Perigee.

According to U.S. clocks, May 5, 2012 features the closest and largest full moon of this year. Calendars say May 6, by the way, for this same close full moon as seen from Europe, the Middle East, Africa and Asia. We astronomers call this sort of close full moon a perigee full moon. The word perigee describes the moon’s closest point to Earth for a given month. But last year, when the closest and largest full moon occurred on March 19, 2011, many used a term we’d never heard: supermoon. We’ll probably hear that term again at this 2012 close full moon. What does it mean exactly? And how special is it?

Find out at EarthSky.