Star Points: The great comet crash bash

Twenty years ago this summer, something unprecedented occurred, way out there. Nothing even close to its magnitude had ever been seen by human eyes before, or since. Although the events then about to unfold had been predicted more than a year earlier, no one knew exactly what to expect.

An extraordinary comet had been discovered the previous year by a team of three comet hunters. Most comets have a single nucleus and maybe a couple of tails. Comet Shoemaker-Levy 9 (or SL-9) had not one nucleus, but more than 20!


Perhaps even more fantastic was the discovery that the comet was orbiting the planet Jupiter instead of the sun. Several decades earlier, Jupiter had managed to "steal" the comet from the sun around which the comet was previously orbiting.

Apparently, during close encounters with Jupiter, the tug of the planet's gravitational sphere of influence had disrupted the comet, causing multiple fragments to separate and spread out along the comet's orbit. The facts of its Jovian orbit and multiple nuclei alone were fantastic discoveries, but the news would get even more surreal in the coming months.


Astronomers studying the comet's orbit discovered that it was ultimately destined to be annihilated in head-on collisions with Jupiter in the summer of the following year. The individual fragments would, over a period of nearly a week, slam into Jupiter like bullets shot from a fully automatic firearm. The energy released from the largest fragment was estimated to be equivalent to six million megatons of TNT. That's around 67 million times more energy than the atomic bomb dropped on Hiroshima during World War II. Plus 20 other fragments slammed into Jupiter as well. It was destined to be an awesome spectacle no matter how you looked at it, and nothing to be missed by even the most casual armchair astronomer.

Excitement grew among professional and amateur astronomers alike. Would the impacts be visible from the Earth? Could they be observed and monitored with amateur equipment? The debate went on as it seemed everyone was reading the predictions and making plans to have a front row seat in their back yard with their favorite telescope to see history being made in what would be the greatest cosmic collision in recorded human history.

I was looking forward to experiencing it as well, but soon there was a big, fat fly in the ointment. Unbeknownst to me, my family had made plans to spend time in Ocean City, meeting another family who was renting a condo for the week. I love the beach as much as the next person, but I also didn't want to miss one of the greatest natural spectacles of the 20th century anywhere in the solar system.

Family politics dictated that staying home and missing the family vacation would not be the prudent thing to do. Then I recalled a gentleman I had heard about in O.C. He was the owner of a domed observatory with a rather large refracting telescope with an 8-inch diameter lens. A friend of mine had met him a few years previously and had been told that any astronomer he knew was welcome to drop in for a visit.

I telephoned the O.C. astronomer, who had heard about the upcoming comet crash. He said to give him a call when I got to O.C. It was a relief to have a backup plan in hand. Now I could finally enjoy planning the trip with the rest of the family.

Upon arriving in O.C. I called the man with the observatory and got some distressing news. It seems he had converted his domed observatory into an apartment, and a renter was actually living inside the dome. But the news wasn't all bad. He had mentioned the telescope, comet and Jupiter to the renter who had expressed an interest in viewing it himself. So the tentative plan was that he and his tenant would remount the telescope on the day of the evening that the first chunks would crash. He said to call again that day and we'd arrange getting together to observe.

After a day at the beach and a nice dinner I telephoned my new astronomer friend to compare notes and discuss when to open up the dome. Unfortunately, his response was far from enthusiastic. His latest plan was to watch the live coverage on TV instead. Besides, he reasoned, nothing would probably be visible in the telescope anyway, so why bother with it.

I countered that not only was it almost guaranteed that the comet impacts would be clearly visible in Earth-based telescopes due to the predicted energies involved, but that his premium telescope would certainly reveal detail through the eyepiece to the human eye that would be invisible at TV resolution.


The conversation then switched suddenly and unexpectedly to guitars, his newest interest, which had usurped his curiosity of the night sky. After explaining that he planned to spend the night playing one in front of his TV, he asked if I might be interested in purchasing a specific used telescope, for a certain price. When I replied that I didn't have $40,000 on me to spare, he asked me to stop telephoning, and that was that.

The new prospect of missing out on seeing the first night's impacts live and through a telescope was somewhat depressing. The other adults had their own plan to go out for the night, and I joined them. When we returned I switched on the TV to check the news.

The first impacts were dramatic and widely observed. From the coverage it was clear that although I had missed the first night, I would get to see some of the remaining impacts with my own telescopes once I returned home.

Indeed, the impact regions were clearly visible in even the smallest telescopes. The Earth-sized scars at the collision sites in Jupiter's atmosphere remained visible. I made sketches and identified the various impact sites for weeks to come.

Over a decade had passed and once again we were in Ocean City. A woman collecting the $9 per person admission at a club asked if any of us had ever been there before. After thinking for a moment I explained that I had once been there years before on the first night of the bombardment of Jupiter by the disrupted fragments from Comet Shoemaker-Levy 9. With eyes now wide, she opened the velvet rope and took a hasty step back. "No charge," she said, allowing us to pass through.

Perhaps she thought it better not to argue with the crazy talking man.


Curtis Roelle is a member of the Astronomical Society. His column appears the first Sunday of each month. His website is, and he can be reached at