Moonlight
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Moonlight (or Moonshine) is light from the surface of the Moon, consisting mostly of reflected sunlight, and some earthlight.<ref name=Toomer>Template:Cite journal</ref>
History
The ancient Greek philosopher Anaxagoras noted that "the sun provides the moon with its brightness".<ref>Fragment in Plutarch De facie in orbe lunae, 929b, as quoted in "The Riverside Dictionary of Biography" (2005), p. 23</ref> Ancient Chinese polymath Zhang Heng concluded that the light of the moon comes from the Sun. He writes in his treatise, The Spiritual Constitution of the Universe, that the Sun and Moon are "like fire and water", where the Sun "gives out light", and the Moon "reflects it".<ref>Dinwiddie, R., Hughes, D. W., Jackson, T., Johnson, P., Mitton, J. (2017). The Astronomy Book. DK Big Ideas. p.23</ref>
Nyctalopia was called "moonblink" and thought to be caused by sleeping in moonlight in the tropics as late as the 19th century,<ref>Template:Cite book</ref> but is actually caused by a deficiency in Vitamin A. Moonlight was historically thought to cause equine recurrent uveitis, which was called "moon blindness".Template:Cn Moonmilk, a soft white limestone precipitate found in caves, was thought to be caused by the rays of the Moon.<ref name=Gessner>Template:Cite book</ref> Selenoplexia was a supposed medical condition caused by the rays of the moon.<ref name=Lippincott>Lippincott's Medical dictionary (Lippincott, 1906), p. 920.</ref>
Illumination
The color of moonlight appears bluish or silvery to the human eye compared to other, brighter light sources, however this is an illusion, due to the Purkinje effect.Template:Cn The intensity of moonlight varies greatly depending on the lunar phase, with the full moon typically providing about 0.05–0.1 lux illumination.<ref name=supermoon>Template:Cite journal</ref> When a full Moon at perigee (a "supermoon") is viewed around upper culmination from the tropics, the illuminance can reach up to 0.32 lux.<ref name=supermoon/> From Earth, the apparent magnitude of the full Moon is only about Template:Fract that of the Sun.Template:Citation needed The Moon's Bond albedo averages 0.136,<ref name="Saari">Template:Cite journal</ref> meaning only 13.6% of incident sunlight is reflected from the lunar surface. Moonlight takes approximately 1.26 seconds to reach Earth's surface. Moonlight is scattered by particles in the atmosphere of Earth, which increases the brightness of the night sky, and decreases contrast between dimmer stars and the background. For this reason, many astronomers usually avoid observing the sky around a full moon.Template:Cn
Lunar eclipse
A lunar eclipse is an astronomical event that occurs when the Moon moves into the Earth's shadow, causing the moonlight to be darkened.<ref>Template:Cite web</ref> Such an alignment occurs during an eclipse season, approximately every six months, during the full moon phase, when the Moon's orbital plane is closest to the plane of the Earth's orbit.
When the Moon is totally eclipsed by the Earth (a "deep eclipse"),<ref name="QZ-2023">Template:Cite web "What is a deep eclipse? The smaller star is behind the bigger star"</ref><ref name="AT-20231107">Template:Cite news</ref> it takes on a reddish color that is caused by the planet when it completely blocks direct sunlight from reaching the Moon's surface, as the only light that is reflected from the lunar surface is what has been refracted by the Earth's atmosphere. This light appears reddish due to the Rayleigh scattering of blue light, the same reason sunrises and sunsets are more orange than during the day. Template:Clear
Folklore
Moonlight sometimes thought to have a harmful influence in folklore. For example, sleeping in the light of a full moon was believed to transform a person into a werewolf. The light of the Moon was thought to worsen the symptoms of lunatics, and to sleep in moonlight could make one blind, or mad.<ref>A Dictionary of English Folklore, Oxford University Press, 2000</ref>
Art
Template:Further Katie Paterson produced a display at The Guggenheim in 2008, entitled Light bulb to Simulate Moonlight, which consisted of 289 lightbulbs coated to produce a similar spectrum to the light of the full Moon.<ref name=guggenheimPaterson>Template:Cite web</ref>
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Seaport by Moonlight (1771) by Claude Joseph Vernet
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Dovedale by Moonlight (1784) by Joseph Wright of Derby
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Halny (1895) by Stanisław Witkiewicz
Gallery
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Moonlight onto Earth's cloud cover from space
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Moonlight shines on the Very Large Telescope.
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Moonlight illuminates a boat club in Holma, Sweden.
