The Blue Moon

    

     Blue Moon is a term used the second full moon of the calendar month.  Why everybody call this way?

     August 2012 is a month with two full moons and by popular acclaim, this means it’s a Blue Moon month, it is not literally the moon turns into blue, but just a name only.  The first full moon was on August 1st and the second moon this August 31, 2012.

     The time between one full moon and the next is closer to the length of the calendar month. So, the only time one month can have to full moons is when the first moon happens in the first few days of the month. This happens every 2-3 years, so these sorts of Blue Moon come about that often.

      Can there be two blue moons in a single calendar year? Yes, it has happened in 1999. There were two full moons in January and two full moons in March and no full moon in February. So both January and March had blue moons.

      The next year of double blue moons is coming in 2018.