Supermoons

A supermoon is a full or new moon that occurs when the Moon is at or near its closest point to Earth, a point called perigee. This celestial event happens because the Moon's orbit around Earth is not a perfect circle, but an ellipse. When the full or new moon coincides with perigee, the Moon appears larger and brighter in the sky than an average full or new moon. The term "supermoon" was coined by astrologer Richard Nolle in 1979, though the phenomenon has been observed for centuries.

The visual difference of a supermoon can be subtle to the casual observer, but it can be noticeable. During a supermoon, the Moon can appear up to 14% larger in diameter and up to 30% brighter than when it is at its farthest point from Earth, apogee. This effect is most pronounced when the supermoon is near the horizon, due to the moon illusion, a perceptual phenomenon that makes the Moon appear larger when it is low in the sky.

While supermoons are often associated with increased tidal forces, the effect is minimal. The gravitational pull of the Moon is strongest at perigee, but the difference in tidal range between a supermoon and an average moon is only a few inches. Supermoons do not cause natural disasters, despite some popular misconceptions. They are simply a visually striking alignment of the Sun, Earth, and Moon.