Coming up later this month (March 19 to be exact) the moon will make its closest approach to Earth (called lunar perigee) in 18 years. A new or full moon at 90% or greater of its closest perigee to Earth has been named a "SuperMoon" by astrologer Richard Nolle. This term has been recently picked up by astronomers. An extreme "SuperMoon" is when the moon is full or new as well as at its 100% greater mean perigee (closest) distance to earth. By this definition, last month's full moon, this month's and next month's will all be extreme "SuperMoons".
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