Droplets of glass dug up in New Jersey and from the Atlantic seabed indicate a comet or some other extraterrestrial object may have smacked Earth 56 million years ago, roughly 10 million years after the asteroid impact that doomed the dinosaurs.
Scientists said on Thursday the collision may have triggered a particularly warm, ice-free period on Earth when important mammalian groups, including the primate lineage that led to humans, appeared for the first time.
