Tomorrow night, when the full moon rises over North America, it is believed that this will be a “blue moon.” The modern definition for “blue moon” is the second full moon to occur within a calendar month and tomorrow’s full moon will indeed be the second to occur in the month of May, 2007.
Cartoon Image courtesy of NASA.
But hold on – Sky and Telescope magazine retracted it’s 1946 second-in-a-month definition in favor of stating that the “blue moon” is actually based on the four seasons and is the fourth full moon to occur within a season (Winter, Spring, Summer and Autumn). Using this definition, a “blue moon” may or may not occur within a calendar month.
It gets even more confusing.