Encounter with a String of Pearls

For six days in July 1994, fiery fragments of Comet Shoemaker-Levy 9 rained down on Jupiter, the first collision of two solar system bodies ever witnessed. Measuring as much as one and a quarter miles wide, the fragments slammed into Jupiter's atmosphere at more than 30 miles per second. The fragments all struck Jupiter from the south as the planet rotated beneath them, leaving scars in the atmosphere that lasted for weeks. Had the fragments struck a solid surface, Jupiter would be sporting a vast necklace of craters, an extended version of a chain of craters on its moon Callisto (above). At one impact site in the Jovian atmosphere, one of the fragments left a dark thick ring the size of Earth (opposite)