Friday is a blue moon. A blue moon is when there two full moon within one calender month. These happen once every two and half years, and of course led to the saying once in a blue moon. It is even rarer for their to be two blue moons within the same year. This usually happens every nineteen years, the last one being in 1999. This usual happens in January and March because of the short month of February being between them. This is due to the fact the moon takes 29.5 days to go full orbit and therefore can miss February altogether.
August 29, 2012