If you see a small, green ball glowing in the sky this holiday season, it’s not Santa getting ready to deliver gifts but Comet 46P/Wirtanen.

The comet – although about 7 million miles away – will make its "closest approach" to Earth for the next two decades, according to NASA.

Additionally, the Geminid meteor shower should also be visible this week for its annual appearance.

Here’s everything to know about the comet and how to see it.

What is the Comet 46P/Wirtanen?

Astronomer Carl Wirtanen first discovered the comet in 1948, according to Space.com.

It is considered to be in the “Jupiter family” of comets.

When will it be visible?

The comet moved closer to the Sun on Dec. 12 and will pass closer to Earth on Dec. 16, according to EarthSky.org.

In the coming years, the comet is expected to be nudged further and further away from Earth, according to Space.com.

“Thus, we can be certain that there can be no very close approach to the Earth ever again. So take full advantage of this upcoming very close encounter!” the site recommends.

How can I see it?

Researchers have said it should be bright enough to view with the naked eye at night on Dec. 16 – although a telescope or binoculars would undoubtedly help. But EarthSky.org warns it “likely will not evolve into a spectacular sight.” Be on the lookout for a “large, diffuse, dim object,” the site adds.

Livestreams are also available from the Virtual Telescope Project.