There was a giant space rock about 9 miles wide.  In an explosion one billion times more powerful than the atomic bomb blast at Hiroshima, the asteroid smashed into Mexico.  In a matter of days, more than half of the species on earth were wiped out including the dinosaurs. This happened around 65 million years ago.

Read the original article here:   http://www.sciencedaily.com/releases/2010/03/100304142242.htm