Today’s Wall Street Journal reports the latest findings in the case of the extinction of the dinosaurs. Sharon Begley’s story is “Asteroid cleared in dinosaurs’ death.” Here’s the gist:
Suspicious that a 65-million-year-old asteroid had been falsely convicted of mass murder, a team of geoscientists went back to the scene of the crime, a submerged crater more than 110 miles wide just off Mexico’s Yucatan peninsula long thought to be the remnants of the impact that doomed the dinosaurs.
After more than two years of gumshoe work, the scientific sleuths have reached a controversial conclusion: The asteroid that formed the Chicxulub crater crashed to Earth 300,000 years before the dinosaurs and many other species died out, the researchers reported Monday in the online edition of Proceedings of the National Academy of Sciences.
That means the space rock was framed. And the real culprit is still at large.
The findings by a team led by Gerta Keller, a 58-year-old Princeton University geoscientist, already are reopening the debate over dinosaurs’ extinction, since many researchers believe their demise was triggered by a single, cataclysmic asteroid hit. It now appears that dinosaurs were instead wiped out over a longer period of time by the cumulative effect of an even larger asteroid, as yet undiscovered, and massive volcano eruptions around the world.
Here’s the timeline that accompanies the Journal story, based on the work of Dartmouth’s Charles Officer and Princeton’s Gerta Kelly: