July 22 marked the third "supermoon" of 2013, and although it wasn't necessarily as "super" as the one that occurred on June 22-23, it makes you wonder: What is a supermoon, and how often do they occur?
The term "supermoon" was originally coined by astrologer Richard Nolle. It is a shortened form of Super Full Moon, which refers to a full moon that occurs close to or at the same time that the Moon reaches its lunar perigee, or the closest point to Earth in its orbit. When these two events coincide, it can make a full moon appear slightly larger, fuller and brighter than usual.
On average, there is just one supermoon per year, although the full moon before it and the one after it may also be considered a supermoon. In 2013, they occurred on May 24-25 and June 22-23 and July 22-23.
The lunar perigee for this year fell on June 23, making the June 23 the most "super" of the supermoons that occurred in 2013.
The next lunar perigees will fall on Aug. 10, 2014, and Sept. 28, 2015, meaning that any full moon that falls close to those dates will be a candidate for a supermoon.