The Buildup
I first met David Levy before he had discovered any comets (his latestcount is too high for anyone to remember). I remember being seated arounda breakfast table with him at a Riverside Telescope Makers Conference.He appeared to be quite shy and said little. There was nothing about himwhich foretold his incredible destiny. Eugene Shoemaker was a hero of sortsfor me when I was young, during the Apollo era. I wanted to move to Flagstaffand follow in his footsteps, working at Meteor Crater and Lowell Observatory.Shoemaker always seemed destined for big things. The discovery by Shoemaker,his wife, and Levy of a broken comet in orbit around Jupiter was strangeenough, but when it became apparent that the 21 fragments would impactthe planet I couldn't believe it for a while. At first I had visions ofhuge impacts visible to the naked eye. I thought of the black spot in themovie 2010 which "ate" Jupiter, igniting the planet into a secondsun. I wondered if the long standing features on Jupiter such as the redspot might have formed from impacts. I thought of the coincidence withthe 25th anniversary of Apollo 11, and wondered more than once whethersomeone was sending us a birthday present. But then reality struck, asthe visibility the predictions became more gloomy. It appeared we wouldprobably see nothing after all. Due to a heavy work schedule I shelvedplans to rebuild and re-aluminize my 12.5" f/6 - why bother?
Mt. Wilson Excursion
Southern California was to have three opportunities to observe fragmentimpacts. The first of these was to occur on Saturday the 16th just priorto sunset. I had originally planned to observe at Highridge park, but whenI found a way to join a group observing with the 100" telescope onMt. Wilson, I felt I could not pass up the opportunity. I felt it mighttake that much aperture to see anything, and good CCD imagery in near infraredmight show things undetectable in the visible. In addition, the Hookertelescope was another of my childhood heroes, and I had never had a chanceto see the instrument. The 100" was just coming out of a mothballsleep of several years, and the impacts were to be its first good workoutafter refurbishing. Mt. Wilson has some of the best observing conditionson the planet. I just had to be there. My wife Nina and I arrived earlyto browse the grounds and sit in on the pre-impact talks. Several otherclub members (Jim Tobin, Paul Harris and family, Mike Mayerchak, and AlanGayda) had arrived even earlier to take the guided tour of the observatories(they raved about the tour, it is offered every week). In the course ofthe evening we ran across at least a half dozen other members. In the earlyafternoon we heard the first reports of the A impact from some of the professionalson the mountain. Word was that South Africa saw a plume. Things were gettingexciting! The talks were excellent. First, Don Yeomans of JPL gave a fullreport on the history of the comet and the predictions for the impacts.He showed some outstanding simulations (good enough they should sell framesof it on T-shirts). Next Robert Jastrow, another childhood hero, (remember"Red Giants and White Dwarfs"?) spoke on how the impacts mightchurn up organic molecules, or even organisms. His talk was awe inspiringbecause it made one realize the magnificence of the events. As sunset approachedwe gathered around a monitor to watch images from the 100". Here wemet our first disappointment. The CCD selected was simply a color videochip, with contrast too low for this kind of work. In addition, workingin the visible, with no filtration, they could not expose the array tolight until nearly a half hour after impact! Intermittent high clouds andturbulence interfered as well. Then a rumor circulated that someone hadinadvertently opened the dome during the afternoon and thrown the primarymirror out of thermal balance. There is a standing joke among several ofthe club members that CCD images are all playbacks or fakes, since noneof us has ever seen even one good image captured while we were watching.We looked at each other and shrugged our shoulders one more time. Betswere started regarding whether we would see anything at all. We startedwondering whether we would be better off in the parking lot where someamateur scopes were set up. Finally an image was achieved, but there wasnothing to be seen out of the ordinary Strike one. Later we would learnthat fragment B turned out to be a dud, and the remains of A had rotatedbehind the planet. We took some photos of city lights and looked througha Meade 16" in the parking lot before leaving about 10 PM (to be homefor the midnight impact of C - there might be something on TV!). All ofus observers had completely given up on seeing anything from the impacts,figuring it would take a monster telescope working in IR to play in thisgame.
Discovery
On Sunday Internet downloads showed that this was a big show! But onlyin infrared. Oh Well. The most impressive shots were from the Keck telescope.These were personally inspiring, since Nina and I had been privileged tosee the telescope under construction on Mauna Kea in 1989. We wonderedthen what new discoveries it would make (and this was not something thatoccurred to us!). At a Chinese dinner that afternoon Nina got a fortunewhich read "There is a prospect of a thrilling time ahead for you".We hoped it meant something about the comet, but soon forgot about thefortune. In the evening I decided, just on a whim, to try out my Celestron3.1 " refractor with a 4.8mm Nagler purchased some time back (andwoefully under-used). I wondered just how good the images with the neweyepiece might be, and how the little telescope would stack up againstthe 100" imagery. The sun had just set, and the sky was still brightwhen I found Jupiter and brought the scope to bear. My first words were,"My god, that's an impact sight!!!". What I saw was the mostdistinctive feature on the face of the planet. It looked like nothing elseI had ever seen (except for a satellite shadow, which I quickly eliminatedfrom consideration). I wondered if it might be a natural feature I didn'tremember. My planetary observing was a bit rusty. However, I could notremember this kind of feature at this high latitude in my nearly 30 yearsof observing Jupiter. In addition, this black spot had a halo around it!As I watched for a few minutes I found there were two black spots separatedby about 30 degrees in longitude, and they both had haloes. I got on thephone and started an impromptu calling tree of most of our dedicated observers.Soon we were exchanging excited phone calls and comparing details. Twothings became apparent quickly. First, there was a third black spot whichhad risen over the eastern limb of the planet. Second, it looked like myhouse, on the lee side of the peninsula, had the best weather. We madeplans to meet at my house on the evening of the 20th to celebrate Apollo11 and watch impact R. I went back to the scope and made some sketches(my little 3.1 is on an alt-azimuth mount, the C-8 in the garage actuallygives poorer images, and the 12.5" was still in mothballs, so I hadno photographically capable instruments). That first spot had to be fromthe most recent impact that afternoon but, while it was at about the rightlatitude, it appeared off in longitude. Then I remembered something onInternet about how the impact features were lagging behind the normal planetaryrotation rate. Hmmm. As I went to bed I still wondered if these were notjust regular features and I had just been carried away with the excitement.After all, we had no reason to think there would be any features discerniblein small telescopes. We had seen no visible light images showing such featuresfrom any observatory. I did not sleep well.
The Morning After
On Monday morning I turned on the TV. After a few channels of the usualTV wasteland I stumbled across a near UV (that's nearly visible) imagefrom Hubble, and there they were - the three black spots! I spent muchof the day at work pointing out that I am the only guy I've ever heardof who made a discovery with a 3" refractor which had to be confirmedwith the Hubble Space Telescope! That night I observed more impact sites.The impact site of fragment H was spectacular as it came around the easternlimb. With the dust clouds on the limb I was looking through the maximumpath length and the scar appeared to take a bite out of the planet. Itreminded me of the appearance of a solar eclipse a few minutes after firstcontact, but the edge of the bite was straight. A better description isthat it looked like Jupiter had been dropped and dented. As the impactscar rotated into view it looked smaller but it still looked nearly twicethe size of Ganymede! That's about the size of the Earth. On Tuesday Iattended an Apollo 11 observance where I work. My company (TRW) built theLunar Module Descent Engine, the Lunar Module Abort Guidance System, anddeveloped many of the Apollo mission requirements. That was back when Iwas a kid, and those events inspired me to pursue the career path I chose(ultimately developing mission requirements for future space systems).It was great to have the opportunity to hear from the guys who made ithappen. One fellow told me he had been sent to the Cape in the last threeweeks before the launch to determine just when the descent engine tankswould run dry. He said he had his own timer running during the landing,and he figured Armstrong had already run out of fuel a couple of hundredfeet off the surface!
A Big Splash for the Anniversary
On Wednesday night a large crowd gathered in my front lawn in San Pedrowith an 18" newtonian, C-8, 5" refractor, 4" refractor,and my trusty little 3.1". My neighbors were a bit overwhelmed, butthey all got a chance to see the impact spots, and seemed pretty happywith their choice of neighbor. Seeing varied from mediocre to excellent,and at the best we thought we could see eleven individual impact scars.We set up a TV near the snack table for Apollo 11 programs, and the PBSspecial on the impacts. The shy David Levy was now wearing a tuxedo onnational TV! I'm sure his friends will not let him live it down at nextyear's RTMC, since each year there is a prize awarded for "overdressingat the conference". As the time for impact R approached we mannedeach eyepiece with our most experienced observers, hoping to see evidenceof the fireball peeking around the limb. At R minus four minutes a clouddeck moved in, and that was that. I muttered something to Nina about notblowing thousands of dollars on a solar eclipse expedition in November,since I felt I could predict similar results). We consoled ourselves withTV and looking at meteorite samples. Three of us present were meteoritecollectors, and we had a couple of samples of what may be comet nucleusmaterial (types Cl and CM2). It was pretty heady stuff to hold a pieceof a comet in your hands and look at what was going on at Jupiter. Laterwe found out that impact R was spectacular, and apparently Hawaiian observersdid see the fireball. Strike two.
Last Chance
The last opportunity to see an impact was with fragment V on the followingnight. Most of the same crowd gathered again, and some new neighbors introducedthemselves. We manned the eyepieces once again with our most seasoned observers.We watched from before the earliest predictions to well after the lastones, and saw .... nothing. Maybe you did need infrared to see fireballs.We later learned that V was another dud. Strike three. But Wait
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As I write this note it is Thursday night the 29th (30 July in UTC).It is a full week after the last impact now, and most people have not givenJupiter a second look. Ha! The biggest surprise was yet to be. I am lookingtonight at two enormous impact scars, each from multiple impacts. Eachone is several times bigger than the Earth. That's right, they're GROWING.I can see at least eight of the original impact spots, and they don't seemto be dissipating much. I'm starting to think about 2010 again. When inthe movie Dave is asked what is going to happen, his response is "somethingwonderful". I am here to tell you, this is something wonderful. Theentire south polar region is becoming hazy with what may be high altitudecomet dust. Most amazing of all, my suspicion about the impacts creatingnew long-lived features may prove to be correct. The two largest scarsare growing in longitude and threaten to grow together, perhaps startinga new planetary belt. All of the impacts are at roughly the same latitude,and thus may all participate in belt formation. If this turns out to beone way in which belts form, and if the only way all impacts can occurin the same latitude is for the comet to be broken up and orbiting Jupiter...... well there are a lot of belts on Jupiter. I wonder if these eventsare so rare after all. Maybe someone is trying to tell us something.
Aftermath
These have been two of the most exciting weeks of my life. I have beenon an emotional roller coaster with each new image and view. In this noteI have barely scratched the surface. I never mentioned my (unsuccessful)attempts at monitoring decameter radiation from the impacts, or the manyother fantastic effects observed from the major observatories. I have hadsome feelings of sadness mixed with the excitement. Jupiter may never bethe same familiar friend. But in my old age I may be able to tell youngstersI remember Jupiter before the impacts. On the Sunday after the impactsI watched archival TV footage of the original live coverage of Apollo 11,and saw a slightly more youthful Shoemaker walking around Meteor Craterspeaking of impacts, and a visionary, romantic Jastrow speaking of howthe astronauts might find organic matter, or even life on the lunar surface.Tonight I heard about the possible detection of "strange" organicmolecules in the Jovian impact plumes. Everyone has dreams. Some come true.
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