The University Record, March 25, 1997

Comet Hale-Bopp lights up April sky

April will bring striking views of Comet Hale-Bopp to Michigan sky-watchers, according to astronomer Richard Teske.

Teske recommends looking for the comet about an hour after sunset. "At that hour it should be hanging motionless in the northwest about two hand-breadths above the horizon, its tail extending almost vertically upward," he says. "The comet's head will appear to be a fuzzy star as bright as other stars in that part of the sky." For best results, Teske recommends picking a dark observation site with a low, uncluttered horizon far away from artificial lights.

"Comet Hale-Bopp will remain visible during all of April. For the first two weeks, it will appear about the same altitude above the horizon when darkness descends," Teske says. "After April 15, it will gradually get lower in the sky from night to night. Seen from a good observing site, the tail looks half as long as the handle of the Big Dipper and actually extends over 20 million miles."

Comets are creations of the sun, Teske explains. "A comet's brilliant head, its tail and all of the phenomena we see, are caused by the sun itself. As the comet draws closer to the sun, its head and tail grow more prominent. They fade as the comet recedes from the sun."

The heart and core of every comet is a solid icy fragment of space debris three to eight miles across, the size of a single Earth mountain. This core is made of frozen water, frozen methane and other ices in which gritty, rocky bits are embedded. Space photographs of the nucleus of Comet Halley showed it to be shaped like an Idaho potato. Astronomers believe a huge number of these chunks exist in the dark, deep freeze of space far beyond the farthest planet, Pluto, left over from the formation of our solar system.

"Hale-Bopp will be closest to the sun on April 1 at a distance from it slightly less than our own distance from the sun," Teske says. "That should make April a time of enhanced brightness and tail length and make for a fine comet show."