infinite universe?

[treaclefight]

says who, and how did they prove it? (i am not a nobel winning scientist so im probably going to have problems understanding the actual answer if there is one, but all opinions count and are welcomed as far as im concerned)

[darth vader]

I was led to believe that the universe is finite, but expanding. (big bang theory). Do you mean more precisely the space to which the universe is expanding in? only God can answer that one (assuming you believe in one)

[woofgang]

try Stephen Hawking's a brief history of time, or his the universe in a nutshell and be prepared to read it slowly!!

[treaclefight]

no disrespect to the ides of reading stephen hawking woofgang, but i'm reading for a law degree at the moment and judges waffling on for page after page is as much reading as i can take at the moment, could you sum up hawkings books into one nice juicy soundbite for me? asking a bit much aren't i :-)

[sddsddean]

Th e true answer is that no one really knows. I think The Hitch Hikers Guide to the Galaxy sums it up best. " The Universe: Size: Infinite(as far as anyone knows)" The real problem comes with understanding if the universe is not infinite, what is the other side of the 'border'?

[treaclefight]

it's looking like maybe the universe isn't infinite...we might be alone guys :-(

[treaclefight]

in answer to darth, my religious view tend towards buddhism if anything, in that i belive in causality rather than god...i think i might be in trouble if your right

[anthomson]

I have read both these books and I don't think they will conclusively answer your question. At this moment we can only postulate what if anything is outside our finite universe. In 'The Universe in a Nutshell' Hawkings talks about branes, where our universe might exist on the surface of a brane. He gives the analogy of brane being like a bubble forming out of nothing in boiling water. Although we could never see any other branes ( or bubbles ) we might be effected by their gravitational fields. This may explain all the missing mass we would expect to find in our universe.

[Squirrel]

Stop me if I'm wrong, but it could just be that some of the matter in the Universe has been flung so forcibly outwards into space that it is almost beyond the effect of all the gravity of all the other matter? For example, through chance there might be a load of small pebbles that are travelling at � the speed of light out into nothingness, but they're being slowed down by the gravity of the universe that is light years behind them. The pebbles could travel so fast and be so far away from everything that they would only encounter the slightest opposing force to slow them down. And if that was to happen all around the universe - runaway particles flying off in every direction - then it would become very big indeed, and yet never infinite, because the matter would always be pulled back to the centre of mass, even if it took a thousand Big Bangs.

[anthomson]

I think that are our universe curves back in on to itself due to gravity - so it looks pretty much the same whereever your are observing fit from - it has no centre and no edge. The big bang occurred almost uniformly throughout the entire universe hence we see the 3k background radiation (the light from the big bang) in all directions. Our universe is therefore essentially a closed system and this is why we can't see the 'empty' infinite space 'outside' of the universe.

[treaclefight]

thankyou ant, that's a good mental picture that i can understand, i've also now got some idea why people have come up with the theory that there are other universes. i'm learning alot today, i feel like neo when he gets plugged in to the training programs...now who can teach me kung fu in one sentence?

[JohnPPotts]

Just because the Universe is finite doesn't mean it has an edge - think of the Earth: it's finite yet you'll never "fall off the edge" ("finite but unbounded") - similarly with the Universe (only you have to think in curved space-time!). As for Kung Fu - just remember "There is no spoon!"

[treaclefight]

potts answer a bit more challenging to get my head round, we're always on the outside of the earth so eventually we get back to the same place if we just keep going...is that going to happen if i set of into the universe too? i'm fascinated by this subject now. (oh, and "there is no spoon" has not helped me, ive still lost the ticklefight with the kung fu expert boyfriend)

[anthomson]

yep - if you had a very, very powerful telescope ( and a lot of time to kill ) what ever way you pointed it - you would see the back of your head.

[anthomson]

Stephen Hawkings book also says that time may work in exactly the same i.e. it has no edges, no start or end. So if you keeping going forward in time you would get back to the time you started at. Unfortunetely my brain is full so I can't really conceptualise this.

[treaclefight]

uhu, i can get my head round space curving back on itself, but not time, i cant describe what time is, but it doesn't do things like curve back on itself in my idea of it, however i fear that if post the question "what is time" then the question police are going to come and lock me up

[woofgang]

If you are thinking about time and universes, a really great read is The globe, science of the disc world

[treaclefight]

thankyou woof, the books referred to above are going on my amazon wishlist, perhaps i should post again when ive read them (but that might be a long long time, snowed under with reading here) :-)

[treaclefight]

i had suspected that this was so

[hal]

I have read several books on this subject, the majority of which were difficult and too technical. However I recently read "How The Universe Got Its Spots" by Janna Levin. It is excellent, clearly written, intended for the lay reader and a wonderful summary of the range of theories about the nature and extent of the universe. You will not find a definitive answer, because there isn't one at the moment (and may well never be one), but it is an enjoyable and thought provoking read on a very thought provoking subject.