Perigee Moon, Largest of 2010

14% wider and 30% brighter than other full moons of the year. Johannes Kepler explained the phenomenon 400 years ago. The Moon's orbit around Earth is not a circle; it is an ellipse, with one side 50,000 km closer to Earth than the other. Astronomers call the point of closest approach "perigee," and that is where the moon is tonight.