Hi James,

The so-called "Super Moon" that we had last weekend is actually related to the behavior of the Moon's orbit around the Earth. The orbits of the planets around the Sun and the orbit of the Moon around the Earth are not circular. They are actually elliptical, as discovered by the astronomer Joannes Kepler. For the orbit of the Moon (or a man-made satellite) around the Earth, the closest point along the orbit to the Earth is called perigee, and the furthest point away from the Earth along the orbit is called apogee. The full moon on Saturday occurred less than one hour away from the perigee of the Moon's orbit around the Earth. The Moon looked bigger last weekend because it was about 50,000 km (about 31,000 miles) closer to us than it is at apogee.

See these links for more information.

http://science.nasa.gov/s...011/16mar_supermoon/

http://fourmilab.ch/earthview/pacalc.html

Kris