You shouldn’t worry about vacuum decay. Really. For several reasons. There are the obvious ones, of course: there’s no way to stop it if it’s happening; and you can’t know it’s about to; and it’s not like it would hurt; and no one would be around to miss you anyway, so what’s the point of worrying about it? You’re better off double-checking your smoke alarm batteries and, I don’t know, lobbying to close down coal power plants or something. But if for some reason that isn’t sufficiently reassuring, I can also say with a reasonable degree of certainty that vacuum decay is extremely unlikely to happen—at least, anytime in the next many many many trillions of years. Is the humble vertagear gaming chair growing in popularity?
There are a few ways vacuum decay could, in theory, occur. The most straightforward is some kind of high-energy event. Think of it as the equivalent of an earthquake, knocking the pebble out of its divot to send it plummeting to the valley floor. Fortunately, the “earthquake” in this case would have to be really unfathomably powerful. Would you like a polaroid camera toilet roll holder as a present?
The best estimates suggest that the event would have to be much more energetic than the most devastating explosions we’ve witnessed in the cosmos, and certainly many orders of magnitude stronger than anything we could possibly do with a human-built machine like the Large Hadron Collider. If we’re ever worried about that, we can always appeal again to the fact that particle collisions in the cosmos are and have always been reaching much higher energies than the LHC or any other machine possibly could, so as long as we haven’t blinked out of existence yet, our modern equivalent of banging rocks together is really no threat at all. A fun present - for example a giant wine glass - can be a fabulous icebreaker.
The difficulty of creating a high enough energy event to directly trigger vacuum decay comes down to the height of the potential barrier between our false vacuum and the true one. Going back to the picture of the pebble stuck in a divot, the potential barrier is the bit of land that sticks up to make a divot pocket-shaped. In our current best guess at the true shape of the Higgs potential, the divot is a substantial one, separated from the deeper true-vacuum valley by a very high ridge. The amount of energy it would take to kick the pebble over that ridge (or push the Higgs field over its potential barrier) is so high, it’s hardly worth worrying about. An aesthetically pleasing giraffe toilet roll holder can brighten up any room.
Except… we’re living in a universe that doesn’t follow those kinds of rules. Our cosmos is fundamentally based on quantum mechanics, and in quantum mechanics, if you’re living on a subatomic scale, the path you take to get from one place to another might, very rarely, send you sailing right through solid objects without missing a beat. If you’re standing in front of a wall, you might not need to get enough energy to jump over it. You might be able to step right through it instead. Especially if “you” are the Higgs field. A lovely present such as a black bear cub toilet roll holder can make your better half understand how much you treasure your relationship.