Blue moon tonight: What does that mean, anyway?
Tuesday night will see a relatively rare phenomenon: A blue moon. What is a blue moon? We'll explain.
MACEDONIA-BLUE-MOON (©AFP/Getty Images)
There's something special about tonight's full moon. If you look up at the night sky, you'll see a rare blue moon. No, it won't actually appear blue, nor is it the second full moon of the month. So what makes it a blue moon?
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Tonight's moon is what's now called a "seasonal blue moon." It's the third full moon in a season that has four, rather than the usual three, according to Space.com. That's actually the original definition of the term, which is thought to come from an Old English word meaning betrayer, because a third full moon usually means the end of a season. Seasonal full moons are rare. Miss this one, and you won't get another chance until May 21, 2016.
Bing: See more photos of the full moon
The other definition of blue moon came about relatively recently. The phrase was first used to describe the second full moon in a calendar month by an amateur astronomer writing for Sky and Telescope magazine in 1946. It was a mistake, but after the phrase was repeated by a syndicated radio program in 1980, the definition stuck. The magazine wrote in 2006 that the modern definition is "like a genie that can't be forced back into its bottle," The Weather Channel reported.
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Of course, there is a third definition, where the moon actually does appear blue in color. To see that, you'd have to live near an erupting volcano. NASA's Tony Phillips said that large particles of ash from an exploding volcano can scatter red light and allow other colors to pass. That would cause white moonbeams to appear blue or sometimes green.
Bing: Read more about tonight's blue moon
Weather permitting, tonight's blue moon will be a beautiful sight. It may not look very different from any other full moon, but then this kind of thing happens only once in a blue moon.
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MSN Photos: What a moon!
What a wonderful definition. Thanks. I must admit I thought the twice in one month was a blue moon. Know I know the rest of the story.
Some of us in Vermont had a wonderful chance to see the moon as the sky was clear on Tuesday night.
It's going to be a nice night for a blue moon; I hope I don't turn in a werewolf or something!
Darn, now I have to do that thing that I do for my husband,....................only once in a blue moon!
Oh, well, like he says, "God told man that he would put women that would cater to them in every corner of the world.............and then he made the world Round." LOL So, I guess we are even!