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miles) distant. So you can see tonight's moon really is at its closest.
• Did a supermoon cause the 2011 March 11 earthquake in Japan?
• In fact, May 2012 presents the moon's closest encounter with Earth since March 19, 2011, at which time the moon was a scant 380 kilometers closer to Earth. The moon won't come as close as tonight's extra-close moon until August 10, 2014 - although in 2013 the moon at its closest (June 23, 2013) will lie only 36 kilometers farther away than the closest moon in 2012. (See table below) Maybe this helps you see that supermoons - while interesting - are fairly routine astronomical events.
• Even the proximity of full moon with perigee in today's moon isn't all that rare. The extra-close moon in all of these years - 2011, 2012, 2013, 2014 and 2015 - finds the full moon taking place within an hour or so of lunar perigee. More often than not, the closest perigee of the year comes on the day that the full moon and perigee coincide.
• By the way, according to U.S. clocks, the full moon falls this evening at precisely at 10:35 p.m. Central Daylight Time. This same full moon falls tomorrow (Sunday, May 6) at 3:35 Universal Time (UT) - the standard time at the prime meridian of 0o longitude, or, for example, in Greenwich, England.
• How often does the full moon coincide with perigee? Closest full moons recur in cycles of 14 lunar (synodic) months, because 14 lunar months almost exactly equal 15 returns to perigee. A lunar month refers to the time period between successive full moons, a mean period of 29.53059 days. An anomalistic month refers to successive returns to perigee, a period of 27.55455 days. Hence:
• 14 x 29.53059 days = 413.428 days
• 15 x 27.55455 days = 413.318 days
• This time period is equal to about 1 year, 1 month, and 18 days. The full moon and perigee will realign again on June 23, 2013, because the 14th full moon after today's full moon will fall on that date.
• Moon closest to Earth
• Year Date Distance
• 2011 March 19 -356,575 km
• 2012 May 6 -356,955 km
• 2013 June 23 -356,991 km
• 2014 August 10 -356,896 km
• 2015 September 28 -356,877 km
• Looking further into the future, the perigee full moon on November 14, 2016 (356,509 km) will even be closer than the one on March 19, 2011 (356,575 km). The perigee full moon will come closer than 356,500 kilometers for the first time in the

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