The "blue moon" will be visible this Friday, but don't expect to see a change in the color. The name has to do with the rarity. You've probably heard the phrase "once in a blue moon."
Blue moons are defined as either the fourth full moon in a season or the second full moon in a month. Since this month's first full moon was on August 1st, Friday's moon will be known as the "blue moon."
Why do we have two full moons in one month? It takes 29.5 days for the moon to go from new to full again. That's why most months have longer than 29 days (except February).
Blue moons occur 2.7 years apart, but not on a regular basis. For instance, we have a blue moon this month, but the next one won't occur until July 31, 2015.
MORE BLUE MOON FACTS
- A more rare event is when you have 2 blue moons in one year. Last time that happened was in 1999.
- Blue moon originally meant the fourth full moon in a season. Two in one month is a more modern interpretation.
- This year's blue moon will be completely full at 9:58AM this Friday. You may have to do a little searching to spot it, as it will be competing with the rising sun.