In a catastrophic instant some 66 million years ago, the course of life on Earth was forever changed. A six-mile-wide space rock slammed into the coast of Mexico’s Yucatán Peninsula—and it kicked off a global cataclysm. The towering tsunamis that followed crashed on shores for thousands of miles. Wildfires raced across vast swaths of land. And the vaporization of rock along the seafloor unleashed gasses that sent the climate into wild swings—all of which led to the extinction of some 75 percent of all species, including all non-avian dinosaurs.
But this might not be the whole story. Buried under layers of sand on the coast of West Africa are hints that the giant space rock might not have been alone.
Researchers discovered a possible crater that spans some 5.3 miles wide, revealed in seismic surveys of the seafloor, according to a new study published in Science Advances. The crater, dubbed Nadir after a submarine volcano nearby, appears to have been carved by the impact of a space rock at least a quarter of a mile wide—and it may have formed around the same time as the Chicxulub crater, the expansive scar in Earth’s surface from the dinosaur-killing asteroid.