Message #163682

[Brandi Dye]

Still, this small object packed a punch–it created a debris field of scattered gases on Jupiter the size of the Pacific Ocean. And that gas cloud is a clue that suggests the direction of the impactor. On JPL's official blog, Fletcher says that because the infrared images show that the massive field scattered toward its upper left (as seen from Earth), the impactor probably came from that direction and struck the planet sometime in the 24 hours before Wesley first spotted the scar. Once astronomers refine this information, it might even be possible to go back to old pictures of the sky, look at where the impactor should be coming from and find it, says planetary scientist Mark Gurwell of the Harvard-Smithsonian Center for Astrophysics.

So far, researchers have narrowed down the direction and size of the impactor, but one big question remains: Just what kind of object was it? To answer this question, the researchers again will turn to Shoemaker-Levy 9, says Glenn Orton, a senior research scientist at JPL. The 1994 impacts left traces of hydrogen cyanide, carbon monoxide and other chemicals in Jupiter's atmosphere. Now Orton is using spectroscopic analysis, which determines the composition of Jupiter's atmosphere by the light it gives off, to see if the 2009 impactor left a similar signature, which would indicate it was probably a comet as well. Orton says the best explanation is a comet or other icy body–nearly all the objects roaming that area of the solar system are icy–and finding oxygen traces would just about cinch the case. But making these observations through our own oxygen-rich atmosphere is a difficult task, he says, so the answer may take some time.

While questions remain, astronomers are carrying on their sleepless race to record all the information they can from Jupiter's new scar before it's too late. "We have no idea how long it will last," de Pater says. Orton says he's run himself and his grad students ragged as he guided observations in Chile by phone from his California office until 1 am and then started again at 7 am, when Jupiter's scar became visible to the telescopes in Hawaii. "I'm exhausted," he says. Others are joining the party too. Late last week, the Hubble Space Telescope's brand-new camera, which space shuttle astronauts installed in May, snapped the sharpest visible-light photo yet taken of the impact site. It'll take weeks and months to unravel all the data, Gurwell says, but for now astronomers' priority is to gather all the evidence they possibly can. "We'll shoot first and ask questions later," he says.
http://www.popularmechanics.com/science/air_space/4326395.html