在1994年7月16.826～22.330日(世界时),苏梅克—列维9号彗星(SL—9)的21个亚核(最大的直径为2公里左右)以60公里/秒的速度,接近45°的倾角连珠般撞向木星。这是人类历史上第一次精确预测(精确率±7分钟),并在陆地和空中全过程观测的千载难逢的彗星撞击行星事件。尽管由于SL—9撞向木星的预定点是在背向地球的侧面南端,在地平面上可观测的时间只有3小时,当21个亚核继续不断撞向木星时,各地能观测到的碰撞事件均不超过5个,但由于木星的自转周期小于10小时,这就使虽然不能直接观测的碰撞所产生的木星云端的变化全被观测到了。在7月15日至22日及前后几天地球上几乎所有的望远镜都对准了木星,工作在从紫外到射电的所有波段。在空间进行观测的有行星际飞行器伽利略号、旅行者2号、尤利西斯号、哈勃空间望远镜及位于同步自转轨道上的国际紫外探险者。伽利略号宇宙探测器当时离开木星距离为1.5天文单位(1天文单位=日地平均距 In July 1994 (16.826 to 22.330) (World Time), the 21 sub-nucleuses (the largest diameter of about 2 km) of the comet Shoemaker-Levy 9 (SL-9) had a speed of 60 km/s. The dip close to 45° rammed into Jupiter. This is the first accurate prediction in human history (with a precision of ±7 minutes) and the rare event of a comet impacting the planet as observed throughout the land and air. Although the expected point of the SL-9 ramming into Jupiter is on the southern side of the side facing away from the Earth, the observable time on the ground plane is only 3 hours. When 21 subnuclears continue to collide with Jupiter, collisions can be observed everywhere. There are no more than five incidents, but since Jupiter’s rotation period is less than 10 hours, all the changes in Jupiter’s cloud that were not directly observed by the collision were observed. Almost all of the telescopes on Earth were directed at Jupiter from July 15 to July 22 and around the same time, working in all wavelength bands from the ultraviolet to the radio. The interplanetary aircraft Galileo, Voyager 2, Ulysses, Hubble Space Telescope and international UV explorers on synchronous rotation orbit were observed in space. The Galileo space probe left Jupiter at that time with a distance of 1.5 astronomical units (1 astronomical unit = average distance between the sun and the sun)