On Sunday, December 16th, a tiny comet, Comet Wirtanen (already being dubbed “The Christmas Comet” by social media), is going to pass rather close to our planet. The comet was discovered in 1948 by Carl Wirtanen, an astronomer at California’s Lick Observatory; the comet bears his name. This comet takes about 5½ years to go around the Sun and every so often it passes close to the giant planet Jupiter, whose great gravitational field alters its path in space.
In 1972 and 1984 Jupiter altered Comet Wirtanen’s orbit to such a degree that it started making progressively closer approaches to Earth. And on the 16th it will make one of the ten closest comet approaches to our planet since 1950: just 7.1 million miles away. If Wirtanen’s comet were as large Halley’s Comet we’d be in for a truly spectacular show. Unfortunately, this comet is only about 1/10th as large as Halley’s, so it will appear considerably fainter.
How Can You See Comet Wirtanen?
If you want to see it, you’ll have to travel far away from bright lights, to a dark and starry rural location. Wait until the bright Moon has set late Saturday night/Sunday morning at around 12:30 a.m. EST. Then concentrate your vision to the eastern part of the sky between the Hyades and Pleiades star clusters in Taurus, the Bull. You might perceive a dim, circular ghostly green patch of light roughly the size of the Moon—quite possibly even larger (binoculars will certainly help). That will be the coma, or head of Comet Wirtanen. Don’t expect to see a tail, for any such appendage will likely be very faint. In many ways, it will be an underwhelming sight but considering how unusual a comet comes this close to us, it’s certainly worth a try!