They’re still waiting.
“It’s as if Jupiter just swallowed the thing whole,” says Anthony Wesley of Australia, one of two amateur astronomers who recorded the initial flash. The other, Christopher Go of the Philippines, says “it was thrilling to see the impact, but the absence of any visible debris has got us scratching our heads.”
A color composite image of the June 3rd Jupiter impact flash. Credit: Anthony Wesley of Broken Hill, Australia. [more]
Indeed, it is a bit of a puzzle. “We’ve seen things hit Jupiter before,” says planetary scientist Glenn Orton of JPL, “and the flash of impact has always been followed by some kind of debris.”
For instance, when fragments of Comet Shoemaker-Levy 9 hit Jupiter in 1994, each major flash observed by NASA’s Galileo spacecraft produced a “bruise,” a murky mixture of incinerated comet dust and chemically altered Jovian gas twisting and swirling among the native clouds. Just last year, in July 2009, Wesley discovered a similar mark thought to be debris from a rogue asteroid crashing into the planet.
So where is the debris this time?
A possibility offered by some observers is that the flash wasn’t an impact at all. Maybe Go and Wesley witnessed a giant Jovian lightning bolt.
{mosimage} Click on the image to view a movie of the impact recorded by Christopher Go of Cebu City, the Philippines.
“I consider that very, very unlikely,” says Orton. “NASA spacecraft have seen lightning on Jupiter many times before, but only on the planet’s nightside. This dayside event would have to be unimaginably more powerful than any previous bolt we’ve seen. Even Jupiter doesn’t produce lightning that big.”
Nor could it be a flash of lightning in Earth’s atmosphere fortuitously happening in front of Jupiter. Simultaneous observations of the same flash from widely-spaced observatories in Australia and the Philippines rule that out. For the same reason, it couldn’t be, say, a terrestrial meteor or any other phenomenon in the atmosphere of Earth.
In short, the flash really happened at Jupiter.
Curiously, the impactor (if indeed this was an impact event) struck right in the middle of Jupiter’s South Equatorial Belt (SEB), one of the two broad stripes that girdle the planet. This is “curious” because the SEB itself vanished earlier this year. Orton has proposed that the missing belt still exists, it’s just temporarily hidden underneath some high-altitude cirrus clouds.
Could those very same clouds be hiding the impact debris?
He doesn’t think so. “The flash came from an altitude above any cirrus layer, so the debris should be plainly visible—if there is any.”
{mosimage}Clouds of debris mark Jupiter’s cloudtops following the SL-9 impacts of 1994. [(Visited 25 times, 1 visits today)
