A super blue moon captured the attention of millions Aug. 30-31.
A blue moon is the term for when there are two full moons in a single month, according to NASA. The moon’s cycle is 29.5 days, a bit shorter than the average length of a calendar month. Eventually that gap results in a full moon happening at the beginning of a month with enough days still remaining for another full cycle. This happens every two to three years.
The moon travels around the planet in an elliptical orbit, or an elongated circle, with Earth closer to one side of the ellipse.