Final answer:
In 1994, Comet Shoemaker-Levy 9 collided with Jupiter, fragmenting into pieces that generated high-altitude fireballs and left dark 'bruises' in Jupiter's stratosphere, observable from Earth.
Step-by-step explanation:
In 1994, people witnessed the spectacular collision of Comet Shoemaker-Levy 9 with the planet Jupiter. This event was highly significant because the comet broke into about 20 pieces in 1992 and these fragments were captured into an elongated orbit around Jupiter. In July 1994, these fragments crashed into Jupiter with the force of millions of megatons of TNT. The impact of each cometary fragment in the jovian atmosphere produced hot fireballs that were visible with infrared-sensitive telescopes. Moreover, the collisions resulted in dark clouds of debris settling into the stratosphere of Jupiter, creating long-lived "bruises" larger than Earth. These were clearly visible through small telescopes, allowing millions of people around the world to observe the aftermath of the impacts on Jupiter, either through telescopes or via television and online broadcasts.