December 2024 will see a rare "black moon," a term for the second new moon in a calendar month. The second new moon of December will occur tonight, at 5:27 p.m. ET (2227 GMT) on Dec. 30, according to the U.S. Naval Observatory, two days after the waning moon passes by Mercury in the predawn sky.

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.