What causes the phenomenon of a “blue moon”?
The moon doesn’t look any different when it’s a blue moon. It’s just a calendar thing. Because some of our months have 30 or 31 days, and the moon cycle is about 28 days, every few years a calendar month has 2 full moons in it. That second full moon is known as the Blue Moon. And “once in a blue moon” means something doesn’t happen very often. In 1999, there was a blue moon in January, no full moon in February and a blue moon again in March, which was pretty cool. Depending on what time zone you’re in, there was one this year in either May or June, and the next one is New Year’s Eve, 2009. Sources: I make calendars so I know this kind of stuff.
