Jupiter's Inferno

The initial, sketchy reports began filtering in by E-mail late Saturday afternoon. First a Spanish observatory announced that it had spotted a plume of gas billowing up from the edge of Jupiter. Then a group of observers in Chile confirmed the sighting, and so did another team based at the South Pole. But although the first of the 21 fragments of Comet Shoemaker-Levy 9 hit the giant planet shortly after 4 p.m. Eastern time, astronomers at the Space Telescope Science Institute in Baltimore, Maryland, had to wait for images to be beamed down from the orbiting Hubble telescope. Finally, at about...