In a recent New Yorker article, the nuclear historian Alex Wellerstein collected testimony from several people who saw, firsthand, the flash from the first successful detonation of the atomic bomb, at the infamous Trinity Test, on July 16, 1945.
Wellerstein has a writer’s feel for quotes and anecdotes. According to one general, the flash was a “golden, purple, violet, gray, and blue light” that illuminated “every peak, crevasse, and ridge” of a nearby mountain range, “with a clarity and beauty that cannot be described.” Wellerstein notes that several eyewitnesses described Trinity’s light as “cosmic.” This was apropos, he says, for nowhere else, “except in the interiors of stars do temperatures reach into the tens of millions of degrees,” as they do during a nuclear explosion.
A team of astronomers recently tried to determine whether Trinity’s light might be cosmic in a different sense. The Trinity test involved only one explosion. But if there were many more explosions, involving many more nuclear weapons, it might generate enough heat and light to be seen from nearby stars, or from the deeper reaches of our galaxy—so long as someone out there was looking.
And so, the thinking goes, maybe we should be looking. If every intelligent species eventually stumbles on nuclear technology, and not all of them manage it well, then it might be possible to spot an apocalypse in the heavens. Or several.