You likely have heard of the term, “once in a blue moon”. That term refers to something that doesn’t happen very often. The term originated from astronomy when you have the second full moon in a calendar month. Typically you only have one full moon during a single calendar month. Though sometimes February won’t have 2 full moons because it’s so short. This month is the rare month that we have 2 full moons in the same calendar month. We had a full moon back on August 1st and now we will have a 2nd on August 31st.
This Friday the full moon time:
August 31, 2012
Because this only happens on average every 2-3 years the term “once in a blue moon” was born. After this months second full moon we won’t see another one until 2015 which is normal. Now the moon won’t actually be blue in color it’s just a term. Though sometimes with certain light conditions the moon can take on a blue tint.
Some astronomers don’t like this definition of a blue moon. The farmers almanac and others refer to a blue moon as the 4th full moon in a single season. If you like that definition this is still a blue moon on Friday as well.