Hopefully, there weren't any angry Libyans in Twin City Plaza

Yes I know. Because that's pretty much the 'science' theory behind the old 90s TV Show Sliders, which is about the multiuniverse theory. I refer to this as a parallel universe, or the "slice" theory (slices of life)

Because right now in a parallel universe, I am sitting here writing this reply on a Dell computer because I opted for the Dell XPS system I was looking at instead of the HP Z system I have instead when I bought a new computer a few months ago.

OR right now in a parallel universe, I'm writing this post, but it's in German because that Axis won WWII instead of the Allies.

OR right now in a parallel universe, a younger version of me is writing this reply because instead of being born in the 70s, the birth control was taken, and my parents didn't have another child until 1983 in that universe (I was a product of a hidden birth control pill via my father)

OR right now in a parallel universe, I'm not writing a reply because 5 years ago I 'missed' the link I saw on facebook that directed me to the site, so that version of me has no idea what Universal Hub is.

Something like that. It's an interesting twist.

But I was primarily talking about the Back to the Future Universe (as fiction)... (go read that link, your head will spin)

But thanks for the brain twist this morning...

Technically speaking, we do know that the Universe goes on forever.

No. Not by our current understanding of the observable universe. The universe, is "only" 91×10^9 light years across, and although extremely old (our best data says about 13.8 billion years), it does evolve. Conditions now are quite different than they were in the past. And conditions in the future will also be very different. Just how different is still something we've not enough data to determine exactly. But every model with any data to support it indicates that this universe is not the 'eternal machine' you're implying. It'll end, either by collapsing back into a point of infinite density, or by cooling off to a uniformly diffuse and cold expanse. No one's found any new 'stuff' pouring in from somewhere else to keep the wheel turning forever. And we've looked - and continue to look.

Now, perhaps there's a quantum 'multiverse' of alternate universes, differing from ours so slightly that only the details of personal lives of creatures like us divide them (ala cybah's Sliders ref). In some ways, it's a pleasing conceit, but unfortunately there isn't any evidence at this point that this is how things work.

And believe me, lots of cosmologists/mathematicians (especially the ones who think string theory is cool) have been trying to figure out a way to see if this is true. At this point, no one even has a theoretical experiment that could show this.

Or perhaps the universe will collapse and re-"Big Bang". We've not nailed down exactly what is going on with strange matter and strange energy, and the ultimate nature of these will determine if we're just one of an unending chorus of cosmic flowerings. But even if this is true, this universe isn't going to just reverse and repeat - the very nature of the mass-energy that collapses in the last seconds will be completely different than what exploded out in the first few. And no matter - or even information - about the Universe will survive that final infinite 'crunch'.

So sorry, it looks like this is the only universe you and I or anything like us will ever know, and it's just going to happen once.

Make the best of it now. No do-overs.

These thoughts brought to you courtesy of an MIT-trained planetary scientist on his 50th birthday.