This weekend, skywatchers in 13 states will experience a celestial rarity—a "black moon." The phenomenon, occurring on Saturday, November 30, will happen only in Western time zones of the United States and Canada.
But what exactly is a black moon and why is it special? Here's everything you need to know.
What Is a Black Moon?
Though not a scientific term used by astronomers, a black moon has two possible definitions.
- Monthly black moon: The second new moon in a single calendar month. This is the more common type and occurs roughly every 29 months.
- Seasonal black moon: The third new moon in a season that contains four new moons. These are less frequent, occurring about once every 33 months.
For this weekend's black moon, the monthly definition applies. Because a lunar cycle lasts 29.5 days, having two new moons in one month is rare but inevitable if the first new moon falls on the first or second day of the month.
"Whether you have two new moons this month depends on your time zone," Darren Baskill, a physics and astronomy lecturer at the University of Sussex in the United Kingdom, told Newsweek. "For the U.K., the next New Moon occurs at 6.21 a.m. (GMT) on the first of December, and for those in the United States that follow eastern or central standard time, the New Moon occurs after midnight, also in December—so neither Europeans, the U.K., nor much of the US will have a second New Moon in November."
But, Baskill said, "for those who follow Pacific or Mountain standard time, the New Moon will occur just before midnight in their local time zone, and so they would have two New Moons in November."
Which States Will Have a Black Moon?
Whether you experience a black moon depends on your time zone. For much of the U.S. and the world, the second new moon will technically occur just after midnight on December 1.
However, in the Pacific, Mountain, Alaska, and Hawaiian time zones, the new moon will occur late in the evening of November 30, marking it as the second new moon in November.
States that will experience this black moon include:
- Mountain Standard Time: Arizona, Colorado, Montana, New Mexico, Utah, Wyoming
- Pacific Standard Time: California, Idaho, Oregon, parts of Nevada, Washington
- Alaska Standard Time: Alaska
- Hawaiian Standard Time: Hawaii
For central and eastern time zones, the black moon will officially occur on December 1.
Why Go Stargazing on a Black Moon?
Though a black moon isn't visible, it creates an ideal stargazing environment. A new moon is when the moon is positioned between Earth and the sun, making it invisible from Earth due to the sun's glare.
With no moonlight to brighten the sky, stargazers can enjoy some of the darkest skies of the month, perfect for observing stars, planets, and deep-sky objects like galaxies and nebulae.
In fact, you don't need to be in one of the states experiencing a black moon to enjoy the skies as the new moon occurs everywhere.
On rare occasions, a new moon is visible in the sky—eclipses. The next partial solar eclipse will occur on March 29, 2025, and will be visible from parts of the U.S., Europe, South America, Africa and Asia.
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