Jupiter Apparently Smacked by Rogue Object, New Images Reveal

Jupiter has apparently been smacked again by a rogue object hurtling through space, new images from amateur astronomers and NASA reveal.

A giant scar-like blemish has appeared in the clouds near Jupiter?s south polar region, which NASA observed in infrared after receiving a tip from an amateur skywatcher in Australia. The likely impact appears to have occurred exactly 15 years after the remnants of Comet Shoemaker-Levy 9 bombarded the planet in 1994 in an event that was widely predicted and scrutinized as it happened.

The latest impact was not predicted, and it was caught by chance.

?We were extremely lucky to be seeing Jupiter at exactly the right time, the right hour, the right side of Jupiter to witness the event,? said Glenn Orton, a scientist at NASA?s Jet Propulsion Laboratory in Pasadena, Calif., in a statement. ?We couldn?t have planned it better.?

Orton and his colleagues used JPL?s Infrared Telescope Facility atop Mauna Kea in Hawaii to collect evidence of the impact. The initial call came from Anthony Wesley of Murrumbateman, Australia, who told NASA he noticed a new dark ?scar? suddenly appear on Jupiter early Friday between 6 a.m. and 12 p.m. EDT (1000 and 1600 GMT).

A hit on Jupiter

In an observation report posted to his Web site, Wesley said he almost missed spotting Jupiter?s new blemish entirely because he was tired after a late-night skywatching session.

?It was a very near thing,? he wrote, adding that by 1 a.m. Local Time, he decided at the last minute to keep observing for another half hour.

?I'd noticed a dark spot rotating into view in Jupiter?s south polar region and was starting to get curious,? Wesley went on. ?When first seen close to the limb (and in poor conditions) it was only a vaguely dark spot, I thought likely to be just a normal dark polar storm. However as it rotated further into view, and the conditions also improved, I suddenly realized that it wasn't just dark, it was black in all channels, meaning it was truly a black spot.?

The spot, Wesley added, was moving too slow to be a moon and his previous observations from two days earlier showed a pristine, spotless Jupiter. A short while later, he decided to begin contacting people to spread the news of his find.

Orton and his team haven?t stopped tracking Jupiter, which is a gas giant and the largest planet in the solar system.

The near-infrared image collected by his team revealed the odd blemish, which appeared to have a bright center, and what looked like debris to the northwest of the likely impact site.

?It could be the impact of a comet, but we don?t know for sure yet,? Orton said. ?It?s been a whirlwind of a day, and this on the anniversary of the Shoemaker-Levy 9 and Apollo anniversaries is amazing.?  

Other skywatchers have also been tracking the apparent Jovian impact. Lars Zielke, a skywatcher based in Tvis, Denmark, spotted the tell-tale scar to much excitement.

"My camera showed the spot clearly and I was lucky to get at great sequence with the dark spot and Io passing by,? he told SPACE.com. ?I was so thrilled that I didn't stop in time, so I missed the first hours of work this morning."

Echoes of Shoemaker-Levy 9

Between July 16 and July 22 in 1994, Comet Shoemaker-Levy 9 was torn apart by Jupiter?s gravity as it swung past the planet. The remaining pieces crashed into the planet while astronomers looked on with telescopes on Earth and in space.?

It was the first collision of two objects within the solar system in ever observed from Earth.

The impacts were cataclysmic. More than 20 fragments - some as large as 1.2 miles (2 km) across - slammed into Jupiter at 134,200 mph (215,973 kph) as the planet rotated, sending plumes of hot gas into the Jovian atmosphere and causing dark scars that lasted for weeks.

A similar impact on Earth would cause widespread devastation on a global scale.

• Video - The Jupiter Crash of Shoemaker-Levy 9
• The Top 10 Greatest Explosions Ever
• Image Gallery - Jupiter and its Moons

SPACE.com Senior Writer Andrea Thompson contributed to this report from New York City.