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.
Astronomical symbols Ω (capital omega), which was originally a typographical substitute for the astronomical symbol. The symbols for aspects first appear in Byzantine codices. Of the symbols for the five Ptolemaic aspects, only the three displayed here—for conjunction, opposition, and quadrature—are used in astronomy. Symbols for a comet (☄) and a star () have been used in published astronomical observations of comets. In tables of these observations, ☄ stood for the comet being discussed and for the star of comparison relative to which measurements of the comet's position were made. Astronomical symbols Astronomical symbols are abstract pictorial symbols used to represent astronomical