I had a very interesting conversation with a physics major yesterday, something that does not often happen to me; I have a very solid orientation toward the humanities and tend to gravitate (no pun intended) to others who are also interested in the arts rather than the sciences.
Somehow we got talking about the origin and the future of the universe. You know, the Big Bang and all that. What I didn't know--or had forgotten that I knew--was that there are at least two theories about what's going to happen next.
Where we are now, after the Big Bang, everything in the universe is still expanding, right? Well, some people think that the universe at some point is going to run out of energy (I believe he said both "actual" and "potential" energy, but I didn't ask for an explanation, just nodded sagely like I knew what the heck that meant). When it runs out of energy, it is just going to stop, just freeze right in place, like a great big collection of ice cubes. That's how the universe ends. (Does time also end then? I was afraid to ask.)
In another theory, the universe also runs out of energy, but when it stops, that's not the end. After it stops, some people believe that it's going to contract, all the way back to a single point, where all the matter in the universe is concentrated into a singularity. Then what happens, they think? Another Big Bang, and the cycle begins all over again.
I realize this is nothing new to people who study this stuff. But it's been a long time since I thought about these questions, and it was pretty darn interesting to think about them yesterday.
The cyclical version makes the most sense to me. So many things are cyclical, why shouldn't the existence of the universe be cyclical, too? I wonder what version we are on now, if this has happened before and will happen again. It's almost like the universe is breathing, in and out, expand and contract.
After that we talked about the idea that some people have, that the human race should save itself by getting not only off this planet, but out of the solar system, out of the galaxy, and out of the universe, to avoid being caught in either the Big Freeze or the Big Crunch.
Maybe it's just me, but I have a little trouble wrapping my mind around the concept of "outside the universe." I was not interested in asking any follow-up questions about that, for fear that smoke would begin to come out of my ears.
But somehow my mind feels a little larger, just for having thought about it all.