Page "Comet Shoemaker–Levy 9" Paragraph 10

The comet had apparently passed extremely close to Jupiter on July 7, 1992, just over above the planet's cloud topsa smaller distance than Jupiter's radius of, and well within the orbit of Jupiter's innermost moon Metis and the planet's Roche limit, inside which tidal forces are strong enough to disrupt a body held together only by gravity.

Although the comet had approached Jupiter closely before, the July 7 encounter seemed to be by far the closest, and the fragmentation of the comet is thought to have occurred at this time.

Each fragment of the comet was denoted by a letter of the alphabet, from " fragment A " through to " fragment W ", a practice already established from previously observed broken-up comets.