The black moon is occurring this weekend, but it won’t be visible from Earth. Here’s everything you need to know about the celestial event.

A “black moon” is set to rise Saturday, which Hunter Miller, an astronomy educator at the Adler Planetarium, said is most akin to its opposite — a “blue moon.”

The Black Moon refers to the third New Moon in an astronomical season of four New Moons, according to timeanddate.com.