Nineteen years ago tonight, on July 23, 1995, a curious coincidence occurred. Two men, unknown to each other but living in the same country and actually not that far from each other, were gazing at the night sky when each of them, independently of the other, discovered something new. One of the men, Alan Hale, was an astronomer, noted atheist and skeptic and advocate of scientific literacy within society. He had a Ph.D. in astronomy and had worked with the Jet Propulsion Laboratory in California on the Voyager 1 project, but he happened to discover the fuzzy object in the sky with an ordinary home telescope in his driveway in Cloud Croft, New Mexico. Quickly checking a chart of sky objects, he determined the fuzzy thing hadn’t been seen before, and that he had discovered a new comet.

At the same time, in Stanfield, Arizona, a man named Thomas Bopp was hanging out with some friends who had a telescope, which happened to be pointed at the sky in the same direction as Hale’s. Bopp was not an astronomer but instead a manager at a construction store. He was, however, an amateur stargazer, and knew what to do when he spied the object: the exact same thing Hale had done, which was to check the records to see if this thing had been seen before. It hadn’t. He too understood that he’d discovered a new comet.

In another coincidence–but less amazing, because it’s what you do when you discover something new in the sky–both men did the same thing: they reported what they saw to the Central Bureau for Astronomical Telegrams in Cambridge, Massachusetts. Hale used email, but Bopp, evidently taking the institute’s name literally, sent a Western Union telegram. The CBAT decided that because both men discovered the object at the same time and independently of each other, it should be named after both of them. Thus, the comet was known as Hale-Bopp.

thomas bopp

Thomas Bopp, an amateur astronomer, will forever be known as one of the co-discoverers of the last Great Comet of the 20th century.

Hale-Bopp was an interesting and unusual comet. It’s generally considered one of the “Great Comets,” meaning a comet that could be seen in the sky for a long time with the naked eye. Indeed Hale-Bopp put on quite a show. From its austere beginnings as a smudge in a telescope in the summer of 1995, it hung around for the better part of a year and a half, becoming most prominent in the skies of the Northern Hemisphere during the spring of 1997. Its last recorded appearance with the naked eye was in December of that year, easily outstripping the previous longest visibility of a Great Comet, which was 9 months in 1811-12. Almost everybody could see Hale-Bopp at one time or another. I saw it in the skies over New Orleans, where I was living at the time. It was pretty spectacular.

In addition to being a Great Comet, Hale-Bopp was also somewhat infamous. Great Comets are often thought to be harbingers of doom–the Great Comet of 1861 appeared just before the Civil War, and the 1811 Great Comet is said to have presaged Napoleon’s invasion of Russia. Hale-Bopp had no major wars associated with it, but its appearance did coincide with a marked increase in pseudoscience and “woo” thinking that in the mid-1990s was exploding due to the growing influence of the Internet and “alternative media” talk shows like Art Bell’s Coast to Coast radio program. The purveyors of this sort of stuff latched on to Hale-Bopp and many UFO buffs started talking up the suggestion that there was an extraterrestrial spacecraft following in the tail of the comet. This was rubbish of course, and Alan Hale tried to tamp down this ridiculous suggestion, but to no avail.


Cult leader Marshall Applewhite founded the Heaven’s Gate group in the 1970s. He died together with 38 of his followers in March 1997.

In this case the “woo” had tragic consequences. Heaven’s Gate, a weird UFO cult from Southern California, wove Hale-Bopp into the apocalyptic visions of their leader Marshal Applewhite. In March 1997, as Hale-Bopp was at its most prominent in the sky, 39 members of the cult committed ritual suicide, believing their souls would ascend to the UFO supposedly trailing the comet. Thus, Hale-Bopp is a celestial object with a body count.

Hale-Bopp also left its mark on popular culture. The Heaven’s Gate story is referenced in the movie Contact, which came out in the summer of 1997, which deals with societal reactions to the discovery of extraterrestrial intelligence. The next year a disaster film called Deep Impact loosely adapted the story of Hale-Bopp’s discovery. In the film, a teenage stargazer, played by a pre-Lord of the Rings Elijah Wood, discovers the comet at a class “star party” not unlike the real one where Thomas Bopp made his discovery. He alerts his science teacher, who tells an astronomer (played by Charles Martin Smith), who dies in a car accident shortly thereafter. The comet in the film–which is on a collision course with Earth, naturally–is, like Hale-Bopp, named jointly after its two discoverers, the Elijah Wood character and the astronomer. As if that wasn’t enough, another and much more awful comet-on-collision-with-Earth movie, Michael Bay’s Armageddon, also came out in 1998.

Hale-Bopp was certainly an event, but it’s a very isolated one. Astronomers have calculated that its orbit is so large that it won’t be back to our neighborhood until the year 4385. Its last visit to the central solar system was in 2215 BCE. That certainly was a long time ago, but just to put that in perspective, in 2215 BCE “Ötzi,” the frozen iceman discovered in Italy in 1991 who I profiled on this blog last night, had already been dead for 1,100 years.

The top photo of Comet Hale-Bopp was taken by Michel Benvenuto and Emmanuel Antuna in March 1997. It may be copyrighted; the source of the image is this page. The image of Thomas Bopp is public domain. The image of Marshall Applewhite may be owned by the Heaven’s Gate group. Inclusion of these images here is believed to constitute fair use.