Trouble sleeping? Blame the "Black Moon"
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Illustration: Allie Carl/Axios
A Black Moon, the rarest of summer Moons, arrives Friday night, and it might keep some people staring at the ceiling.
Why it matters: Scientists have long brushed off connections between the Moon, sleep and mood, but a growing body of research suggests lunar cycles may subtly tug on the circadian rhythms of sensitive individuals — not just during full Moons, but new ones, too.
State of play: "Black Moon" isn't an official astronomy term, according to Earthsky.com, but skywatchers use it similarly to "Blue Moon" when describing the second new Moon in one month or the third of four new Moons in a season.
By the numbers: Seasonal Black Moons, the kind we're seeing now, occur only about once every 33 months, per Space.com.
- The last one was in May 2023, and the next will be in August 2028.
Cases in point: David Avery, professor emeritus at the University of Washington School of Medicine, and other researchers have tracked bipolar patients whose sleep and mood cycles lined up almost perfectly with lunar rhythms.
- One person went sleepless around new and full Moons, tipping into mania, then swung back to 12-hour sleep — and depression — during quarter Moons.
- Another's mood switches tracked spring tides — the periods of strongest gravitational pull that occur at both the new and full Moons — until thyroid treatment and light therapy severed the connection.
Between the lines: Avery tells Axios that moonlight itself isn't to blame.
- Instead, the Moon's subtle gravitational and possible geomagnetic pull may be nudging the body's circadian clock.
- "A lot of people are not aware that the new Moon and full Moon have very similar gravitational effects," Avery said. "We found this applies, too, in people who are not bipolar."
The bottom line: Friday night's invisible Black Moon may be perfect for stargazing, if not for sleeping — with the tail end of the Perseid meteor shower streaking by and a predawn lineup of planets in the east.