Comet Shoemaker–Levy 9 a collision was completely unprecedented, astronomers were cautious with their predictions of what the event might reveal. Anticipation grew as the predicted date for the collisions approached, and astronomers trained terrestrial telescopes on Jupiter. Several space observatories did the same, including the Hubble Space Telescope, the ROSAT X-ray-observing satellite, and significantly the "Galileo" spacecraft, then on its way to a rendezvous with Jupiter scheduled for 1995. Although the impacts took place on the side of Jupiter hidden from Earth, "Galileo", then at a distance of from the planet, was able to see the impacts as they occurred. Jupiter's rapid rotation
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