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| Moon Catcher, Michael P. Ryan |
Those who know me, know that one of the most enchanting things to me in the universe is the moon, especially when it is full. And last night's full moon was particularly special because it was a Blue Moon.
Each month we have a full moon. But every 2-3 years we have two full moons in one month and this is what most people know to be a blue moon. However, last night, November 21, 2010 is the FIRST full moon we've had this month. So what happened? There is another definition of a blue moon that is not as widely known. A moon can be blue when it is the third full moon in a season that has four which would be our moon last night. Confused yet? Here's the story.
Our first definition, two moons in one month, came from a magazine article published in 1946 by "Sky and Telescope" magazine. The article was called "Once in A Blue Moon" by James Hugh Pruett. Using a 1937 Maine Farmer’s Almanac, Pruett basically surmised that 13 full moons a year simply meant that one month had two full moons.
Our second definition goes back a little longer. Back in the Middle Ages the monks followed a seasonal calendar to accurately time their church festivities and ensure the success of their crops. Having 13 moons threw off the dates of their holy days and generally pissed them off. The number 13 became associated as an unlucky number and it is said that the phrase, "Once in a blue moon," came from this.
Following this idea of seasonal moons, the Old Farmer's Almanac later described the blue moon to be the third full moon in a season when there were four. Typically a season will have just 3 full moons, but when there is four, the third is considered to be a blue moon. Why the third moon and not the fourth? Because the last moon in the yearly cycle is traditionally called the "Late Moon."
So when can we expect another blue moon? Going by our first definition - two full moons in one month - the next blue moon will be August 31, 2012. By our second definition, it was last night - November 21, 2010. But stay tuned, in 2018 we will have two double blue moons in one calendar year!
Oh, and just in case you were wondering, the moon is not really blue. Sometimes there are particles of dust or smoke that can make the moon appear to be blue in color.
I can't believe I missed it! This was really interesting to read; I read an article about blue moons sometime last year, and was a little heartbroken to discover that they aren't really blue. ha. So how do you tell the difference between a blue moon and a regular full moon unless you look at the calendar? Do they look any different?
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