Researchers say they have discovered new details about the day an asteroid hit Earth and killed off the dinosaurs. Scientists believe the asteroid struck the Earth about 65 million years ago near what is today Mexico’s Yucatn Peninsula. The force of the massive asteroid crash is estimated to have been equal to the strength of about 10 billion nuclear bombs. The U.S. Space Agency NASA has estimated the strike created a huge crater about 180 kilometers wide and 900 meters deep. The event is believed to have caused widespread wildfires, earthquakes and ocean waves, or tsunamis. It also released chemicals into the atmosphere, leading to severe cooling that harmed many living things.