Comet Shoemaker–Levy 9 anywhere from 30 kilopascals to a few tens of megapascals (from 0.3 to a few hundred bar), with some predictions that the comet would penetrate a layer of water and create a bluish shroud over that region of Jupiter. Astronomers did not observe large amounts of water following the collisions, and later impact studies found that fragmentation and destruction of the cometary fragments in an 'airburst' probably occurred at much higher altitudes than previously expected, with even the largest fragments being destroyed when the pressure reached , well above the expected depth of the water layer. The smaller fragments were
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