Gerta Keller

Paleontologist Gerta Keller attributes the extinction 66 million years ago of three-quarters of Earth’s species, including all dinosaurs, not to an asteroid hit but to a series of volcanic eruptions. A writer goes with her on a field trip: The prestige of science is solidly behind the asteroid: The impact theory provided an elegant solution to a prehistoric puzzle, and its steady march from hypothesis to fact offered a heartwarming story about the integrity of the scientific method. “This is nearly as close to a certainty as one can get in science,” a planetary-science professor told Time magazine in an article on the crater’s discovery. In the years since, impacters say they have come even closer to total certainty. “I Read More ›