Rare blue moon this Halloween — but it won’t actually be blue

U.S.

FILE – Full moon with visible surface. (Courtesy: Getty Images)

CHICAGO (NewsNation Now) — Keep your eyes to sky! There will be two full moons this October, with one just in time for Halloween.

Specifically, a rare blue moon is forecast for Halloween. But will it really be blue?

“If two full moons happen within the same month, the second is called a blue moon. Doesn’t have anything to do with the color,” clarified NewsNation Chief Meteorologist Albert Ramon. “In October, the second full moon occurs on Halloween.”

“The phrase blue moon has been around for several hundred years. Language changes all the time, so it’s not surprising that the meaning of that phrase has changed during that time, too,” said Michelle Nichols, Director of Public Observing at Adler Planetarium in Chicago. “It originally was a phrase that meant that something was nonsensical.”

On very rare instances the moon may actually appear the color blue according to scientist Martin Mangler at The Natural History Museum in London.

“It can also happen that the moon actually appears a different color than normal,” said Mangler. “So the moonlight we see is reflected light from the sun and if there’s something in the way that blocks the light the can moon can appear blue.”

Mangler said the moon appeared blue to the human eye for over a year due to the 1883 eruption of Indonesian volcano Krakatoa as a result of massive amounts of dust and ash left circulating in the atmosphere.

According to Nichols, atmospheric debris can filter “wavelengths of sunlight” causing “odd-looking sunsets and the moon to appear bluish.”

“Sometimes dust storms and forest fires can also cause the moon to have a blue tint to it,” Nichols said. “But, for the most part, the moon appears whitish or light grayish.”

 According to EarthSky.org this will be “the last full moon to fall on Halloween until October 31, 2039.”

For more Blue Moon trivia you can read how the phrase blue moon changed from “3rd full moon in a season” to “2nd full moon in a calendar month” on the EarthSky website.

NewsNation affiliate WJW contributed to this report.

© 1998 - 2020 Nexstar Inc. | All Rights Reserved.