Early in Earth’s history, a killer asteroid smashed a hole in our planet about 300 miles (500 kilometers) wide, which is greater than the driving distance between Washington and New York City, a new study says. The space rock set off a cycle of destruction that sounds like your worst nightmares. That one reported collision … Continue reading "Asteroid That Dwarfed Dinosaur-Killer Punched Earth 3 Billion Years Ago, Study Says"