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So, we talked about someothing interesting in Quantum, not that we don't all the time, but, the prof introduced us to the idea (while we were talking about energy states) that our universe may not be in it's lowest energy state. That is, it could drop to the lowest energy state at any time and the whole of physics, as we know it would change, thus killing us. He said that if such a thing happened there would be a blip in the universe which would start to change and a new universe would expand at the speed of light to obliterate the old universe and everything in it. He also said that this was unlikely to happen since the universe has gone along for billions of years without this occuring, but that it was an interesting theory and a possibility. I though I'd inform you guys. What do you think? I shall explain the energy state thing once I've caught up with my reading. sweatdrop which should be next week, since my problem set is due then.

Do you mean metastable?

Alternative hypothesis--the vacuum is already decaying, but not spontaneously as in the above scenario but more analogously to the slow transition found in modern inflation, except even slower (say, second-order or higher). Possible evidence, which is far from conclusive, but present: some measurements of the fine structure constant using distant quasars (i.e., in the distant past) show a slight increase.

Yes, but I don't know enough about it to say how significant those findings were. See astro-ph/0012539, for example. All I have to say on this matter is yes, we could be living in a false vacuum right now, but even if so (and I'm not claiming it's at all likely), there is no requirement for the vacuum phase transition in your doomsday scenario to be fast.