For all our talk on "the future now," there is one future we'd prefer to delay for the next five billion years, and that's the inevitability of our planet's destruction. Mankind's speculated on the end of the world for thousands of years, but it wasn't until recent centuries that people began attaching scientific possibilities to doomsday scenarios, instead of blaming the gods for our demise.
During the first half of the 20th century, we focused our imaginations on cosmological disasters. Billions of years from now, the sun will explode, vaporizing the Earth in a ruthless inferno. Or perhaps a swarm of asteroids would bombard our cities and crash into our oceans, resulting in a series of megatsunamis. Other scenarios included one where the Earth's surface would shrink so tightly, that its core would explode with the pressure, turning our beloved planet into just another asteroid belt. The most bizarre theory was that a rogue star would cross into our solar system, swallowing our planet within streams of deadly solar rays.
More terrifying, however, than the prospect of getting zapped by cosmic rays is the possibility that mankind will bring about its own destruction. Between the end of World War II and the early 1970s, sections of Popular Science essentially functioned as guides to surviving nuclear fallout. Nowadays, "Doomsday machine" sounds like an antiquated sci-fi myth, but type those terms into our archives and see if you don't feel unsettled by the paranoia surrounding this hypothetical weapon.
At any rate, we lived through the Cold War, although there's no telling which impending disaster will scare us quite as badly. In the meantime, click through our gallery for more creepy scenarios for how our world will end.
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.