Science / Medicine : 1987 Goes Down as Year of the Comet

In all the centuries of scanning the skies for comets, astronomers have never had a year like 1987. As of early December, more comets had been spotted in the dark night sky than in any year in the history of astronomy.

“This year we’ve got 33 genuine comets, and we’re not through yet. It’s a record by a large margin,” said Brian Marsden, director of the International Astronomical Union’s Central Telegram Bureau in Cambridge, Mass.

Amateur and professional astronomers found comets last year at an unprecedented rate, first because there were more observers using better equipment and, second, because of a statistical fluke that saw an unusually large number of periodic comets reappear in 1987.

Until now, Marsden said, the largest number of comets ever recorded in one year was 23, in 1983. One of those turned out to be an error, however, so there were actually 22. Of the comets discovered through early December, Marsden said, 17 were “recoveries,” comets that were expected to appear again as their elliptical paths carried them back toward the sun and back into view.

The increase in the number of comets discovered in 1987 can be attributed, in part, to the work of astronomers such as Eugene and Carolyn Shoemaker of Flagstaff, Ariz. Using a relatively small, wide-angle telescope at Mt. Palomar in San Diego County, the Shoemakers can detect comets while still extremely faint and far away. They had discovered three comets for the year through early December, bringing the total catch of comets named “Shoemaker” to 11.