Once in a Blue Moon

As we were leaving my parents' house tonight after visiting with my brother and sister-in-law, I noticed how beautiful the moon looked. My mom informed me that tomorrow (New Year's Eve) would be extra special because it would be a blue moon. This means that it is the second full moon in the month, which only happens once every 2.5 years. I actually would have thought it was more rare than that. Now when I say "once in a blue moon", I'll have to think about that meaning only once every 2.5 years... except that that's not the true meaning of blue moon, but we'll get to that later. Another special thing about tomorrow night is that blue moon on New Years Eve only occur every 19 years. Apparently, this definition of "blue moon" only came about as a mistake by a writer for Sky & Telescope magazine, so it is not technically a second full moon of a month but rather the third full moon in a season with four full moons, not the usual three. Confused yet? And I have no idea how often that happens. But blue moon or not, I hope you have a wonderful and safe time ringing in 2010!