Does Space really go on forever?

[wyevilla]

Originally Posted by eeyore

but for space to have any dimensions - and thus be able to curve, there must be something surrounding it to define the dimension

Ah, Eeyore, you are still thinking in classical 3 dimensions - ie straight lines going on for ever. with curved space, "straight" lines will eventually end up at their origin. The curvature prevents anything leaving the universe and therefore prevents anything being outside of the boundaries of the universe.

As the universe expands its volume will increase as will the size of its boundary. (Analagous to the balloon being blown up. Except that nothing can exist or go beyond the boundary - light, straight lines, spacecraft or a God.)

[eeyore]

yes but for a boudary to exist something must be beyond it otr there can be no edge

[wyevilla]

The boundary is not solid but can be thought of as the paths taken by light (photons) or any other form of radiation as they travel apparently out and away from the universe but eventually curve back towards it under the control of gravity. I tend to think of the "edge " of the universe much like the "edge" of an atom where electrons are pinging into and out of existence. All are inevitably attracted back by the positively charged centre. But outside of this swirling mass there is nothingness.

Sorry, but I can only think in analogies as this is the only way I can grasp what are very alien concepts. Our problem is that as a species our self awareness has evolved in a Newtonian world of three dimensions of space, one of time and to be of a size in which classical physics seems to provide an accurate description of how thing interact. Once you get to something the size of the universe (or for that matter to the size of an atom) what appears to be common sense breaks down.

[cresshead101]

aaarrrgghh!i'm so confused.but i finally know th REAL answer.when space ends there is a giant marshmallow garden full of mutant bunnies and super intellligentpidgles.these creatures control everythin,and the only thing they eat is wabbers and chupa-chups.sure,the human brain can keep thinking up theories,but we'll never really know anything for sure.the laws of space don't have to reflect the human's theory.
......i think,anyway.... (well,that's just my theory...)

[petermcgain]

Just in case you wanted to read an interesting analogy which refers to the infinite universe you might want to read The Library of Babel, a short story by Jorge Luis Borges. It's about an interlocking hexagonal library that goes on for ever in every direction with every possible, random, and often meaningless, permutation of the written word in every language. Quite mind blowing and the sort of short story that stays with you long after you've finished it. (Though I think I'd rather be listening to the tawny owls outside my window.)

[zharca]

Life, the universe and everything?
Maybe

A really esoteric bit of mathematics, the "Reimann hypothesis", has been around for ages and, if the equations are solved, appears to show a relationship between the distribution of prime numbers and Quantum mechanics - pretty much how the unvierse works.

The first two numbers of the Reimann sequence have been known for a long time, they're 1 and 2.

In 1996 a Bristol university team found the missing number - "the third moment of the Reimann zeta function".








it's 42



Gulp

[Strontium]

Sherlock has the answer, because after you look at all the probabilities, what ever is impossible must be the cause. If you believe in quantum gravity, and the many universes hypothesis, then there is a possibility, of zero, that all matter created in the big bang did not under any circumstance interact, but continue to be flung forever into space. The universe is infinite then? Or doesnt god play dice after all?

[jnb]

Originally Posted by Strontium

Sherlock has the answer, because after you look at all the probabilities, what ever is impossible must be the cause. If you believe in quantum gravity, and the many universes hypothesis, then there is a possibility, of zero, that all matter created in the big bang did not under any circumstance interact, but continue to be flung forever into space. The universe is infinite then? Or doesnt god play dice after all?

Que?

Did do you mean "there is a possibility, of zero, that all matter created in the big bang did not under any circumstance interact". I assume you mean 'contract' not interact. If so then yes there is a possibility that there is insufficient matter to reverse universal expansion. The bottom line is whether there is sufficient dark mattter to make the mass of the universe high enough to bring about that contraction. We can be fairly confident that there is insufficient visible matter but the jury remains out otherwise.

[Ukwildlifeo]

Thouigh only partly relevant a quote by einstein pops into my head "Only two things are infinite, the universe and human stupidity, and I'm not sure about the former."

Now that IS genius at work

[k9]

I've thoroughly enjoyed reading this thread. I'm glad there are so many out there who are puzzling over the same questions that keep going through my mind. k9