Cretaceous–Paleogene boundary had been that no documented crater matched the event. This was not a lethal blow to the theory; while the crater resulting from the impact would have been larger than in diameter, Earth's geological processes hide or destroy craters over time. The Chicxulub crater (; ) is an impact crater buried underneath the Yucatán Peninsula in Mexico. Its center is located near the town of Chicxulub, after which the crater is named. It was formed by a large asteroid or comet about in diameter, the Chicxulub impactor, striking the Earth. The date of the impact coincides precisely with the Cretaceous–Paleogene
Impact crater According to David H. Levy, Gene "saw the craters on the Moon as logical impact sites that were formed not gradually, in eons, but explosively, in seconds." For his Ph.D. degree at Princeton (1960), under the guidance of Harry Hammond Hess, Shoemaker studied the impact dynamics of Barringer Meteor Crater. Shoemaker noted Meteor Crater had the same form and structure as two explosion craters created from atomic bomb tests at the Nevada Test Site, notably Jangle U in 1951 and Teapot Ess in 1955. In 1960, Edward C. T. Chao and Shoemaker identified (coesite) at Meteor Crater, proving the crater