That the rock ended up so far away from ground zero is evidence, according to Kyte, that it came from an asteroid and not a comet, which would have hit the Earth at such high speed that it would have been vaporized. Don't expect the mystery of What Killed The Dinosaurs to be resolved yet, however. The report still awaits further review.
UCLA geochemist Frank Kyte says he found the bullet that had the dinosaurs' name on it. Scientists generally believe something bashed a 120-mile-wide crater into Mexico's Yucatan Peninsula 65 million years ago, causing the extinction of the big lizards and 70 percent of all life. But so far no one has shown convincing evidence of what that object actually was. In a report to Nature, Kyte says an asteroid did the dinos in. The proof: a pea-size fragment plucked from a 65 million-year-old sedimentary layer on the floor of the North Pacific, some 5,400 miles away from the Yucatan. The rock contains concentrations of metals such as nickel and iridium that are clearly extraterrestrial, and its arrival on Earth coincides with what biologists like to term the "extinction-level event."