Look into the night sky on 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,” Tony Farnham, a research scientist in the astronomy department at the University of Maryland, said on Saturday morning after a long night studying the comet at the Discovery Channel Telescope, about 40 miles southeast of Flagstaff, Ariz. “You’ve got a one-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.

[Sign up to get reminders for space and astronomy events on your calendar.]