Comet Shoemaker–Levy 9 comet was later observed as a series of fragments ranging up to in diameter. These fragments collided with Jupiter's southern hemisphere between July 16 and 22, 1994 at a speed of approximately (Jupiter's escape velocity) or . The prominent scars from the impacts were more easily visible than the Great Red Spot and persisted for many months. While conducting a program of observations designed to uncover near-Earth objects, the Shoemakers and Levy discovered Comet Shoemaker–Levy 9 on the night of March 24, 1993 in a photograph taken with the Schmidt telescope at the Palomar Observatory in California. The comet was
Eugene Merle Shoemaker Institute in 1965. Coming to Caltech in 1969, he started a systematic search for Earth orbit-crossing asteroids, which resulted in the discovery of several families of such asteroids, including the Apollo asteroids. Shoemaker advanced the idea that sudden geologic changes can arise from asteroid strikes and that asteroid strikes are common over geologic time periods. Previously, astroblemes were thought to be remnants of extinct volcanoes — even on the Moon. In 1993, he co-discovered Comet Shoemaker–Levy 9 using the 18-inch Schmidt camera at Palomar Observatory. This comet was unique in that it provided the first opportunity to observe the planetary