Astronomers say Jupiter has apparently been struck by an object, possibly a comet. Images taken by NASA early Monday show a scar in the atmosphere near the South Pole of the gas giant. The images, taken by the space agency's infrared telescope in Hawaii, come on the 15th anniversary of another comet strike. In 1994, Jupiter was bombarded by pieces of the comet Shoemaker-Levy 9. Scientists at NASA's Jet Propulsion Laboratory in Pasadena captured the new images after receiving a tip from an amateur astronomer the night before.