Does the length of a full moon vary?

Midget40

The Full Moon is observed when the Sun, Earth, and Moon are in a straight line and the moon's lighted side is behind the Earth in alignment with the sun The moon orbits around the Earth while the moon and Earth system orbits around the sun. The time it takes the Earth to orbit the sun we call one year. Like this cycle, the time it takes the moon to orbit the Earth is called a month. http://www.emporia.edu/earthsci/amber/students/simpler/index.htm This doesn't exactly state it per se but both the moons and the earths orbit remain a constant - thus the time the moon is in the 'full moon' position would have to be the same every month. The only exception to this would be during a lunar eclipse when what we see of the full moon would be shorter. Apr 30 09, 12:36 AM

looney_tunes

Because the orbits are elliptical, the speeds of the orbiting bodies is different at different times, as described by Kepler's Second Law. When the Earth is closer to the Sun in its orbit, its angular speed is greater than when it is further away. The same applies in regards to the Moon in its orbit around the Earth. When these complex motions are combined, the result is that the duration of the 'full moon' phase (and the time between full moons) varies slightly. http://en.wikipedia.org/wiki/Kepler%27s_laws_of_planetary_motion Apr 30 09, 2:15 AM