Sixty-six million years ago, a catastrophic asteroid impact wiped out 75% of Earth’s species, bringing an abrupt end to the reign of the nonavian dinosaurs. The 9-mile-wide (15 km) space rock struck ...

Imagine a world where dinosaurs and humans coexist. A new study is asking this question, as there may just be proof that had an asteroid not hit Earth and caused one of the great extinctions, ...