Humans Could Go the Way of the Dinosaurs

Humanity lives on the edge of disaster. The celestial sphere, suspended and serene above us, has guided our species for millennia, serving as a source of stories, wonder, and navigation. But the sky is also full of threats. Asteroids, comets, and meteoroids, traveling at tens of thousands of miles per hour, completely silent and nearly invisible, crisscross the solar system and the orbit of the Earth. When the smallest ones, no bigger than a grain of sand, enter our atmosphere, we watch in delight as a shooting star flies across the heavens.

But when the larger objects strike, they unleash not marvels, but death and destruction. When an asteroid several miles wide struck off the northern coast of the Yucatan peninsula in the Gulf of Mexico 66 million years ago, the resulting impact rattled the Earth to its very iron core, uplifted crustal material and sent it raining hellfire across the globe, plunged our planet into a suffocating “impact winter,” and permanently ended the lineages of all non-avian dinosaurs.