Thursday, August 30, 2012

Blue Moon

Usually, there is one full moon in every month.  However, occasionally there can be 2 full moons in a month.  This only happens very rarely.  In English, we call the second full moon of the month a Blue Moon*.  Because Blue Moons happen so rarely, we can use the expression "once in a Blue Moon" to mean "only rarely" or "not often."  For example...

I study Japanese once in a Blue Moon.  (It's sad but true!)


John: How often do you go to the movies?

Yoko: Once in a Blue Moon.

This month, there was a full moon on the 2nd.  There will be another full moon tomorrow, August 31st.  Therefore, tomorrow will be a Blue Moon.  Try to do something you don't often do tomorrow.  Once you've done it, you can say, "I only do that once in a Blue Moon!"
*This is a modern definition of Blue Moon dating from 1946.  The traditional definition, which is thousands of years old, is the 3rd full moon of a season with 4 full moons.  Farmers would measure the seasons by counting the full moons.  Usually, it was time to change seasons after 3 full moons.  However, the extra full moon that sometimes happens would confuse them.  They called the 3rd full moon a Belewe Moon.  Belewe is Old English for "liar," that 3rd full moon was a "Liar Moon!"  Somehow, "belewe" was replaced with "blue" in modern English and the original meaning was forgotten.
By the way, Blue Moons are not really blue!  I changed the color of the moon in the above photo using an image-editing program. 

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