinking about it in this way, there was never the 'first' universe and there will never be the 'last' because time only exists within each universe. If we could imagine the whole of these infinite number of universes existing, there is still nothing 'outside' of them, no infinite volume for these universes to exist within.
Mathematicians deal with infinities, but I don't think any physical infinity can exist. An infinite physical reality would require, for instance, having existed for an infinite amount of time in the past, and existing for an infinite amount of time in the future. Since within this reality a clock is always ticking, there will always be another future moment, and an infinite future will never be realized. Just some thoughts from a new member.
Eieam Wun
May 2 2007, 02:17 PM
I think the universe can be finite have an actual physical barrier and still expand... Solid matter can condense on a micro scale or become denser and on a macro scale can change from a solid to a liquid or a gas expand then resolidify. Anything is plausible, infact I wrote a paper on exactly how such a process could work. As to what is beyond the barrier, it's anyones guess.
Kleon
May 4 2007, 09:24 AM
The last book I read about that said that the universe itself is finite and is of an elliptical shape, which means that there could be more than one universe out there in the infinite space.
I'll check the book again, it's been a while
nn23
May 4 2007, 10:40 AM
Yeah, but how could they possibly prove that?
Emma_Acid
May 10 2007, 01:43 PM
Given that the universe is expanding (something that has been emperically observed) it must have therefore had a smaller state, therefore a beginning*, and therefore it must be finite.
It is also not true that space is infinite while the universe is finite. Space and time are intrinsically linked to the laws of this universe. We've known this for over 100 years. So its impossible for one - say, space - to be infinite yet the other (the universe) finite.
It is important to realise that there isn't an "infinite" amount of space outside of out universe, the laws simply don't work that way. Space as we know it ONLY exists inside our universe.
(*something we can only guess at, as we simply don't have the mathematical tools to delve that deeply.... yet)
Alex01
May 15 2007, 08:46 AM
Guys, space is the emptyness, emptyness cannoot be finite. The Universe is finite because it is just matter in emptyness, and that emptyness is space. As simple as that. At the end of the universe, all the matter. There is more emptyness, thats why it is black, but the universe is constantly explanding in more of that emptyness and will continue too.
Isis2200
May 15 2007, 03:01 PM
QUOTE(Eieam Wun @ May 2 2007, 09:17 AM) [snapback]1655806[/snapback]
I think the universe can be finite have an actual physical barrier and still expand... Solid matter can condense on a micro scale or become denser and on a macro scale can change from a solid to a liquid or a gas expand then resolidify. Anything is plausible, infact I wrote a paper on exactly how such a process could work. As to what is beyond the barrier, it's anyones guess.
Hi Eieam Wun:
So what you're saying is that it could be comparable to air inside a balloon whereby as the air is pushed through the balloon, the balloon expands. So if that barrier is very strong, it would cause the universe to contract, and if the barrier would not very strong(as is a balloon), the barrier would break from the force of the expansion of the universe and thus reveal what could be outside that barrier.
Interesting.
Celumnaz
May 17 2007, 07:01 PM
universe expansion may be faulty observation due to limited perspective, shifts warped by time may give false color etc...
planet/star expansion is fairly well confirmed no? those are finite things.
If the universe is finite, or some type of closed system, it is possible it can still expand, possibly infinately.
my favorite theory so far is the one that says if you leave the milky way in a straight line, eventually you will see the milky way approaching from the front
fits with the megaverse/multiverse thing, not that I completely subscribe to that either
bee
May 17 2007, 08:59 PM
I had this thought when looking at the stars, one night....
You know how things appear solid to us, but really there is loads of space in every 'atom' (or what-ever you want to call it).
I've heard the analogy that if an atom was the size of a football pitch...then the nucleus and electrons would be like tiny marbles.
Anyway...I looked at the stars and wondered if all the stars were seen at the same distance....would there be a 'wall' of light.
In other words...is the universe a sphere of light?
Do the stars make the edge of the sphere, but they seem to be far apart to us...like the content of atom would if we could see it.
Don't know if this makes sense...but I surpose I'm saying that I think the universe is finite...and that the edge of it, is what-ever it is that we perceive as light.
Maybe, perhaps, possibly...who knows? Just wanted to share this thought.
Calista
May 18 2007, 03:01 AM
I truly believe this question is beyond the comprehension of human intelligence. Are we a universe inside of a larger universe? If the Universe is finit, what is beyond the universe? Far too complicated.
spikeman25
May 18 2007, 05:47 AM
QUOTE(Altheia @ Dec 23 2006, 12:16 PM) [snapback]1472040[/snapback]
but how can something infinite grow? which is what the universe is doing according to the majority of respectable scientists.
Something that has always existed can certainly grow. Scientists don't have all the answers, All they can do is take an educated guess when it comes to this.
Einstein
May 27 2007, 03:09 PM
Maybe there are many universe we may just be one of it.What i am saying is that we are like a football field on earth but there are many planet.Like air inside the water but trying to expand as there are many bubble thats the small universe. What will happen if we are living in this universe that are expanding always?.If alien exist they maybe on this universe or other universe.Untill we classify the detail about what was there before universe.(Explain)Maybe like water ,universe is like air .
This is self opinnion
By FanofEinstein
May 27 Year 2007
Time 11:09
Singapore
when.i.am.queen.
May 28 2007, 07:20 AM
The other day we were discussing this in class, and we came down to the problem of defining what the univesre really is.
Some people say that it is where there was matter, and others say that it was everywhere.
So if universe was defined by where there is matter, and it is indeed an elliptical shape, then past the last atom of matter on the outer rim is not universe.
Hence that it is finite.
But if the other definition is your thing, the universe is infitine, as there is no end.
Captain Kolak
Jun 3 2007, 12:10 AM
INFINATE!!!!!!!!
Why? Our univers does not have a clearly defined edge. It is just energy and light expanding. And it is becoming more dilute the further it expands. Like if you drop a rock into a calm pool. The waves are still present far away but hard to notice. Until they die away. And for it to expand, it must expand into something. And in this case nothing is something (Space).
Isis2200
Jul 16 2007, 04:22 AM
QUOTE(when.i.am.queen. @ May 28 2007, 02:20 AM)

The other day we were discussing this in class, and we came down to the problem of defining what the univesre really is.
Some people say that it is where there was matter, and others say that it was everywhere.
So if universe was defined by where there is matter, and it is indeed an elliptical shape, then past the last atom of matter on the outer rim is not universe.
Hence that it is finite.
But if the other definition is your thing, the universe is infitine, as there is no end.
Well, I for one, believe it's finite(just my personal opinion.) What's your opinion, Queen?
REBEL
Jul 16 2007, 04:53 AM
IMO, looking at it from a human perspective here on this tiny grain of sand called earth...Yes it is infinite.
camlax
Jul 16 2007, 04:54 AM
The universe is infinite, the matter that exists withing the universe is finite. A newer hypothesis is our universe is an out pocketing of a larger universe.
Isis2200
Jul 16 2007, 05:22 AM
When I was a teen, I remember hearing about some scientists that detected some type of barrier or wall at the fringes of our universe. Now, I can't comment on that too much because I don't know all the facts.
But recently, I heard an interview with a physicist who discussed the upcoming CERN experiment. They believe that when that happens and they use these high energy particle accelerators, there is a possibility they could create mini-universes.
Years ago, I thought that it was impossible that our universe could be finite because of the vastness of it. Our human minds cannot even fathom how big the universe is.
Then about 6 months ago someone sent me a diagram showing how big the earth is compared to other celestial bodies. We are so minute in the realm of things, and especially when you compare the gigantic Antares to the earth. At one point on the scale, the earth disappears entirely. This shows how very small we are indeed.
The same physicist mentioned above also stated what I believe could be true, and that is, if you believe in multi-universes, we could be a very tiny universe. He also stated something shocking but possible and that is
"What if someone in another dimension created our universe by means of one of these high-energy particle accelerators."
As my friend would say "It's definitely something to chew on."
questionmark
Jul 16 2007, 01:13 PM
OK guys, this is what I remember from my discussion with cosmologists:
The matter occupied space in the universe is expanding and according to cosmologists ever since the big bang that created it. What is unclear is what lies beyond the confines of the matter occupied space. Some claim that there is nothing into which the universe expands, which to me does not sound to logical. Others claim that it is a vacuum, which leaves place for speculation (as done before in this thread) that there could be another universe somewhere in that vacuum.
Now any of these theories give room to different theorems.
If the universe is finite expanding into nothing, it could at some point quit extending, stop and contract again.
If on the other side the universe is expanding into a vacuum it will keep expanding forever until it reaches the confines of that vacuum.
Now to the question: is it finite or infinite. There is no clear answer. For most purposes infinite is assumed because it makes better equations. If we assume that it is finite we would have to include other, mostly insignificant, parameters into cosmological theories.
As I can imagine we are as far as before. And that is because nobody really knows the answer yet.
camlax
Jul 17 2007, 02:23 AM
QUOTE(questionmark @ Jul 16 2007, 09:13 AM)

If the universe is finite expanding into nothing, it could at some point quit extending, stop and contract again.
If on the other side the universe is expanding into a vacuum it will keep expanding forever until it reaches the confines of that vacuum.
Actually there has been quite a building evidence that the acceleration of the universe wont slow down. Now what happens after this infinite expansion? I tend to like the heat death hypothesis, around 10
41 years and the universe is so far spread out that all protons decays! Better start selling your protons now.
questionmark
Jul 17 2007, 01:21 PM
QUOTE(camlax @ Jul 17 2007, 05:23 AM)

Actually there has been quite a building evidence that the acceleration of the universe wont slow down. Now what happens after this infinite expansion? I tend to like the heat death hypothesis, around 1041 years and the universe is so far spread out that all protons decays! Better start selling your protons now.
Which could be right, our problem is that we would need at least half of 10
41 years to confirm it. The other possibility is to get to the confines of the universe and have a look whats there.
Both wont happen in out lifetime so lets stay with hypothesis. That way we have something to do in those could winter nights when we sit in front of our fire with a bottle of Bordeaux. (Or as a good friend of mine says : When a physicist gets old his interest in cosmology and red wine grows)
Captain Kolak
Jul 18 2007, 07:16 PM
why do people think the universe as something solid? The edge of the universe is just radiation and all that ws present and the beggining of the universe. If the universe is expanding (which it is) then it is finate. Saying that the universe is expanding and that it is infinate is somewat illogical. True, it has no size because it is expanding, but that does not make it infinate. As for what it is expanding into, space. Space as in a vaccum. A vaccum that can be traversed, so then this "space" is both finite and infinate. Because you can keep moving in it forever but if your not mocing through it, then it doesn't relly exist. Also, this fits well into the multi universe theory and heat death end of the universe theory. Also, just because we humans do not have to ability to comprhend the size of the universe and all doesnt make it infinate. It has a size and certain amount of energy/matter/ etc.
Harte
Jul 18 2007, 10:32 PM
Captain,
You need to go and read the posts in this thread to see why you're wrong about the expansion:
My Favorite ThreadHarte
Captain Kolak
Jul 19 2007, 12:45 AM
Well obviously I'm not saying that I'm right. (I have a tendancy to sound like that......sry....), i ws reading the link u had but i still sorta stand by what I said.
Cap'n
Harte
Jul 20 2007, 10:15 PM
QUOTE(Captain Kolak @ Jul 18 2007, 07:45 PM)

Well obviously I'm not saying that I'm right. (I have a tendancy to sound like that......sry....), i ws reading the link u had but i still sorta stand by what I said.
Cap'n
Cap'n
Whatever you want to believe is fine with me, as long as you realize that you're only going on faith and a gut feeling, while the people at links available in the thread I linked spend their lives figuring this stuff out and making physical observations of the pertinant information.
If you read far enough into the linked thread, you'll see that several posters there, myself included, managed to change a few minds on this subject, or at least lead people to information that showed them what we were talking about.
The universe cannot possibly be expanding into empty space, for instance. This is because it is
only the space occupied by the universe that is expanding , and not the mass expanding through the space. IOW, the expanding space is carrying the mass along with it. There is simply no question that this is true. You may, of course, choose not to believe it - like I said. But that in no way changes the fact of the matter.
It's not like an explosion where the mass is flung out
through space. In the case of the Big Bang, it was not a ball of mass that exploded, it was a ball of spacetime.
Harte
Eieam Wun
May 22 2008, 03:24 AM
QUOTE (Isis2200 @ May 15 2007, 11:01 AM)

Hi Eieam Wun:
So what you're saying is that it could be comparable to air inside a balloon whereby as the air is pushed through the balloon, the balloon expands. So if that barrier is very strong, it would cause the universe to contract, and if the barrier would not very strong(as is a balloon), the barrier would break from the force of the expansion of the universe and thus reveal what could be outside that barrier.
Interesting.

...mmm not quite what I had in mind. More like a physical barrier that is at some level solid that changes periodically into a gaseous stage allowing it to expand outward then resolidifying back into a solid thus creating more space kinda what I meant.
the whynsos
Dark Ninja Alien
May 22 2008, 02:18 PM
its kinda obvious that it's round, all the planets and stars we see are round, the expansion could be compared to something that can expand on earth, for example foam.
Waspie_Dwarf
May 22 2008, 06:33 PM
QUOTE (dr alien @ May 22 2008, 03:18 PM)

its kinda obvious that it's round,
It is?
QUOTE (dr alien @ May 22 2008, 03:18 PM)

all the planets and stars we see are round.
Even if this were true (it isn't, see below) what about galaxies, the vast majority of which are nothing like spherical.
To say that all the planets and stars we see are round is simply incorrect. Jupiter, for example, is noticeably oblate (flattened at the poles). This is as a result of its fast rotation rate. Many stars are very oblate. Smaller objects, such as asteroids, are mostly irregular.
Why you think the shape of stars and galaxies has any barring on the overall shape of the universe I can not even hazard a guess at.
Dark Ninja Alien
May 22 2008, 08:14 PM
i said that its round, that means that there are no corners, how often do you see a comet shaped like a cube.
Waspie_Dwarf
May 22 2008, 08:16 PM
QUOTE (dr alien @ May 22 2008, 09:14 PM)

i said that its round, that means that there are no corners, how often do you see a comet shaped like a cube.
Have you seen a picture of a comet nucleus? Clearly not because round is not the word you would use if you had.
DONTEATUS
May 22 2008, 11:20 PM
If Slartibartfast really did the proto-type of the known universe then by all means it must be a marvalous thing to behold .It maybe any shape we see it to be .What was that est on the end again? My protons are all locked up and mutual funds Im in deep $#@p.DONTEATUS
Alex01
May 23 2008, 03:04 PM
QUOTE (Harte @ Jul 19 2007, 12:32 AM)

Captain,
You need to go and read the posts in this thread to see why you're wrong about the expansion:
My Favorite ThreadHarte
The thread where I was completely wrong and thought I was completely right all leading to a bad interpretation of mine of the Big Bang theory. All contraire here, I dislike that thread.
Anyhow, I thank you Harte for spending time to debate the subject and clearing up my bad interpretation which I now feel completely ashamed off and this being the reason for this post.
Harte
May 23 2008, 03:40 PM
QUOTE (Alex01 @ May 23 2008, 10:04 AM)

The thread where I was completely wrong and thought I was completely right all leading to a bad interpretation of mine of the Big Bang theory. All contraire here, I dislike that thread.
Anyhow, I thank you Harte for spending time to debate the subject and clearing up my bad interpretation which I now feel completely ashamed off and this being the reason for this post.
Ashamed??!!
No need for that!
Look, my sister has been an engineer for NASA for over twenty years and she still refuses to believe it.
So, no worries and you should be proud of yourself for being open enough to think seriously about such a deep subject and overcome your own preconceptions about it.
Thumbs up to you!
Harte
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