Yet it can be hard to figure out what exactly the Doomsday Clock is forecasting, because the Bulletin doesn’t countenance only nuclear conflict anymore. The scientists and security experts of the Bulletin now look to four different risk areas when they make their report. The biggest of these remain, first, the possibility of a major conflict between nuclear states, and, second, out-of-control climate change. But the Bulletin also follows the risks of a civilian nuclear-power disaster, especially around waste storage, and what it calls “emerging technologies,” like genetically modified pandemics or destructive artificial intelligence.

“What connects all of those four? For us, it’s about existential threat—the things that can end life on this planet as we know it,” says Rachel Bronson, the executive director of the Bulletin.

She explained why the clock now includes more than the nuclear threat:“For a moment in time each year, the bulletin is able to prompt this global conversation on these truly existential issues that are really hard to discuss. It gives us a benchmark for where a set of leading experts are,” she told me Wednesday. “We were trending in the U.S. yesterday, we were top ten, and that blew me away. That’s Jimmy Fallon territory.”

It’s true. More than 48 hours after its announcement ended, the Bulletin was still trending on Facebook and Twitter—and this wasn’t even a year when they moved the clock hand. But speaking to Bronson, and reading the Bulletin of Atomic Scientists’s annual briefing to accompany the Doomsday Clock announcement, I had the same thought about this being a rare opportunity to discuss these existential issues—though I’m not sure whether I shared Bronson’s positivity.

Very few organizations talk regularly about the destructiveness of nuclear weapons anymore, and those that do can can seem mysterious. It’s only them, and the deterrent power of the weapons themselves, that stand between us and fiery, anguished deaths. Yet when you look into the process of setting the clock, it seems unequal to the task: It’s 10 or 20 people, of exceptional but not supernatural ability, with well-rounded but not omniscient expertise, sitting in a room for a day and doing the best they can to communicate disaster.

* * *

Sitting in a room is more or less how these decisions get made. Despite science being in the Bulletin’s name, its methods are more Socratic than anything else. Every year, the ten scientists and security experts on its board gather for a one-day discussion where they review what worried them last year and anticipate new concerns. There are no minute-hand-divining devices and no instability-predicting supercomputers: Just a bunch of experienced adults, trying to come to a consensus about how bad things have gotten.

Bronson told me that the board members “know coming into it what the big events of the year were—positive and negative—and they know what they’re concerned about for years going forward. And it becomes a professional discussion. Do their colleagues see it the same way? Who sees it differently and why?”