Moonlight - Wikipedia

Light that reaches Earth from the Moon For other uses, see Moonlight (disambiguation).

Moonlight (or moonshine) is light from the surface of the Moon, consisting mostly of reflected sunlight, and some earthlight.[1]

History

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The ancient Greek philosopher Anaxagoras noted that "the sun provides the moon with its brightness".[2] 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".[3]

Nyctalopia was called "moonblink" and thought to be caused by sleeping in moonlight in the tropics as late as the 19th century,[4] but is actually caused by a deficiency in Vitamin A. Moonlight was historically thought to cause equine recurrent uveitis, which was called "moon blindness".[citation needed] Moonmilk, a soft white limestone precipitate found in caves, was thought to be caused by the rays of the Moon.[5] Selenoplexia was a supposed medical condition caused by the rays of the moon.[6]

Illumination

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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: the spectrum has slightly more long-wavelength (red) light than daylight,[7] but is almost the same as that of the sun.[8] The intensity of moonlight varies greatly depending on the lunar phase, with the full moon typically providing about 0.05–0.1 lux illumination.[9] 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.[9] From Earth, the apparent magnitude of the full Moon is only about 1⁄380,000 that of the Sun, and the wavelength pattern is different.[10] The Moon's Bond albedo averages 0.136,[11] 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.[citation needed]

Lunar eclipse

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A lunar eclipse is an astronomical event that occurs when the Moon moves into the Earth's shadow, causing the moonlight to be darkened.[12] 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"),[13][14] 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.

Folklore

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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.[15]

Art

[edit] Further information: Night in paintings (Western art) and Night in paintings (Eastern art)

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.[16]

• Seaport by Moonlight (1771) by Claude Joseph Vernet
• Dovedale by Moonlight (1784) by Joseph Wright of Derby
• Visitor to a Moonlit Churchyard (1790) by Philip James de Loutherbourg
• The Port of Boulogne by Moonlight (1869) by Édouard Manet
• Halny (1895) by Stanisław Witkiewicz

Gallery

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• Moonlight onto Earth's cloud cover from space
• Moonlight shines on the Very Large Telescope.
• Moonlight illuminates a boat club in Holma, Sweden.
• With manual exposure settings, photographs taken in moonlight do not appear much different from those taken in daylight.[8]

See also

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• Airglow
• Daylight
• Diffuse reflection
• Lunar effect
• Scotobiology
• Starlight

References

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1. ^ Toomer, G. J. (December 1964). "Review: Ibn al-Haythams Weg zur Physik by Matthias Schramm". Isis. 55 (4): 463–465 [463–4]. doi:10.1086/349914.
2. ^ Fragment in Plutarch De facie in orbe lunae, 929b, as quoted in "The Riverside Dictionary of Biography" (2005), p. 23
3. ^ Dinwiddie, R., Hughes, D. W., Jackson, T., Johnson, P., Mitton, J. (2017). The Astronomy Book. DK Big Ideas. p.23
4. ^ Smyth, W. H. (1867). The Sailor's Word-Book. Blackie and Son. p. 483. ISBN 0851779727. {{cite book}}: ISBN / Date incompatibility (help)
5. ^ Gessner, Conrad (1555). Descriptio Montis Fracti sive Montis Pilati [Description of Mount Fractus, or Mount Pilatus] (in Latin). p. 54. Retrieved March 12, 2016.
6. ^ Lippincott's Medical dictionary (Lippincott, 1906), p. 920.
7. ^ Barrow, John (2005). The Artful Universe (expanded ed.). New York: Oxford University Press. pp. 208–209.
8. ^ a b Vavilov, S. I. (1965). The Human Eye and Sun - Hot and Cold Light (1st ed.). Oxford: Pergamon Press. p. 102.
9. ^ a b Kyba, Christopher C M; Mohar, Andrej; Posch, Thomas (1 February 2017). "How bright is moonlight?". Astronomy & Geophysics. 58 (1): 1.31–32. doi:10.1093/astrogeo/atx025. Retrieved 14 February 2017.
10. ^ Breitler, J-C.; Djerrab, D.; Leran, S.; Toniutti, L.; Guittin, C.; Severac, D.; Pratlong, M.; Dereeper, A.; Etienne, H.; Bertrand, B. (December 2020). "Full moonlight-induced circadian clock entrainment in Coffea arabica". BMC Plant Biology. 20 (1). doi:10.1186/s12870-020-2238-4.{{cite journal}}: CS1 maint: unflagged free DOI (link)
11. ^ Matthews, Grant (2008). "Celestial body irradiance determination from an underfilled satellite radiometer: application to albedo and thermal emission measurements of the Moon using CERES". Applied Optics. 47 (27): 4981–93. Bibcode:2008ApOpt..47.4981M. doi:10.1364/AO.47.004981. PMID 18806861.
12. ^ McClure, Bruce (27 July 2018). "Century's Longest Lunar Eclipse July 27". EarthSky. Retrieved 1 August 2018.
13. ^ Staff (2023). "PHYS 1350 Astronomy Exam 3 (TXST-Olson)". Quizlet. Retrieved 9 November 2023.{{cite web}}: CS1 maint: deprecated archival service (link) "What is a deep eclipse? The smaller star is behind the bigger star"
14. ^ Miller, A.M.; et al. (7 November 2023). "ATel #16328 - ASASSN-23ht: A Deep Eclipse Event". The Astronomer's Telegram. Retrieved 9 November 2023.{{cite news}}: CS1 maint: deprecated archival service (link)
15. ^ A Dictionary of English Folklore, Oxford University Press, 2000
16. ^ "Katie Paterson Light bulb to Simulate Moonlight". guggenheim.org. Solomon R. Guggenheim Foundation. Retrieved 29 January 2019.

External links

[edit] Wikimedia Commons has media related to Moonlight. Look up moonlight in Wiktionary, the free dictionary.

• Phases of the Moon Archived 2011-07-09 at the Wayback Machine at USNO
• Strange Moonlight at Science@NASA
• Moonlight Brightness at LunarLight Photography

v t e Moon
Outline
Physicalproperties	Internal structure Topography Atmosphere Gravity field Hill sphere Magnetic field Sodium tail Moonlight Earthlight
Orbit	Orbital elements Distance Perigee and apogee Libration Nodes Nodal period Precession Syzygy New moon Full moon Eclipses Lunar eclipse Total penumbral lunar eclipse Tetrad Solar eclipse Solar eclipses on the Moon Eclipse cycle Supermoon Tide Tidal force Tidal locking Tidal acceleration Tidal range Kordylewski clouds Lunar station
Surface andfeatures	Selenography Terminator Limb Hemispheres Near side Far side Poles North pole South pole Face Maria List Mountains Peak of eternal light Valleys Volcanic features Domes Calderas Lava tubes Craters List Ray systems Permanently shadowed craters South Pole–Aitken basin Regolith swirls Rilles Wrinkle ridges Rocks Lunar basalt 70017 Changesite-(Y) Water Space weathering Micrometeorite Sputtering Quakes Transient lunar phenomenon Selenographic coordinate system
Science	Observation Libration Lunar theory Origin Giant-impact hypothesis Theia Lunar magma ocean Geology Timescale Late Heavy Bombardment Lunar meteorites KREEP Volcanism Experiments Lunar laser ranging ALSEP Lunar sample displays Apollo 11 Apollo 17 Lunar seismology
Exploration	Missions Apollo program Explorers Probes Landing Colonization Moonbase Tourism Lunar habitation Lunar resources
Time-telling and navigation	Lunar calendar Lunisolar calendar Month Lunar month Nodal period Fortnight Sennight Lunar station Lunar distance
Phases andnames	New Full Names Crescent Super and micro Blood Blue Black Dark Wet Tetrad
Daily phenomena	Moonrise Meridian passage Moonset
Related	Lunar deities Lunar effect Earth phase Moon illusion Pareidolia Man in the Moon Moon rabbit Craters named after people Artificial objects on the Moon Memorials on the Moon Moon in science fiction list Apollo era futuristic exploration Hollow Moon Moon landing conspiracy theories Moon Treaty "Moon is made of green cheese" Natural satellite Double planet Lilith (hypothetical second moon) Splitting of the Moon
Category

v t e Parts of a day
Daytime	Morning Noon Afternoon
Night	Evening Midnight Witching hour Brahmamuhurta
Twilight	Dawn Sunrise Sunset Dusk Blue hour
Related	Belt of Venus Canonical hours Golden hour Terminator Daylight Moonlight Midnight sun Polar night Watches of the night Zodiacal light