Distant space collision meant doom for dinosaurs
WASHINGTON (Reuters) - A collision 160 million years ago of two asteroids orbiting between Mars and Jupiter sent many big rock chunks hurtling toward Earth, including the one that zapped the dinosaurs, scientists said on Wednesday. Their research offered an explanation for the cause of one of the most momentous events in the history of life on Earth -- a six-mile-wide (10-km-wide) meteorite striking Mexico's Yucatan peninsula 65 million years ago. That catastrophe eliminated the dinosaurs, which had flourished for about 165 million years, and many other life forms, and paved the way for mammals to dominate the Earth and the eventual rise of humankind, many scientists believe. The impact is thought to have triggered a worldwide environmental cataclysm, expelling vast quantities of rock and dust into the sky, unleashing giant tsunamis, sparking global wildfires and leaving Earth shrouded in darkness for years. U.S. and Czech researchers used computer simulations to calculate that the...