A black moon also refers to the new moon phase itself when the moon is positioned between Earth and the sun, making it nearly invisible from our view. The black moon is a new moon in Capricorn, an Earth sign associated with ambition, professional goals, societal structures and authority, according to Thomas.

Every few years, two new moons occur in the same month - and that is what's known as a black moon. However, as with all new moons, it won't be visible from Earth. Find out more here.

Something rare is happening in the skies in the next few days — a black moon. This rare celestial event is due to an unusual calendar alignment: two new moons in one month. The first occurred on Dec. 1, and now, the second — the black moon — will arrive on Monday, Dec. 30.