Who cares? Well, there are some implications...

Infinities get us into all sorts of trouble. If the universe were infinite in extent, then we'd face the wallpaper problem--a kind of multiple worlds situation in which, if you traveled far enough, you'd exhaust all possible configurations of particles and start repeating yourself. In an infinite universe, there'd be infinite copies of every one of us, and every possible variant of us and our lives, all being played out simultaneously and all the time.

In an infinite universe, there would be infinite energy to power the universe's expansion. So, we'd have an infinite universe, produced however from a finite point (the Big Bang) yet expanding eternally. This may still be the case, but it never seemed like a convincing narrative to me.

In an unbounded expanding universe, entropy rules.

On the other hand, in a finite but unbounded space 43 billion light years in diameter, there are a finite number of particles. There's a finite amount of energy, too, so one can ask whether the current, accelerating expansion of the universe would also be infinite. If you believe in infinities (and pixies) then sure, it could. Much more plausible to me is the idea that the expansion will also be finite.

In a finite unbounded space that is not expanding, entropy becomes a local phenomenon, not a universal principle. The universal principle becomes Poincare recurrence, which means that the universe repeats itself over long ages. To us it would appear as a cyclic universe, with multiple big bangs and big crunches.

The usual big bang/big crunch scenario has some problems--chiefly that it must be impossible to communicate information across the crunch/bang, or else we'd be surrounded by aeons-old civilizations that had figured out how to survive the cycles. Particles might recirculate, but the total amount of information in the system could increase to infinity. This is a variant of the Fermi paradox, as was pointed out by my friend Milan Cirkovic.

In a finite universe dominated by Poincare recurrence, on the other hand, the total amount of information in the system appears to be fixed. Certainly there can be progress, but there must eventually also be amnesia. There's no impediment to our civilization taking over the universe and propelling our legacy into the next cycle... but that sort of thing can't go on forever.

If the COBE data really is showing us a finite but unbounded universe, then the most likely philosophical model of where we stand may be Nietzsche's Eternal Recurrence of the Same. --No matter what happens, no matter what triumphs and tragedies occur, after near-infinite time your life will come around again, and you will live it exactly as you've done before, over and over again, time without end (time as finite, but unbounded). Many people find this a terrifying idea--the apex of nihilism--but to me it's sublime. Laurie Anderson presents a strange and ecstatic vision in "My Eyes" (from her album Strange Angels) that hints at the bittersweet experience of a finite but unbounded universe:

"So cry me a river
that leads to a road
that turns into a highway
that goes and goes
and tangles in your memories
so long
so old..."

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