Meteor likely cause of Jupiter flash; Saturn’s B-ring gets scrambled

Jupiter on September 11 through a 12-inch telescope. The Great Red Spot is visible plus a smaller red spot nearby. The little bump at bottom left is the moon Ganymede. Credit: James Willinghan

Still no sign of an impact in Jupiter’s cloud belts by amateur and professional astronomers. I’ve looked at lots of pictures of the planet since Monday and while there are plenty of odd-looking swirls and patches in the clouds, but nothing like the spots that appeared in 2004 and 2009. Odd is the norm when it comes to the solar system’s biggest planet. Jupiter’s ever changing cloudscapes defy the imagination in their weird variety, making it the most rewarding to follow in a telescope. The weather and cloud patterns change constantly much like they do on Earth.

The flash location has been corrected to longitude 345 degrees (System I) and +2 degrees north, putting it squarely within the white Equatorial Zone we talked about yesterday. Based on its brightness and lack of a dark scar, Dr. Michael Wong, assistant researcher University of California astronomy department, concluded that the object that struck Jupiter was too small to singe the cloudtops.

Dramatic dark clouds from the impact of fragments of Comet Shoemaker-Levy 9 were visible even in small telescopes in July 1994. Credit: NASA/ESA

The impacting meteoroid is estimated to have been under 33 feet (10 meters) across. Had an object this size hit Earth’s atmosphere, it would have flared at least as bright as the sun and perhaps sprinkled meteorites along its path.

Unfortunately it appears the space rock that hit Jupiter didn’t have the energy to affect the chemistry of its atmosphere enough to leave a visible trace. In this regard, it resembles the previous two impacts in 2010.

Jupiter’s a big planet with a lot of gravitational pull. Meteors must routinely come crashing in and burn up in its atmosphere. We almost certainly miss most of them just as we do on Earth when bright meteors flash across vast, remote locales like the central Pacific and Canadian Arctic.

Still, not much gets by Earth’s army of amateur astronomers who love the sky and spend countless hours watching and recording it. To date, there have been five confirmed instances of meteoroids/comets bashing Jupiter. The first one was predicted to happen after astronomers discovered that a busted comet would rain down on the planet in July 1994. All the remaining events were discovered by amateurs.

The inner edge of the B-ring (left) shows a clumpy texture from ring particles – mostly ice – bunched together by the gravitational tugs of the moon Mimas. The photo was taken on July 10, 2009 from 198,000 miles away. Credit: NASA/JPL/SSI

NASA released a wonderful picture this week of the outer edge of Saturn’s clumpy B-ring taken by the Cassini orbiter. The other rings appear smooth because the chunks of ice they’re composed of are too small be resolved by the camera. That’s where the moon Mimas comes into play. Mimas (ME-muss or MY-muss) orbits Saturn once for every two orbits the icy particles in the B-ring complete. Regular, repeated nudges by the moon’s gravity are thought to give the ring its sharp edge as well as compress the particles into visible clumps.

Pure speculation on my part, but I wonder if Mimas might create tiny temporary moonlets through its interaction with the B-ring. Could a clump get big enough to gather into an evanescent moonlet before Saturn’s gravity gains the upper hand and disassembles it?

Wide view of Mimas and Saturn taken by Cassini. The B-ring is Saturn’s largest and brightest ring. It’s separated by the outer A ring by a dark gap called Cassini’s Division. Mimas is responsible for removing much of the ring material in the gap. Credit: NASA

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