July 2018 lunar eclipse

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A total lunar eclipse occurred on 27 July 2018. The Moon passed through the center of Earth’s shadow in what was the first central lunar eclipse since 15 June 2011. It was also the second total lunar eclipse in 2018, after the one on 31 January.

The eclipse occurred when the Moon was near its maximum distance from Earth, which caused the Moon to appear smaller than normal (a phenomenon sometimes called a micro-moon),[1][2] and to travel at its slowest speed in its orbit around Earth.[3] This was the longest total lunar eclipse that will occur in the 21st century.[3] Totality lasted approximately one hour and 43 minutes,[4][5][6][7] a period “just short of the theoretical limit of a lunar eclipse (one hour and 47 minutes)”.[8] The Moon remained at least partially in Earth’s shadow for four hours.[8]

This lunar eclipse coincided with Mars being nearly as close as possible to Earth, a concurrence that happens once every 25,000 years.[6]

A lunar eclipse occurs when the Moon passes within Earth’s umbra (shadow). As the eclipse begins, Earth’s shadow first darkens the Moon slightly. Then, the Earth’s shadow begins to cover part of the Moon, typically turning it a dark red-brown color (the color can vary based on atmospheric conditions). The Moon appears to be reddish because of Rayleigh scattering (the same effect that causes sunsets to appear reddish and the daytime sky to appear blue) and the refraction of that light by Earth’s atmosphere into its umbra.[9]

The Moon’s brightness is exaggerated within the umbral shadow.[9] The southern portion of the Moon was closest to the center of the shadow, making it the darkest, and most red in appearance.