Editing Galileo project (section)

=== Comet Shoemaker–Levy 9 ===
{{main|Comet Shoemaker–Levy 9}}
[[File:SL9ImpactGalileo.jpg|thumb|right|Four images of Jupiter and [[Comet Shoemaker–Levy 9]] in visible light taken by ''Galileo'' at {{frac|2|1|3}}-second intervals from a distance of {{convert|238|e6km|e6mi|sp=us|abbr=off}} |alt=refer to caption]]
''Galileo''{{'s}} prime mission was a two-year study of the Jovian system, but on March 26, 1993, while it was en route, astronomers [[Carolyn S. Shoemaker]], [[Eugene Merle Shoemaker|Eugene M. Shoemaker]] and [[David H. Levy]] discovered fragments of a comet orbiting Jupiter, the remains of a comet that had passed within Jupiter's [[Roche limit]] and had been torn apart by [[tidal force]]s. It was named [[Comet Shoemaker–Levy 9]]. Calculations indicated that it would crash into the planet sometime between July 16 and 24, 1994. Although ''Galileo'' was still {{convert|238|e6km|sp=us|abbr=off}} away, Jupiter was 66 pixels wide in its camera, and it was perfectly positioned to observe this event. Terrestrial telescopes had to wait to see the [[impact event]] sites as they rotated into view because it would occur on Jupiter's night side.{{sfn|Meltzer|2007|pp=188–189}}{{sfn|Harland|2000|p=80}}

Instead of burning up in Jupiter's atmosphere as expected, the first of the 21 comet fragments struck the planet at around {{convert|320000|km/h|sp=us}} and exploded with a fireball {{convert|3000|km|sp=us}} high, easily discernible to Earth-based telescopes even though it was on the night side of the planet. The impact left a series of dark scars on the planet, some two or three times as large as the Earth, that persisted for weeks. When ''Galileo'' observed an impact in ultraviolet light, the fireballs lasted for about ten seconds, but in the infrared they persisted for 90 seconds or more. When a fragment hit the planet, it increased Jupiter's overall brightness by about 20 percent. The NIMS observed one fragment create a fireball {{convert|7|km|sp=us}} in diameter that burned with a temperature of {{convert|8000|K|C F|sigfig=2}}, which was hotter than the surface of the Sun.{{sfn|Meltzer|2007|pp=190–191}}{{sfn|Harland|2000|pp=82–83}}