What is a blue supermoon?

There was a rare, cosmic occurrence in late August. The super blue moon lit up the night sky, capturing people's attention and raising some questions. So what is it? A blue moon is the term for when we see the full moon twice in a single month. Only about 3% of full moons are blue moons, according to NASA. A supermoon is a term for when the moon is closest to Earth. By comparison, the supermoon is much more common-- occurring in about 25% of full moons. But a supermoon that’s also a blue moon? Much more rare. For instance, you'll have to wait until 2037 to see the next one. More LiveNOW from FOX streaming video