Vacuum Collapse

People talk a lot these days about the "zero-point energy" or "vacuum energy". You know an idea is hot when people start trying to sell you gadgets that supposedly exploit whatever the idea is, and I've seen at least a few products or services that were in some way supposed to derive some kind of power from the vacuum energy.

Unfortunately for them - at least if I understand this correctly - the vacuum energy predicted by quantum field theory is the minimum allowable energy. Since the vacuum is already at its minimum energy potential, there's no way to get any energy out of it (once the gas tank is empty, you can't get another 20 miles down the road by making the gas tank extra-empty). Virtual particle production continues apace because - again, if I understand this correctly - the Heisenberg Uncertainty Principle allows a little slop in time and energy, as though the universe doesn't mind violations of the conservation of energy if they're sufficiently temporary.

Curiously, these virtual particles can actually be promoted and turned into real particles, but you have to supply some energy to do it. Hawking radiation is one example of how you can make virtual particles real.

But what if the vacuum isn't at its minimum energy? What if it's as a false minimum? What if, by means of quantum indeterminacy, or some sort of high-energy procedure carried out by earnest physicists, the false vacuum is allowed to tunnel or collapse to a lower energy, presumably the real minimum? Physicists argue that such a collapse would completely destroy the universe in its entirety - the mathematics of such things argue that the potential energy of a new pocket of lower-energy vacuum actually increases as its volume increases, so it would propagate outward at just below the speed of light, and we'd have no warning whatsoever. Not that there would be much we could do about it even if we had advance warning. The whole universe would end up collapsing to this new minimum energy vacuum, and us along with it.

For a while people were worried that the Large Hadron Collider at CERN might do the trick, but it seems unlikely. I'm no physicist, but it seems to me that if all it took to cause a vacuum collapse was a sufficiently energetic collision, it would have happened already - cosmic rays hit the top of the Earth's atmosphere with energies many times above what the LHC can generate, and we're still here. Even more dramatic, if current theories about the Big Bang are correct, there was a time in the very early universe when energies were much higher still, at the Grand Unification level if not the Planck energy itself. And we're still here.

So I think it's safe to assume that we aren't ripe for a vacuum collapse.

But even so, when I go outside to look for falling stars, I prefer not to think about the notion of a vacuum collapse. I have enough to worry about as it is without having to fret about the possibility of the entire universe being destroyed in a catastrophic vacuum collapse, thank you very much.