This Saturday’s full Moon will be a “super moon”. On May 5th at 10:34 pm St. Louis time, the moon reaches perigee, or the point in its orbit where it is closest to Earth. One minute later, the Moon will line up with the Earth and the Sun to become “full”. The matching up of perigee and the full moon will cause the Moon to look about 14% bigger and 30% brighter than other full Moons this year.
The scientific term for the super moon phenomenon is “perigee moon”. The Moon follows an elliptical, or oblong, path around the Earth. One side of that path is actually closer to the Earth, called perigee. It is a about 50,000 km closer than its opposite, called apogee.
The timing of this “super moon” is even more exact than 2011’s event on March 19th. Perigee and the full moon occurred about an hour apart in that instance, but that moon actually appeared larger than this one will. Before that, the last full moon so big and close occurred in March 1993.
The Eta Aquarid meteor shower is also scheduled for Saturday night. The brightness of the moon will make those meteors hard to see.
The close proximity of the moon does affect the tides, but not by much. The difference between high and low tides may change by about 6 inches.