http://kuow.org en Fresh Clues In Dinosaur Whodunit Point To Asteroid http://kuow.org/post/fresh-clues-dinosaur-whodunit-point-asteroid Some 66 million years ago, about 75 percent of species on Earth disappeared. It wasn't just dinosaurs but most large mammals, fish, birds and plankton. Scientists have known this for a long time just from looking at the fossil record. If you dig deep enough, you find lots of dinosaur bones. And then a few layers up, they're gone.<p>But scientists couldn't figure out exactly what had caused this phenomenon. Of course, there were lots of theories.<p>"Some of them are pretty wacky," says <a href="http://www.bio.sdsu.edu/faculty/archibald.html/">J. Thu, 07 Feb 2013 21:49:00 +0000 editor 7876 at http://kuow.org Fresh Clues In Dinosaur Whodunit Point To Asteroid