Every day brings us closer and closer to the Christmas holiday; and every day Comet 46P/Wirtanen gets closer and closer to Earth. Don’t worry, “The Christmas Comet” is still not going to endanger life on Earth, but this yuletide season brings the celestial body closer to Earth for a spectacular green show in the night sky.
According to University of Maryland’s astronomy department, Comet 46P/Wirtanen’s proximity to Earth actually ranks it among the Earth’s top 10 modern “comet close encounters.” That in mind, NASA Jet Propulsion Laboratory Center for Neart-Earth Object Studies’ manager Paul Chodes comments, “This will be the closest comet Wirtanen has come to Earth for centuries and the closest it will come to Earth for centuries.”
And the comet’s safe distance is still more than 7 million miles away from our planet. Thus, the term “close” is just used to describe our ability to see it with the naked eye (or with some magnification). NASA, then, recommends searching the sky for the constellation Taurus, which is near the Pleiades star cluster. Near this star formation you can find a blur in a familiar Christmas-green shade; and this blur will be moving slowly and steadily across the sky.
Although the comet’s closest approach was Sunday night (which is still about 30 times the distance of our moon), scientists are saying that the comet should continue to be close enough to observe through the rest of the week. Of course, whether or not you are able to see it will depend on sky conditions and the possession of magnification equipment. While a telescope would be quite helpful, even just a pair of standard binoculars should be enough to check it out!
As with other comets, Comet 46P/Wirtanen was named after the person who discovered it. In this case, that person is Carl Wirtanene, who first identified the body streaking across the sky in 1948. The comet is typically pretty bright but its lack of a tail makes it harder to catch than other comets. And while you can only catch it about once every 5.5 years, astronomers have been able to observe it quite reliably—except for one year, when its orbit took it much closer to the sun that we could not see it—and it has been observed and recorded every time we expected to see it.