you aren't going to get a better explanation than "because it can"
we don't and very probably will never know what is outside the universe. Nor does it have any bearing on anything.
( Vipros. clever got me this far, then tricky got me in, Wed 11 Aug 2010, 15:48, 2 replies, latest was 16 years ago)

it must be God
your logic and science have turned me to religion! I hope you are happy you fucks.
( SteveFrench Cardio is for homo's. do you even lift bro?, Wed 11 Aug 2010, 15:52, Reply)

this whole thread is making my brain cells bang into each other
like when you're hungover and walk into doorframes
( Kitty v1.0 desperately naive, Wed 11 Aug 2010, 16:05, Reply)

"finite but unbounded"
At the risk of sounding like Doc Brown, it's difficult for us to think sufficiently-dimensionally. Here's the analogy I first heard.

Imagine beings who can only perceive two dimensions, living on the surface of a large sphere, so to them the world appears flat, but however far they go, they never fall off the edge. Strange.

We, on the other hand, are able to appreciate the fact that there's a third dimension. So we know what's really going on.

Just add a dimension or two, and you have us, and our appreciation of the Universe.

I think. (Though it makes my brain hurt.)
(BrianHequator was stretching owls, on, or around, Wed 11 Aug 2010, 16:08, Reply)

I read that explanation again very recently
it's a good one.
( Vipros. clever got me this far, then tricky got me in, Wed 11 Aug 2010, 16:14, Reply)

I think I'm going to be sick
I just can't handle stuff like that. I think I might be inbred or something.
( Kitty v1.0 desperately naive, Wed 11 Aug 2010, 16:15, Reply)