65 million years ago, an asteroid hit the Earth. Apparently, this shock caused the loss of dinosaurs. Astronomer William Bottke has gone further and, analyzing the rocks between Mars and Jupiter, has come to the conclusion that that asteroid could come from another previous shock. In fact, he believes that a 170 km long asteroid 160 million years ago hit another 60 km. Part of the collision went to Earth and fell into Yucatan. That is therefore the origin of this asteroid, according to Bottke.