Important eventsBack

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 0.4 m (1.3 ft) Schmidt telescope at the Palomar Observatory in California. The comet was thus a serendipitous discovery, but one that quickly overshadowed the results from their main observing program.

Comet Shoemaker–Levy 9 was the ninth periodic comet (a comet whose orbital period is 200 years or less) discovered by the Shoemakers and Levy, hence its name. It was their eleventh comet discovery overall including their discovery of two non-periodic comets, which use a different nomenclature. The discovery was announced in IAU Circular 5725 on March 27, 1993.

The discovery image gave the first hint that comet Shoemaker–Levy 9 was an unusual comet, as it appeared to show multiple nuclei in an elongated region about 50 arcseconds long and 10 arcseconds wide. Brian Marsden of the Central Bureau for Astronomical Telegrams noted that the comet lay only about 4 degrees from Jupiter as seen from Earth, and that while this could of course be a line of sight effect, its apparent motion in the sky suggested that it was physically close to the giant planet. Because of this, he suggested that the Shoemakers and David Levy had discovered the fragments of a comet that had been disrupted by Jupiter's gravity.