The Supermoon Is Coming
Largest full moon of 2013 arrives Sunday
By Kate Seamons,  Newser Staff
Posted Jun 21, 2013 1:18 PM CDT
In this Saturday, May 5, 2012 file photo, a "supermoon" rises behind the Temple of Poseidon in Cape Sounion, Greece, southeast of Athens.   (AP Photo/Dimitri Messinis)
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(Newser) – This weekend will be a little more super than most. That's because the "supermoon" will grace the sky on Sunday. explains why it's so special: At 7am ET, the moon will hit the point in its orbit that's closest to us (ie, reaching "perigee"). At 7:32am ET, the moon will officially be full. The convergence of these events, it explains, gives us the largest full moon of 2013. If you're wondering if this will affect tides, the answer is yes. breaks down the math:

  • At perigee on Sunday, the moon will be 221,824 miles from Earth, which is about 12.2% closer than when the moon is farthest from us (at apogee). "Tidal force varies as the inverse cube of an object's distance." With that 12.2% figure in mind, that means the supermoon "will exert 42% more tidal force at this full moon compared to the spring tides for the full moon that will coincide with apogee next January." ( notes that the high tides may peak as long as two days after the moon reaches perigee.)
Cool, right? Well, at Slate, Phil Plait throws some rain on the supermoon parade: While June 23 will indeed bring the year's biggest moon, "you’d never notice the difference in size or brightness by eye. The full moon will look pretty much like every other full moon you’ve ever seen. Which is to say, big, bright, beautiful, and completely worth your time to go outside and see! But supermoon? Not so much." He explains why here. Or click to read about how supermoon tides reportedly wreaked havoc on ships in 2011.