(Photo: By Julio Cortez, AP) Story Highlights The phrase 'Blue Moon' refers to the second blue moon in a month 
 
 The next Blue Moon will not take place until 2015 
 
 The traditional Blue Moon is not really blue, but there have been blue moons 
 
 It's been the motivation for romantic songs and popular phrases, and if you're not doing anything tonight, you should head outside or get yourself to a window so you can see it for yourself. On social media, amateur and professional photographers took advantage of the clear night and snapped and shared photos of the pristine moon against a navy sky. By the way, although tonight's Blue Moon is not actually blue, there have been blue moons in history, according to NOAA. Initially, the phrase referred to the third full moon in a month, but an incorrect explanation in a 1943 edition of Sky and Telescope magazine stuck, according to space.com. The phrase "blue moon" for many people commonly refers to a rare second full moon in a month, although the U.S. This kind of moon appears only once every three years, according to the National Oceanic and Atmospheric Administration.
– Photographers were out in force last night to capture a rare blue moon. No, blue moons aren't actually blue (although there have been moons that were blue, most recently in 1950); rather, the term refers to the second full moon in a month, USA Today reports. But wait, you exclaim! Last night was August's first full moon, so something must be amiss, right? International Science Times clears things up: The first (and, in its telling, "most valid") definition of a blue moon is the third of four full moons that occur in a single season. A season would typically have only three, and this extra moon comes about every two to three years. The next will be in 2015.