On this day, 31 years ago, July 16, 1994 (June 8, 1994, the comet Jupiter collided. Photo taken by the Hubble Space Telescope on May 17, 1994 Comet Shoemaker-Levy9 (SL9, D/1993F2) is a comet that collided with Jupiter in mid-to-late July 1994. It is also the first time that people can directly observe a celestial impact event in the solar system. It has attracted the attention of many mainstream media around the world and attracted observations from astronomers around the world. Through this incident, people can know more about Jupiter and its atmosphere, and Jupiter plays the role of "scavenger" in the inner solar system, using its strong gravity to clean up "space junk." The comet was jointly discovered by American astronomers Eugene and Carolyn Shoemaker and astronomer David H.Levy at the Paloma Observatory in California on March 24, 1993. It was the ninth comet they discovered, so it was named after the three names in accordance with the International Star Naming Rules. Originally, the comet left the asteroid belt on the outer side of the solar system and entered the solar system as a periodic comet. According to computer orbit calculations, it was divided into 21 small fragments due to strong gravity when it was 40,000 kilometers away from Jupiter's surface on July 8, 1992. At 20:15 GMT on July 16, 1994, it gradually entered Jupiter's atmosphere at a speed of 210,000 kilometers per hour and crashed into Jupiter's southern hemisphere. Formed the astronomical spectacle of a comet crashing into Jupiter. Among the impact powers of multiple fragments, fragment G is the most powerful. It hit Jupiter at 07:32 (UTC) on July 18, with a power of 6 trillion tons of TNT (equivalent to 750 times the total global nuclear weapons stockpile), creating a scar longer than the diameter of the Earth. Because the place of occurrence is very far away, it has no impact on the earth. Comments: Comets and other celestial bodies are a great threat to the earth, and mankind must always pay attention to it.