Apparently, something hit Jupiter during the early hours of Sept. 10th (11:35 UT), igniting a ferocious fireball in the giant planet's cloud tops. Amateur astronomer Dan Peterson Racine, Wisconsin, saw it first through his Meade 12" LX200 telescope. "It was a bright white flash that lasted only 1.5 - 2 seconds," he reports. Another amateur astronomer, George Hall of Dallas, Texas, was video-recording Jupiter at the time, and he confirmed the fireball with this video screenshot:
Jupiter Impact
© George Hall
Impact site coordinates: longitude 335o (system 1) and latitude +12o, inside the North Equatorial Belt's southern section.
The fireball was probably caused by a small asteroid or comet hitting Jupiter. Similar impacts were observed in June and August 2010. An analysis of those earlier events suggests that Jupiter is frequently struck by 10 meter-class asteroids--one of the hazards of orbiting near the asteroid belt and having such a strong gravitational pull.

Astronomers around the world will now begin monitoring the impact site for signs of debris--either the cindery remains of the impactor or material dredged up from beneath Jupiter's cloud tops. Some impacts do produce such debris, while others don't. Researchers aren't sure why; perhaps this event will provide some clues. Stay tuned for news about what happens next.