Comet Shoemaker–Levy 9 A of the nucleus entered Jupiter's southern hemisphere at a speed of about . Instruments on "Galileo" detected a fireball that reached a peak temperature of about , compared to the typical Jovian cloudtop temperature of about , before expanding and cooling rapidly to about after 40 seconds. The plume from the fireball quickly reached a height of over . A few minutes after the impact fireball was detected, "Galileo" measured renewed heating, probably due to ejected material falling back onto the planet. Earth-based observers detected the fireball rising over the limb of the planet shortly after the initial impact.
Naming of comets the past, when multiple comets were discovered by the same individual, group of individuals, or team, the comets' names were distinguished by adding a numeral to the discoverers' names (but only for periodic comets); thus Comets Shoemaker–Levy 1 to 9 (discovered by Carolyn Shoemaker, Eugene Shoemaker & David Levy). Today, the large numbers of comets discovered by some instruments makes this system impractical, and no attempt is made to ensure that each comet is given a unique name. Instead, the comets' systematic designations are used to avoid confusion. Until 1994, comets were first given a provisional designation consisting of the