The Impact on Jupiter!

Taken on July 19, 2009, Anthony Wesley's image of Jupiter shows a dark marking strikingly similar to the ones left when Comet Shoemaker-Levy 9 crashed into Jupiter in 1994. South is up.
Anthony Wesley
The image at right, taken by Anthony Wesley, a well-known Australian astrophotographer and planetary observer, shows a new dark marking on Jupiter strikingly similar to the ones left when Comet Shoemaker-Levy 9 crashed into the giant planet in 1994. The dark mark, which appeared suddenly between July 17th and 19th, was quickly confirmed by many other observers. Amateurs have been spotting it in 4-inch and smaller telescopes, at least when Jupiter is high after midnight and the atmospheric seeing steadies up. Wesley has put up a Jupiter impact page with more of his own images.

There is compelling evidence, such as the mark's high infrared brightness in reflected sunlight, that it is black dust resulting from the impact of an asteroid or comet. Jupiter's atmosphere normally contains no dust. Leigh Fletcher twittered from NASA's Infrared Telescope Facility in Hawaii: "This has all the hallmarks of SL-9 in 1994 (15 years to the day!). High altitude particulates, looks nothing like weather phenom." (Keep up with Fletcher's tweets, and read his July 22nd blog post about the impact).

"Here is the spot recorded this morning in marginal seeing," writes S&T's Sean Walker. "It appears to me to be spreading out as predicted." The shot was made with a 14.5-inch reflector and stacked video at 3:46 UT July 21, 2009.
S&T: Sean Walker
The spot is located near Jupiter's System II longitude 210°. For the predicted times when it will cross the planet's central meridian, add 2 hours and 6 minutes to each of our predicted transit times for Jupiter's Great Red Spot.

If it's really black debris dredged up by an impact, it will probably become spread out horizontally by jet streams in the coming days, and will thin out to invisibility in a matter of weeks and months — as did the marks from Comet S-L 9.


July 24:More amateur photos are posted at the pages for July 21, July 24, and July 28.

The Jet Propulsion Lab quickly put out a news release with near-infrared (reflected-light) images (also available here if the first site is overloaded.)

Here's a local article from Australia on Anthony Wesley and his discovery.

Keck Observatory takes infrared images.

Here's a fine two-color mid-infrared (i.e. thermal glow) image from the 8.1-meter Gemini North telescope taken on July 22nd. Note the Shoemaker-Levy 9–like splash ring.

The Hubble Space Telescope team suspended its shakedown and calibration of the recently rebuilt telescope and rushed the new Wide Field Camera 3 into service to image the impact mark. Read all about it, and view more Hubble images.

July 27. More than a week after the impact the mark is still quite visible in small amateur scopes. From Victoria, British Columbia, S&T's Gary Seronik writes:

"I saw the impact clearly with my modified StarBlast reflector [on the night of July 27th]. So yes, it can be seen in a fast 4.5-inch scope. The spot looked like a misplaced, slightly diffuse shadow transit. In the best moments of steady seeing, the impact was quite easy to see." However, he notes, its high latitude on Jupiter means that it spends only a short time in from the planet's limb, "so you really have a window of opportunity that is perhaps as short as 15 minutes. After that, it gets tough — at least for a 4.5-inch scope."

July 29. The situation keeps developing; the mark is elongating into a big, diagonal gash. See Fabio Carvalho's images from this morning.

26 thoughts on “The Impact on Jupiter!

  1. Ed

    Minor nitpick: In the second to last paragraph, it says, “If it’s really the black debris from an impact star” I think you mean impact scar.

  2. Dan

    Sweet, the solar system gave my wife and I a present on our 10th wedding anniversary. I dub it the ‘drmuey impact crater of love’ for you, super wife!

  3. David Scherk

    Good thing we saw this coming…oops! An amateur noticed it happenstance. I guess that’s what happens when we don’t look skyward enough. All those disaster movies and still humanity thinks it’s invincible.

  4. Ken Schneider

    This is a perfect example of the terrific work being done by so many amateurs that has an actual effect on professional astronomy (and more). Congrats, and thanks, to Mr. Wesley for his fine work!

  5. Adrian Fitch

    After seeing the S-L impact remains on the upper cloud deck of Jupiter, and the latest discovery, I remembered seeing this type of anomaly before on Jupiter. In 1971 I was a member of the OCAAA in Orange County, California. I observed two dark spots (impact scars), they had a gray ring around each of them. I thought these were just a couple of new storms much like the Giant Red Spot. I did several drawings over the next few nights to document what I had observed. At our next informal meeting of club members, we had scopes set up in the back yard, and I aimed a 8″ newtonian at Jupiter, and showed the guys these two spots, and they kind of laughed and said these were the shadows of two of Jupiter’s moons. I couldn’t convince them that these wer just too big to be shadows! Even thought these were >10 deg in diameter!! on the surface of Jupiter. I have never been able to find any pictures of jupiter during this time period. But I did see the remains of impacts and watched them slowly be absorbed by the wind in the upper atmosphere of the equatorial belt, even though I did not at the time know what I was observing. When S-L impacted Jupiter, everyone was wondering what they would see, and a soon As I saw the results, I knew I had seen that kind of sight before. Another great night for Amateur Astronomy!!

  6. michael Watson

    It is interesting that when D. Simmons of Brisbane, Australia made a 75 minute tim-lapse ‘movie’ of the motion of the new dark spot an Jupiter, it showed that the weather systems were moving substantially faster. If this is an impact hole in Jupiter’s atmosphere why should it be lagging behind the general movement of the atmosphere?

  7. Stephen M. St. John

    Isn’t it odd that a comet or meteor large enough to cause such an impact on Jupiter would go unnoticed by the sky watcher community?

  8. Jerry McMurry

    I went to Christoper Go’s website and viewed his beautiful collection of images of Jupiter, but I cannot see any evidence of the impact on June 27 as Claudio Martinez claims. Claudio, can you clarify what you meant? I do appreciate your calling attention to Christopher Go’s site though; it’s great!

  9. Rod

    The Hubble shot is great! Just think, if our solar system was like many of the exoplanets, we would have a hot Jupiter orbiting < 0.1 AU from the Sun. Perhaps we would never see this impact but our configuration allows for the celestial show. Sky shows like this bring to my mind Matthew 24:29-30.

  10. JAD

    I have a small telescope and weather conditions at my house are not very good. So I was amazed to actually see something on the surface of Jupiter. So I immediately checked the S&T web page and was amazed to read that an impact mark could be seen. But as I read more, I noticed it had to be something else. The impact mark is a black spot on the surface, near one of the poles, which I can’t see from home with my telescope. What I see looks like something bright coming out of the equator horizon. At first I thought it was one of the moons appearing over the horizon, but I can see the four moons elsewhere. Does anyone else see it too? Is it a star on the background? Can you see more than four of Jupiter’s moons?

  11. Eric Peterson

    Remember, we’re still finding small moons of the outer gas giants all the time, and they’re far larger than what hit Jupiter. I’ve seen estimates of the impactor’s size ranging from 1 km down to a few hundred meters. Using 1 km for the diameter because it makes the math easy, a quick calculation shows the angle subtended at Jupiter’s distance is roughly 1.6 x (10 to the minus 9th) radians, a very small angle indeed. Seeing an object of that size and distance, especially if it has a low albedo, is probably beyond or at the extreme fringes of our current technology even if we knew exactly where to look. Shoemaker-Levy 9 had the advantages that it was a) a comet, b) already fragmented and c) emitting a coma, making it comparatively much, much larger and brighter.

    There are billions of such bodies populating the Kuiper belt and the Oort cloud, far too many to ever dectect or track; it’d be kind of like sitting in the middle of a basketball court and knowing where all the bacteria were and what they were doing. Once in a while one falls sunward — once in a great while, something in the Solar System is in the way. All we can do is study what we see and hope to learn.

  12. Toby Cipriano Alarcon Ramirez

    Es uma muy buena revista informativa quisiera leerla en español, y mas compañeros Latinos para poder entrelazar conversacion

  13. Gerald Nordley

    The Hubble press release quotes astronomer Amy Simon-Miller estimating the size of the object as “several football fields,” which I may take to be something of, at most, half a kilometer radius. If it had the same albedo as Jupiter, it would be about 26 magnitudes fainter, or about 24th magnitude. Pluto’s smaller satellites are brighter, so I’m not optimistic about any pre-impact images. But the absence of pre-impact images may hint that the object was an asteroid as opposed to a comet, because the coma and tail (if any) of a comet with a nucleus that size would have been considerably brighter and perhaps might have gotten some attention, as Shoemaker-Levy did.

  14. Moein

    On July 25,I have a Observing program on photometry work and for fun I turn the telescope to Jupiter and see that black blob on the Jupiter near the pole.I was so confuse to see that blob never been there.After that I saw an article on the net and found that this is a Impact.
    I advice to everyone who never seen that blob to never miss that event.
    Clear Sky


    Is there a chance it could have been an object from the asteroid belt? Or even a trojan or greek that became a “Near Jupiter Object” that lost stability (for example because it was far enough from the Lagrangian points? Maybe that’s why we missed it..

  16. Tom Thibault

    Impact still visible as of the early morning of July 28th from Blackstone, Ma. I was up between 3:30 – 4:30 AM viewing and spotted the scar through a C11 SCT. Seeing was great and I concur with Gary Seronik that it appears as a fuzzy shadow transit.

  17. Todd

    yup, that’s right. Observers must now be omniscient and be able to see all and now all when it is going to happen. There’s a lot of universe(s) out there. Pretty arrogant of you to criticize people for not being able to keep track of every little speck of it. And just WTH did you think they were gonna do if it was heading our way besides tell you to kiss your *ahem* goodbye.


  18. Taras

    I’ve been able to see this impact scar several times between waves of bad weather. It’s just like Shoemaker-Levy9 all over again in that the scar is very easy to see as a dark bruise even through my 6-inch Dob. On top of that, I have also seen several white ovals on the planet and the Great Red Spot pinkish color.

  19. KC

    >Isn’t it odd that a comet or meteor large enough to cause >such an impact on Jupiter would go unnoticed by the sky >watcher community?

    Not odd at all – Jupiter is after all nearly 375 million miles away from us. Even with all the professional and amateur astronomers combined, only a small part of the sky is being watched at any one time.