A rare event in the lunar cycle
This weekend, skywatchers may hear about a rare phenomenon known as the “black moon.” Despite its mysterious name, this event will not produce a visible display in the night sky.
A black moon occurs during the new moon phase, when the Moon is positioned nearly between Earth and the Sun. In this alignment, the illuminated side faces the Sun, while the side facing Earth remains dark, rendering the Moon invisible from the ground.
What does “black moon” mean?
The expression “black moon” is not an official scientific term but is commonly used to describe two scenarios:
- When two new moons happen within the same month.
- When four new moons occur within a single season, with the third being called a “black moon.”
This weekend’s event marks the third new moon of the summer in the Northern Hemisphere. The fourth will take place on September 21, just one day before the autumn equinox, when day and night are nearly equal in length.
What can be seen instead?
Although the black moon itself cannot be observed, this period offers excellent conditions for stargazing. With the Moon absent from the night sky, faint celestial objects become easier to see. One highlight is the Dumbbell Nebula (M27), which appears with a telescope between the stars Altair and Deneb.
When is the next black moon?
The next black moon is expected on August 31, 2027. On that occasion, the event will occur because two new moons will take place in the same calendar month.
