Comet Shoemaker-Levy 9 did not hit Pluto, Mars, or Saturn. It collided with Jupiter.

Comet Shoemaker-Levy 9, also known as SL9, was a comet that was discovered in 1993. It was named after the astronomers Carolyn and Eugene Shoemaker and David Levy, who were the first to observe it. SL9 was an unusual comet because it had been captured by Jupiter`s gravitational pull and was orbiting the planet.

In July 1994, SL9 collided with Jupiter, creating a spectacular event that was observed by astronomers around the world. The comet had broken into multiple fragments due to tidal forces from Jupiter`s immense gravity. Over the course of several days, the fragments of SL9 sequentially impacted Jupiter`s atmosphere.

The collision of SL9 with Jupiter provided valuable insights into the dynamics and composition of both comets and giant planets. It allowed scientists to study the effects of a high-velocity impact on a planetary atmosphere and gain a better understanding of the processes involved in such events.

The impacts of the SL9 fragments on Jupiter produced massive fireballs and plumes that rose above Jupiter`s cloud tops. These features were observed using telescopes and space-based instruments, including the Hubble Space Telescope. The impact sites on Jupiter`s atmosphere were visible as dark spots, known as impact scars, which persisted for several weeks.

The event also highlighted the importance of studying comets and their potential impacts on other celestial bodies. It served as a reminder of the role that Jupiter plays in the solar system as a gravitational "vacuum cleaner," capturing and redirecting potentially dangerous objects away from inner planets like Earth.

In conclusion, Comet Shoemaker-Levy 9 collided with Jupiter, not Pluto, Mars, or Saturn. The collision provided valuable scientific data and offered a unique opportunity to study the effects of a comet impacting a giant planet`s atmosphere.