Holma Boat Club by the light of the moon

Moonlight consists of mostly

sunlight Sunlight is a portion of the electromagnetic radiation given off by the Sun, in particular infrared, visible, and ultraviolet light. On Earth, sunlight is scattered and filtered through Earth's atmosphere, and is obvious as daylight when t ...

(with little

earthlight ''Earthlight'' is a science fiction novel by British writer Arthur C. Clarke, published in 1955. It is an expansion to novel length of a novella of the same name that he had published four years earlier. Overview ''Earthlight'' is a scie ...

) reflected from the parts of the Moon's surface where the Sun's light strikes.

Illumination

The intensity of moonlight varies greatly depending on the

lunar phase Concerning the lunar month of ~29.53 days as viewed from Earth, the lunar phase or Moon phase is the shape of the Moon's directly sunlit portion, which can be expressed quantitatively using areas or angles, or described qualitatively using the t ...

, but even the full Moon typically provides only about 0.05–0.1

lux The lux (symbol: lx) is the unit of illuminance, or luminous flux per unit area, in the International System of Units (SI). It is equal to one lumen per square metre. In photometry, this is used as a measure of the intensity, as perceived by the ...

illumination. When a full Moon around perigee (a " supermoon") is viewed around upper

culmination In observational astronomy, culmination is the passage of a celestial object (such as the Sun, the Moon, a planet, a star, constellation or a deep-sky object) across the observer's local meridian. These events were also known as meridian transits ...

from the tropics, the illuminance can reach up to 0.32 lux. From Earth, the apparent magnitude of the full Moon is only about that of the Sun. The color of moonlight, particularly around full moon, appears bluish to the

human eye The human eye is a sensory organ, part of the sensory nervous system, that reacts to visible light and allows humans to use visual information for various purposes including seeing things, keeping balance, and maintaining circadian rhythm. ...

compared to other, brighter light sources due to the Purkinje effect. The blue or silver appearance of the light is an illusion. The Moon's bond albedo is 0.12, meaning only 12% of incident sunlight is reflected from the lunar surface. Moonlight takes approximately 1.26 seconds to reach Earth's surface.

Scattered Scattered may refer to: Music * ''Scattered'' (album), a 2010 album by The Handsome Family * "Scattered" (The Kinks song), 1993 * "Scattered", a song by Ace Young * "Scattered", a song by Lauren Jauregui * "Scattered", a song by Green Day from ' ...

in Earth's atmosphere, moonlight generally increases the brightness of the night sky, reducing contrast between dimmer stars and the background. For this reason, many astronomers usually avoid

observing Observation is the active acquisition of information from a primary source. In living beings, observation employs the senses. In science, observation can also involve the perception and recording of data (information), data via the use of scienti ...

sessions around full moon.

Gallery

File:ISS-44 Moon - Goodnight Earth.jpg, Moonlight onto Earth's cloud cover from space File:Sunrise over the VLT.jpg, Moonlight shines on the Very Large Telescope. File:Tonsvatnet, tåke og måne.JPG, Moonlight illuminates a lake and surroundings. File:Giftedtypist - red moon (by).jpg, During a

lunar eclipse A lunar eclipse occurs when the Moon moves into the Earth's shadow. Such 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 ...

, the Moon is colored red by indirect

, which Earth's atmosphere has

scattered Scattered may refer to: Music * ''Scattered'' (album), a 2010 album by The Handsome Family * "Scattered" (The Kinks song), 1993 * "Scattered", a song by Ace Young * "Scattered", a song by Lauren Jauregui * "Scattered", a song by Green Day from ' ...

and refracted. File:Earthshine Moon.jpg,

Earthlight ''Earthlight'' is a science fiction novel by British writer Arthur C. Clarke, published in 1955. It is an expansion to novel length of a novella of the same name that he had published four years earlier. Overview ''Earthlight'' is a scie ...

(indirect sunlight reflected from Earth) illuminates the dim side of the Moon, while direct sunlight the bright side. File:High ISO with long exposure.jpg, With manual exposure settings, photographs taken in moonlight do not appear much different from those taken in

daylight Daylight is the combination of all direct and indirect sunlight during the daytime. This includes direct sunlight, diffuse sky radiation, and (often) both of these reflected by Earth and terrestrial objects, like landforms and buildings. Sunligh ...

Folklore

In folklore, moonlight sometimes has a harmful influence. For example, sleeping in the light of a full Moon on certain nights was said 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.''A Dictionary of English Folklore'', Oxford University Press, 2000

Nyctalopia Nyctalopia (; ), also called night-blindness, is a condition making it difficult or impossible to see in relatively low light. It is a symptom of several eye diseases. Night blindness may exist from birth, or be caused by injury or malnutrition ( ...

(night blindness caused by a lack of vitamin A) was thought to be caused by sleeping in moonlight in the tropics. "

Moon blindness Equine recurrent uveitis (ERU) – also known as moon blindness, recurrent iridocyclitis, or periodic ophthalmia – is an acute, nongranulomatous inflammation of the uveal tract of the eye, occurring commonly in horses of all breeds, wo ...

" is a name for equine recurrent uveitis. Moonlight is no longer thought of as the cause. In the 16th century, moonmilk, a soft white limestone precipitate found in caves, was thought to be caused by the rays of the Moon.

Moonlight in art

File:Joseph Vernet - Night - Seaport by Moonlight - WGA24731.jpg, ''Seaport by Moonlight'' (1771) by Claude Joseph Vernet Image:Joseph Wright of Derby - Dovedale by Moonlight - Google Art Project.jpg, ''

Dovedale by Moonlight Dovedale is a valley in the Peak District of England. The land is owned by the National Trust and attracts a million visitors annually. The valley was cut by the River Dove and runs for just over between Milldale in the north and a wooded r ...

'' (1784) by

Joseph Wright of Derby Joseph Wright (3 September 1734 – 29 August 1797), styled Joseph Wright of Derby, was an English landscape and portrait painter. He has been acclaimed as "the first professional painter to express the spirit of the Industrial Revolution". Wr ...

File:Philippe-Jacques de Loutherbourg - A Philosopher in a Moonlit Churchyard.jpg, ''A Philosopher in a Moonlit

Churchyard In Christian countries a churchyard is a patch of land adjoining or surrounding a church, which is usually owned by the relevant church or local parish itself. In the Scots language and in both Scottish English and Ulster-Scots, this can also ...

'' (1790) by

Philip James de Loutherbourg Philip James de Loutherbourg RA (31 October 174011 March 1812), whose name is sometimes given in the French form of Philippe-Jacques, the German form of Philipp Jakob, or with the English-language epithet of the Younger, was a French-born Brit ...

File:Ed. Manet. Clair de lune sur le port de Boulogne.jpg, '' The Port of Boulogne by Moonlight'' (1869) by Édouard Manet File:Van Gogh - Starry Night - Google Art Project.jpg, '' The Starry Night'' (1889) by Vincent van Gogh File:Stanisław_Witkiewicz_-_Wiatr_halny_1895.jpg, ''Halny'' (1895) by

Stanisław Witkiewicz Stanisław Witkiewicz ( lt, Stanislovas Vitkevičius) (8 May 1851 – 5 September 1915) was a Polish painter, art theoretician, and amateur architect, known for his creation of "Zakopane Style". Life Witkiewicz was born in Poszawsze in S ...

Contemporary art

In 2008

Katie Paterson Katie Paterson (born 1981) is a Fife-based visual artist from Glasgow, Scotland, having previously lived and worked in Berlin whose artworks concern translation, distance, and scale. Paterson holds a BA from Edinburgh College of Art (2004) and an ...

produced an artwork titled ''Light bulb to Simulate Moonlight''. It consists of 289 lightbulbs coated to produce a similar spectrum to the light of the full Moon.

References

External links

Phases of the Moon
at USNO
Strange Moonlight
a
Science@NASA

a

{{Parts of a day Lunar observation Light Light sources Light