[AGarvin]

Thanks for the lesson, but it's actually not what I meant, my fault I suppose... I acutally understand Relativity theory quite well.

Sorry Kosh, easy to misinterpret what is actually being said on forums.

I disagree that beyond the universe is a philosophical question...
My assumption that the universe is "somewhere" is no more right or wrong than your assumption that the universe is "infinite". You just finished talking about the Hubble constant and not being able to see behind it, so how do you know that the universe is infinite? So you don't belive in the "Big Bang"?

Actually, I didn't say assume or say that. What I said was that if the universe is infinite, then the "whats it expanding into" question is moot, and if it's not, then the fact that we're bound to it means we'll never be able to see outside it anyway, which is why I reckon it's a philosphical issue. The Hubble "stuff" is simply what is currently accepted theory explaining the expansion of the universe and I was merely attempting to explain it.

BTW, can you point me to any valid research/literature on the matter/energy density issue and its affect on expansion?