By Laura C. Morel, Boston.com Correspondent

Move over, superman.

A "supermoon" will grace the skies as it rises in the east at sunset tomorrow, according to NASA. It will be the "largest" full moon in 18 years.

The phenomenon occurs when the moon is on the "perigee" part of its elliptical orbit around Earth. During this time, the moon is at its closest proximity to our planet, and thus appears larger.

Although some Internet rumors suggest the upcoming full moon caused the earthquake and tsunami in Japan, NASA reported that, although perigee moons do pull tides in an inch or so higher than usual, they "do not trigger natural disasters."

The best time to view the moon will be tomorrow, when it's near the horizon. But remember, although the moon may appear close, it will still be about 221,567 miles away.

To learn more about the process behind a "supermoon," watch the NASA video above.