SMALL TELESCOPE, BIG SPOT: Amateur astronomer Anthony Wesley tipped off professional observers at large institutional telescopes that Jupiter bore a fresh scar, likely from a major impact. In this photograph taken by Wesley, the mark is visible as a dark patch near the top of the image.
Image: Anthony Wesley
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A backyard astronomer in Australia made a major discovery early Monday morning when he noticed a newly formed spot on Jupiter—a spot that academics and NASA astronomers have now confirmed marks a recent impact on the giant planet.
Anthony Wesley of Murrumbateman had a new 14.5-inch Newtonian telescope at his home observatory trained on Jupiter when he noticed something unusual: a dark spot on the planet's outer layers that had not been there two days before. Because its location, size and rotation speed did not jibe with any of Jupiter's moons or their shadows, nor with any of its known atmospheric features, a feasible explanation eluded him. Observed massive impacts from comets or asteroids are extremely rare—when Comet Shoemaker-Levy 9 slammed into Jupiter in 1994, it was an unprecedented event watched intently from countless observatories.
"Could it actually be an impact mark on Jupiter?" Wesley wrote in his observation report. "I had no real idea, and the odds on that happening were so small as to be laughable, but I was really struggling to see any other possibility given the location of the mark."
He continued to photograph the planet, then returned to his house to e-mail others about what he finally concluded had to be a scar from a recent impact. Leigh Fletcher, a postdoctoral astronomer at NASA's Jet Propulsion Laboratory in Pasadena, Calif., happened to be part of a team with observing time on the NASA Infrared Telescope atop Mauna Kea in Hawaii when he and his colleagues got word of Wesley's unusual sighting. What is more, Fletcher's group was already going to train the three-meter telescope on Jupiter to observe its storms, working remotely from Pasadena.
"You can imagine the scene: We're all extremely excited, crammed around the computer screen to see those first images from the telescope facility," Fletcher says. "And there it was: an extremely bright feature on the southern hemisphere of Jupiter." It looked just like a medium-size impact from Shoemaker-Levy 9, Fletcher says, confirming Wesley's assessment.
Paul Kalas, an astronomer at the University of California, Berkeley, also had observing time booked on Mauna Kea, at the 10-meter Keck 2 telescope, when he and his colleagues read about Wesley's discovery on the blog of Kalas's Berkeley colleague Franck Marchis. Kalas and his team were using Keck to look for the exoplanet Fomalhaut b, some 25 light-years away. (Fomalhaut b was one of the first extrasolar planets whose orbit was confirmed with photographic evidence in November.)
Kalas and his colleagues took about 90 minutes away from their Fomalhaut observations to check on Wesley's purported find. What they saw was an unmistakable spot glowing brightly in the infrared where something had punched through Jupiter's outer layers. "We agreed with the amateur astronomer that this was an impact event," Kalas says.
"You have layers in Jupiter's atmosphere—you have a cloud deck, and above that is an atmosphere which absorbs infrared radiation, so in the infrared Jupiter kind of looks dark," Kalas explains. "So if you have something punching through the atmosphere, hitting those clouds, and pulling up material in a giant plume...then all of a sudden Jupiter looks bright at that spot in the infrared." Fletcher says the scar should heal over the coming days and weeks, providing astronomers a look at Jovian atmospheric meteorology working in real time.
His team and others have much work to do to analyze the data collected from the various telescopes to reverse-engineer just what kind of impact it was. "The event is so recent, I don't think people have sharpened their pencils yet to get going," Kalas says.
Whatever the culprit, the arrival of such a rare event, exactly 15 years after Shoemaker-Levy 9 was in the midst of bombarding Jupiter, is an unexpected boon to planetary scientists. "These are the only two occurrences of an impact being viewed on Jupiter," Fletcher says. "To be able to view another one in our lifetime is extremely exciting."
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10 Comments
Add CommentThis is very, very cool... But I'm a little concerned that something capable of leaving an "Earth-sized impact crater" could be rattling around our solar system without us noticing until after the fact... Not that we could have done much about it had it collided with our little blue marble, but gosh it'd be nice to know.
Reply | Report Abuse | Link to thisB.B.
Reply | Report Abuse | Link to thisDon't worry it can happen any time. We have lived happily for so long unaware of such impending catastrophes, one is due to hit us sometime soon, nothing we can do about it.
Why on earth would you want to know? Live every day to the full, asteroid or now asteroid, we all die one day.
After an asteroid impact life will return to earth stronger and better than before.
Could not agree with you more, scientific earthling.
Reply | Report Abuse | Link to thisCould not agree with you more, scientific earthling.
Reply | Report Abuse | Link to thisI propose that the event be referred to as "the Wesley Impact" or some similar appelation which incorporates the name of the armature astronomer who first brought it to our attention.
Reply | Report Abuse | Link to this"armature astronomer" Well, there you go, spinning--again.
Reply | Report Abuse | Link to thisActually, that's Jupiter's "purpose"; to pull in the big stuff floating around the solar system and keep it impacting the smaller inner planets.
Reply | Report Abuse | Link to thisI quoted the word purpose on purpose. My post in no way defines a design to the solar system put in place by anyone or anything. The reason life has been able to flourish on our planet is due to the fact that we've got a big, gaseous bodyguard to keep the bullies away.
Realise that Jupiter's gravity is rather intensely greater than that of the earth's so an impact has a substantially greater kinetic energy gain from falling down its gravity well. That being said, we live here and a large impact will no doubt wipe out much life on the planet. With our present technology all it would take is money from the larger nations to build a protective shield to prevent such an occurrence however unlikely in the short term. Inevitably, we will be hit once again and then after that and after that. It is the consequence of being in a solar system filled with the detritus of formation. It is now up to us to decide to defend our planet from these random infalling objects, big and small. It is a matter of the politicians deciding that that is more important than their stupid weapons, missiles and fighter jets for which the world fritters away its resources and wealth instead of making the earth a safer and better place to live.
Reply | Report Abuse | Link to this"Why on earth would you want to know? Live every day to the full, asteroid or now asteroid, we all die one day."
Reply | Report Abuse | Link to thisBecause we might be able to prevent it. This is why we want to know.
Such impact on Jupiter might be relatively rare such as one every 15-100 years may be (?) But on Earth it should be a log scale less frequent because of the orbit of our Planet and it's size way smaller and lighter that Jupiter or the Sun.
Asteroids and comets are much more likely to hit one of these two instead of earth.
Earth seem to sustain a massive impact every 60-100 million years or so.
Hopefully by the time the next massive impact is due we will have the technology to deflect it.
No need to say that this second Jupiter impact is another reminder that we have better to watch the sky anyway.
"I propose that the event be referred to as "the Wesley Impact" or some similar appelation which incorporates the name of the armature astronomer who first brought it to our attention."
Reply | Report Abuse | Link to thisAgree.