A rare Halloween blue moon has been thrilling skywatchers across the globe.
The last time a blue moon occurred on Halloween was in 2001, according to the Farmer's Almanac, and will not happen again until 2039.
As the second full moon of the month, it is classified as a blue moon. “In recent years, people have been using the name Blue moon for the second of two full moons in a single calendar month,” NASA explains on its website. “An older definition of Blue moon is that it’s the third of four full moons in a single season.”
BLUE MOON TO APPEAR ON HALLOWEEN FOR THE FIRST TIME IN NEARLY 20 YEARS
The month’s other full moon, the “harvest moon,” occurred Oct. 1. Old Farmer’s Almanac notes that the harvest moon is the full moon closest to the beginning of fall or the autumnal equinox.
A rare Halloween blue moon moon rises over a bank of lights at Falcon Stadium in the second half of an NCAA college football game between Air Force and Boise State, Saturday, Oct. 31, 2020, at Air Force Academy, Colo. (Associated Press)
Skygazers, however, should not expect the Halloween blue moon to be, well … blue. “Most Blue Moons look pale gray and white, indistinguishable from any other Moon you've ever seen,” NASA explains.
The term “blue moon” evolved to denote something that is absurd, according to Space.com, citing Philip Hiscock, a folklorist at the Memorial University of Newfoundland, in a 2012 article in Sky & Telescope magazine.
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The full moon rises over the outskirts of Frankfurt, Germany, Saturday, Oct. 31, 2020. The full moon is known as a Blue moon. (Associated Press)
In rare circumstances, however, the moon can look blue. “A truly-blue Moon usually requires a volcanic eruption,” explains NASA. “Back in 1883, for example, people saw blue moons almost every night after the Indonesian volcano Krakatoa exploded with the force of a 100-megaton nuclear bomb. Plumes of ash rose to the very top of Earth's atmosphere, and the Moon … it turned blue!”
Fox News’ Chris Ciaccia contributed to this story. Follow James Rogers on Twitter @jamesjrogers
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