Sunday's 'supermoon' won't really drive you mad[ Thu, 20 Jun 2013 23:22:58 GMT ]By Stephanie PappasLiveScience The full moon that will rise Sunday will be the largest of the year, a "supermoon" caused by the slightly asymmetrical orbit of the moon around Earth.A supermoon is a full moon that happens within 12 hours of the lunar perigree, or the point in the lunar orbit that brings the moon closest to Earth. The moon's orbit is slightly elliptical; at its closest approach, the...