Jupiter Impact: Mystery of the Missing Debris

Jun 15, 2010 by Dr. Tony Phillips
A color composite image of the June 3rd Jupiter impact flash. Credit: Anthony Wesley of Broken Hill, Australia.

On June 3rd, 2010, something hit Jupiter. A comet or asteroid descended from the black of space, struck the planet's cloudtops, and disintegrated, producing a flash of light so bright it was visible in backyard telescopes on Earth. Soon, observers around the world were training their optics on the impact site, waiting to monitor the cindery cloud of debris which always seems to accompany a strike of this kind.

They're still waiting.

"It's as if just swallowed the thing whole," says Anthony Wesley of Australia, one of two 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 has got us scratching our heads."

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 hit Jupiter in 1994, each major flash observed by NASA's produced a "bruise," a murky mixture of incinerated 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.

"I consider that very, very unlikely," says Orton. " 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?

Clouds of debris mark Jupiter's cloudtops following the SL-9 impacts of 1994.

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."

The best remaining hypothesis is that the impactor was small, packing just enough punch to make a flash, but without leaving much debris.

One thing is sure: "Jupiter is getting hit more than we expected," says Don Yeomans, head of NASA's Near-Earth Object program of JPL. "Back in the days of Shoemaker-Levy 9 (SL-9), we calculated that we should see an impact on Jupiter once every hundred years or so. We considered ourselves extraordinarily lucky to witness the SL-9 event."

"But look where we are now," he continues. "Anthony Wesley has observed two impacts within the past 12 months alone. It's time to revise our impact models [particularly for small impactors]."

Clearly, researchers have a lot to learn, not only about how often Jupiter gets hit, but also what happens when the strikes occur.

"We're continuing the search for debris at a number of major observatories, including Hubble," says Orton. Future observations sensitive to very small amounts of debris and to gases pulled up from Jupiter's deeper atmosphere may yet reveal what happened to the flashy impactor of June 3rd—or lead researchers in new directions entirely.

Stay tuned!

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Doug_Huffman
1 / 5 (5) Jun 15, 2010
Nor could it be a flash of lightning in Earth's atmosphere fortuitously happening in front of Jupiter. ... For the same reason, it couldn't be ... any other phenomenon in the atmosphere of Earth.
A straw herring argument posed to illustrate such supposed learning from the science subdivision of journalism. Tsk tsk tsk
yyz
5 / 5 (5) Jun 15, 2010
DH,

The fact that the event was seen by two widely separated observers at the same time serves to rule out phenomena occurring in Earth's atmosphere as an explanation (parallax rules this out). While not mentioned in the article, the possibility that this was a glint off a satellite (a real possibility, BTW) is also discounted due to the simultaneity of the event and parallax-flash geometry conditions.

Further observations of the impact area using near infrared and narrowband methane filters may be able to tease out some details of this impact event. Of course, even a non-detection would help astronomers constrain parameters on the body itself.
Shootist
4 / 5 (4) Jun 15, 2010
There would be obvious differences observed in an impact from a carboniferous chondrite, a stony chondrite, a nickle-iron meteor and a "dirty snowball".

Spectral analysis, of the impact, should be able to determine the major constituents of the impacting body.

A nickle-iron meteor would probably forgo the dust.
Farrell
not rated yet Jun 15, 2010
Could it have been something that simply skipped on Jupiter's atmosphere, and continued off into space, or some eccentric orbit around the planet?
yyz
not rated yet Jun 15, 2010
@Farrell,

"Could it have been something that simply skipped on Jupiter's atmosphere, and continued off into space"

Interesting suggestion , but the brevity of the single event (~2 sec) and its relatively high luminosity would argue against this explanation.

"or some eccentric orbit around the planet?"

I guess this might be possible, but an eccentric orbit that dips into the upper Jovian atmosphere is highly unstable and might survive only one pass before succumbing to gravity, meaning we got improbably lucky to see see this one event (think Comet Shoemaker-Levy 9, which was shredded by a close pass to Jupiter before multiple impacts).



Farrell
not rated yet Jun 16, 2010
@YYZ,re: eccentric orbit

I was thinking more of the idea that if it did just skip once then there would be a cone of probably of where it went afterwards, either off into space, or into an eccentric orbit around the planet to look for it. If nothing else explains why there were no debris, even if a skip is unlikely, checking the possible exit or orbits, if it was bigg enough to be seen would be an idea. IMOHO.
tflahive
not rated yet Jun 16, 2010
Could be an ultra-high-energy cosmic ray (UHECR). But the typical flash in the earth's atmosphere is Cherenkov blue. Question, could the difference in color be due to the Jovian atmosphere? Or did the "image filtering" change the color?
yyz
not rated yet Jun 17, 2010
@Farrell,

While it would be of scientific value to determine the trajectory of this object through the Jovian atmosphere, it's not possible to do this based on a single positional observation as in this case.

@tflahive,

The flash observed is too bright to be caused by UHECRs. On Earth, Cherenkov air showers are observed in the night sky and appear quite faint. This was observed on the daylit side of Jupiter. Also, if it was a UHECR event, we should see many more on Jupiter every day, due to the known statistical occurrence of these high energy events.

Jigga
1 / 5 (2) Jun 17, 2010
.Jupiter is getting hit more than we expected..
Solar system is approaching large massive objects, which attracts & changes paths of various asteroids. One of possible explanations is there:

http://news.scien...clo.html
Newbeak
5 / 5 (1) Jun 20, 2010
I find it surprising that the results of almost any impact with Jupiter leaves visible evidence,considering that the planet is a gaseous giant with a 5000 Km deep atmosphere..