Wednesday, September 12, 2012
JUPITER SWALLOWS AN ASTEROID: The fireball was probably caused by a small asteroid or comet hitting Jupiter. Apparently, the giant planet swallowed the impactor whole.
Astronomers are abuzz over sightings of a flash on Jupiter — which suggests that the giant planet has taken another bullet for the solar system team.
Monday's report follows Jovian impacts in 2009 and 2010. As in those earlier cases, the call has gone out to look for any visible scars on Jupiter's cloud tops. That would be a sure sign that an asteroid or comet was drawn in by the planet's gravitational pull, potentially saving us from a cosmic collision threat.
"It's kind of a scary proposition to see how often Jupiter gets hit," said George Hall, an amateur astronomer from Dallas who captured the flash on video this morning.
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Hall didn't actually see the hit when it happened. Early Monday morning, he brought out his 12-inch Meade Schmidt-Cassegrain telescope with the Point Grey Flea3 video camera attached, just to capture imagery for a composite picture of Jupiter. "Jupiter happens to be ideally positioned at about 6 o'clock in the morning," he explained. "It's right overhead."
That also just happened to be the time when another amateur astronomer from Oregon, Dan Petersen, made a visual observation of the flash. Peterson didn't capture an image of the flare, which lasted only a couple of seconds, but he did send his sighting report to other astronomers.
"I decided to just observe on this particular morning," he said in an email to Philippine amateur astronomer Christopher Go. "Had I been imaging I probably would have missed it while playing with webcam settings and focusing."
Go relayed Peterson's report to the Association of Lunar and Planetary Observers' Jupiter forum, which set the place buzzing. Hall noticed the online hubbub and went back to review the video file on his computer. "I never would have looked" if it weren't for Petersen's report, Hall told me. The time stamp on Hall's video matched up with Petersen's observations — 6:35 a.m. CT, which is 7:35 a.m. ET or 11:35 GMT.
Hall reported his find, and shared in the accolades from fellow amateurs.
Universe Today's Nancy Atkinson quotes amateur astronomers as saying that the impact area should come back into view starting at about 1 a.m. ET Tuesday.
Jupiter impacts are of great interest to astronomers, amateur and professional, because they're part of the orbital billiards game that has shaped our solar system. In some cases, the cosmic interloper is destroyed before it has any visible effect on Jupiter's cloud tops. In weightier cases, the object breaks up and leaves black marks on the planet's atmosphere. The case of Comet Shoemaker-Levy 9 in 1994 is the most notable in recent memory.
Beyond the planetary science, there's the "phew" factor: Astronomers suspect that giant Jupiter's gravitational pull serves as a cosmic shield, sweeping up incoming objects that would have a deadlier effect if they were to slam into our planet. Some scientists say that without Jupiter, life on Earth wouldn't have had much of a chance.
How big was the object that caused Monday's flash? Stay tuned: We may get a better fix on that once astronomers get a follow-up look. But Hall probably won't be among the legions keeping watch on Tuesday morning. He's lost enough sleep over the past couple of nights.
"I'm almost 70 years old," he told me, "and it takes a lot out of me to get up at 4:30 or 5."
Update for 1:25 p.m. ET Sept. 11: So far, observers have seen no conclusive sign of a scar left behind on Jupiter by the flash, going by the chatter on the ALPO Jupiter forum and the Cloudy Nights website.
Update for 3:15 p.m. ET Sept. 11: Hall has posted a must-see video of the flash on Flickr. But don't bother popping the popcorn: The video clip is just four seconds long.