Is it really so bad if a vacuum bubble wipes out the universe?

There have been a number of articles quoting scientists, for example, Dr Joseph Lykken of the Fermi National Accelerator Laboratory, who are looking into the possibility that we're living in a universe pervaded by an "unstable vacuum".  These scientists say they're still crunching the numbers, but it's possible that the 126 GeV/c^2 mass of the Higgs boson (I just threw the c^2 in there to show I can get the units right) gives rise to the possibility under the Standard Model that our universe, most of which appears to be at vacuum state, is in fact a "false vacuum".

The best analogy that explains this is a glass of super-heated water, which is a state of liquid water that can be achieved in a standard microwave oven in which the temperature of the water exceeds the ordinary boiling point, but nothing has nucleated a bubble of steam (yet).  Then, some event happens, such as a sound wave, perhaps, that jolts the system into forming a bubble of water vapor.  Water in this bubble is at a lower energy state, and systems "like" to roll downhill, so to speak, so the bubble expands, and soon takes over the whole container.

So is our universe at a "false vacuum"? If so, then with some possibly nonzero probability, p, a bubble of true vacuum may appear somewhere in the universe, and expand outwards at the speed of light, gobbling up what *we* think of as the universe as it expands.  For all we know, such a bubble may have already appeared at a point 5 billion light years from earth, but we don't know it yet, because the bubble began only 4.9 billion light years ago.

Now, here's where it gets interesting.

Consider the case that a growing bubble of true (or truer) vacuum can wipe us out in an instant, and that it can happen any time -- but at random and with very very small, but, importantly: nonzero (and non-one) -- probability.  And then combine this with the "many worlds" interpretation of quantum mechanics that says that *both* possible outcomes of any quantum event (and by extension, *all* outcomes of any series of quantum events) exist, but each in their own parallel universe.

So did a vacuum bubble wipe us out yesterday?  Almost* certainly!  I can say that because the probability of it happening in any given nonzero period of time is nonzero.  But it didn't happen in *our* universe.  I can say that, because if it happened in our universe, we wouldn't be here to report on it. (I wrote "almost*" because if there are a finite number of "pocket universes" in the multiverse, then it's possible for an event with nonzero probability to still not occur in any one of the pocket universes.  But if the number of pocket universes is infinite, then the "almost*" can be deleted.)

So, to me, the interesting part is the consideration of a proposal that two things are true:  1. the nonzero probability of our known universe being wiped out any give day, and  2. the many worlds interpretation of quantum mechanics -- that there is *no way to disprove that proposal* (in our pocket universe).

The probability that the universe will end tomorrow doesn't even have to be very low for this proposal to be unfalsifiable!  Consider, for example, the case that on any given day there is a 10% probability that the universe will end, and that the many worlds interpretation of quantum mechanics is true.  We know from that interpretation that a probability of 10% means that in 10% of the "pocket universes" the event happened, and in the other 90% of pocket universes, the event didn't happen.  So the only instance of "me" that survives is the one in those pocket universes in which the event didn't happen.  And that's the case, day after day!

So, you see, the universe could be extremely unstable, but as long as these two things are true:  nonzero (and non-one) probability of instability on any given day, and many worlds, then we (and by "we" I mean "I") will never know it!