A supermoon is the coincidence of a full moon or a new moon with the closest approach the Moon makes to the Earth on its elliptical orbit, resulting in the largest apparent size of the moon’s disk as seen from Earth. Astronomers call this a “perigee full moon.” The perigee full moon happens once every 14 months. This year’s “supermoon” will occur on June 23, 2013. Are you ready?
During a supermoon, the Sun, Earth, and Moon are aligned, where the Earth lies in between the Sun and the Moon. Supermoons, or perigee full moons, appear bigger than usual because they are so close to the Earth. However, on June 23, the moon will be the closer to the Earth and hence it will appear bigger and brighter than usual time. At supermoon time, Moon will be 221,824 miles (356,000 kilometers) away from the Earth, which is roughly 30,000 miles (48,280 kilometers) closer than when it’s at its farthest.
There are a few supermoons every year but the June 2013 full moon is the most super. This full moon falls only 22 minutes after the moons closest approach to earth for 2013. The Moon rises up in the sky on the opposite side of the Sun and the sky watchers can enjoy looking at the supermoon throughout the night from the early hours of the evening until crack of dawn.
The Supermoon size will begin to look smaller as it rises above the sky due to the decreasing distance to Earth. A simple method can be used to check that the Moon’s size is still the same: Stretch an arm and hold out the thumb up to the Moon then close one eye to observe that the thumb still covers the size of the Moon or not.
According to science news site EarthSky, a full moon will not be as close to the Earth again until August 2014.