Tonight (3-19-11) at around 8PM (MDT), as the Moon is just rising in the east, the Moon will be within a few hours of the place in its orbit where it’s at an unusually close distance to Earth of about 221,000 miles. That’s about 17,000 miles closer to Earth than the overall average Earth-Moon distance, and about 3,000 miles closer than an average perigee “close encounter” distance.
The last time the Moon was this close to Earth was March of 1983.
Visually, tonight’s and tomorrow night’s Moons will appear to be “full” and about 14% bigger and about 30% brighter than an average full moon.
Some folks are promoting this “Super Moon” as a bigger deal than it really is.
Will this Full Moon be brighter than normal? Yes.
Will this Full Moon be bigger than normal? Yes, but you’d have to be a really experienced Moon-watcher to detect the difference with the unaided eye.
Will this Full Moon create havoc and destruction on Earth? No.
The slightly closer-than-average distance between Earth and the Moon means the Moon’s tidal influences on Earth will be about 5% stronger than normal, making for ever-so-slightly higher than average (like an inch or two) tides. Storms at sea create much greater variation in tides than this.
And no, the Moon’s tides didn’t cause the big earthquake in Japan. The Moon was actually farther from Earth than average on the day the quake hit.