Look into the night sky Sunday and you just might see a bright, fuzzy ball with a greenish-gray tint.
That’s because a comet that orbits between Jupiter and the sun will make its closest approach to Earth in centuries, right on the heels of this year’s most stunning meteor shower.
“The fuzziness is just because it’s a ball of gas basically,” said Tony Farnham, a research scientist in the astronomy department at the University of Maryland. “You’ve got a 1-kilometer solid nucleus in the middle, and gas is going out hundreds of thousands of miles.”
The comet glows green because the gases emit light in green wavelengths.
The ball of gas and dust, sometimes referred to as the “Christmas comet,” was named 46P/Wirtanen, after astronomer Carl Wirtanen, who discovered it in 1948. It orbits the sun once every 5.4 years, passing by Earth approximately every 11 years, but its distance varies and it is rarely this close. As the comet passes by, it will be 30 times farther from Earth than the moon, NASA said.
The proximity of 46P/Wirtanen provides an opportunity to research the tail of the comet and see farther into the nucleus.
“The fact that it’s brighter means we can study a lot of different gas types that we normally can’t study because they’re too faint,” Farnham said, adding that researchers could learn more about where the comet formed and how it evolved.
The comet was visible Saturday, but it will shine even brighter Sunday as it reaches its closest approach, 7.1 million miles from Earth. That may sound really far, but it is among the 10 closest approaches by a comet in 70 years, NASA said. Only a few of those could be seen with the naked eye.
Don’t worry if you miss the comet Sunday. It should be just as visible for a week or two because its appearance will change gradually.
People who live in areas with low levels of light pollution will most likely to be able to see the comet with the naked eye. People who live in cities may need binoculars or a telescope to get a glimpse. Online charts can help pinpoint its location.