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Thirty years ago, Comet Shoemaker-Levy 9 collided with Jupiter, marking a historic moment in astronomy. This collision gave scientists a first-of-its-kind direct observation of an extraterrestrial collision within our Solar System, providing important information regarding Jupiter\u2019s atmosphere and its role in protecting the inner planets from cosmic debris.<\/strong><\/p>\n Thirty years ago, Comet Shoemaker-Levy 9 (SL9) collided with Jupiter. This occurrence gave scientists and researchers a first-of-its-kind direct observation of an extraterrestrial collision within our Solar System, providing important information regarding Jupiter\u2019s atmosphere and its role in protecting the inner planets from cosmic debris.<\/p>\n Astronomers Carolyn and Eugene Shoemaker, along with David Levy, found SL9 on March 24, 1993, using the Palomar Observatory\u2019s 46 cm (18 inches) Schmidt telescope. Unlike ordinary comets that circle the Sun, SL9 was captured in orbit around Jupiter. Researchers inferred that the comet was pulled into Jupiter\u2019s orbit by its gravitational force some 70 years ago around the 1920s.<\/p>\n Dr. Heidi Hammel who led visible-light observations of the comet with NASA\u2019s Hubble Space Telescope and is currently serving as the Vice President of Science at the Association of Universities for Research in Astronomy (AURA), explained the unique nature of SL9, \u201cShoemaker-Levy 9 was a comet that was discovered by Eugene and Carolyn Shoemaker and David Levy, which is why it\u2019s called Shoemaker-Levy 9. It was the ninth comet that the team had found. What was unusual about Shoemaker-Levy 9 was that it was in orbit around Jupiter.\u201d<\/p>\n In July 1992, SL9 passed within Jupiter\u2019s Roche limit which is the distance between one celestial body and another celestial body, held together by gravity where the second body will disintegrate because the first body\u2019s tidal forces surpass the second body\u2019s self-gravitation. This proximity caused the comet to fragment into multiple pieces, setting the stage for its eventual collision with Jupiter.<\/p>\n Between July 16 and 22, 21 SL9 fragments collided in the southern hemisphere of Jupiter at a speed of 60 km\/s (50 miles\/s). These collisions caused dark indentations in Jupiter\u2019s atmosphere that became more evident than the Great Red Spot of Jupiter which lasted several months. Dr. Hammel explained the sequence of events, \u201cIt was a week-long occurrence. It took that long for all of the fragments of this fractured comet to strike Jupiter. It emitted a gigantic plume of material that extended for thousands of kilometres over Jupiter\u2019s cloud tops. It took around 20 minutes to rise and then collapsed.\u201d<\/p>\n The first impact from Fragment A took place on July 16, 1992 resulting in a fireball with a peak temperature of approximately 24 000 K. The plume from this fireball rose more than 3 000 km (1 864 miles) into Jupiter\u2019s clouds, as witnessed by the Hubble Space Telescope. Over the next 6 days, 21 impacts were reported, the most devastating being from Fragment G, which released energy equivalent to 6 million megatons of TNT.<\/p>\n \n\n