Stephen Hawking wants humanity to outlive us by as long as possible, and this has put his mind—occasionally—on existential threats to humanity. Some people, like CNET’s Chris Matyszczyk, ridicule him for it; others, like my colleague Martin J. Clemens, rightly point out when people make more out of what he says than they should. But what’s clear is that he does have some concerns in this area, and they’re both constructive and well-founded.
But—contrary to dozens of sensational headlines—Hawking's cheeky thought exercise about the possible destructive potential of the Higgs boson, which will be published in the preface to next month’s Starmus Festival anthology, doesn’t describe a serious existential threat. If anything, it's closer to the old line about how you should never put anything smaller than your elbow in your ear:
"The Higgs potential has the worrisome feature that it might become metastable at energies above 100bn gigaelectronvolts (GeV). This could mean that the universe could undergo catastrophic vacuum decay, with a bubble of the true vacuum expanding at the speed of light. This could happen at any time and we wouldn't see it coming, [but] …[a] particle accelerator that reaches 100bn GeV would be larger than Earth, and is unlikely to be funded in the present economic climate."
History suggests that if we ever get around to building larger-than-Earth supercolliders, we’ll find all sorts of dangerous ways to use them (and even more dangerous ways to use the technologies we discover between now and then). But the subtext of Hawking’s comment is that the modest little contraptions we can build now aren’t anywhere near powerful enough to tear a hole in the fabric of reality.
And it’s not even a given that anything ever could; Hawking lost a $100 bet when the Higgs boson was discovered, and would no doubt be the first to say that we don’t know for certain how it might behave in a metastable state, or even whether it would be possible to induce one. Stephen Hawking is a scientist. When he says “might,” he really means “might."