![Holma Boat Club by the light of the moon](https://upload.wikimedia.org/wikipedia/commons/8/8f/Holma_Boat_Club_by_the_light_of_the_moon.jpg)
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.
History
The ancient Greek philosopher
Anaxagoras
Anaxagoras (; grc-gre, Ἀναξαγόρας, ''Anaxagóras'', "lord of the assembly"; 500 – 428 BC) was a Pre-Socratic Greek philosopher. Born in Clazomenae at a time when Asia Minor was under the control of the Persian Empire, ...
was aware that "''the sun provides the moon with its brightness''".
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
The full moon is the lunar phase when the Moon appears fully illuminated from Earth's perspective. This occurs when Earth is located between the Sun and the Moon (when the ecliptic coordinate system, ecliptic longitudes of the Sun and Moon opp ...
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
An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion.
General description
There are two apsides in any ellip ...
(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 tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in
the Southern Hemisphere at S. The tropics are also referred to ...
, the
illuminance
In photometry, illuminance is the total luminous flux incident on a surface, per unit area. It is a measure of how much the incident light illuminates the surface, wavelength-weighted by the luminosity function to correlate with human brightness ...
can reach up to 0.32 lux.
[ From Earth, the ]apparent magnitude
Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's li ...
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 averages 0.136, meaning only 13.6% 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
The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The atmosphere of Earth protects life on Earth by creating pressure allowing for ...
, moonlight generally increases the brightness
Brightness is an attribute of visual perception in which a source appears to be radiating or reflecting light. In other words, brightness is the perception elicited by the luminance of a visual target. The perception is not linear to luminance, ...
of the night sky
The night sky is the nighttime appearance of celestial objects like stars, planets, and the Moon, which are visible in a clear sky between sunset and sunrise, when the Sun is below the horizon.
Natural light sources in a night sky include ...
, reducing contrast between dimmer stars and the background. For this reason, many astronomer
An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, natural satellite, moons, comets and galaxy, g ...
s 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 a 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
The Very Large Telescope (VLT) is a telescope facility operated by the European Southern Observatory on Cerro Paranal in the Atacama Desert of northern Chile. It consists of four individual telescopes, each with a primary mirror 8.2 m across, ...
.
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 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 ...
, which Earth's atmosphere
The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The atmosphere of Earth protects life on Earth by creating pressure allowing for ...
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
In folklore, a werewolf (), or occasionally lycanthrope (; ; uk, Вовкулака, Vovkulaka), is an individual that can shapeshift into a wolf (or, especially in modern film, a therianthropic hybrid wolf-like creature), either purposely or ...
. 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.
Art
File:Joseph Vernet - Night - Seaport by Moonlight - WGA24731.jpg, ''Seaport by Moonlight'' (1771) by Claude Joseph Vernet
Claude-Joseph Vernet (14 August 17143 December 1789) was a French painter. His son, Antoine Charles Horace Vernet, was also a painter.
Life and work
Vernet was born in Avignon. When only fourteen years of age he aided his father, Antoine 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
Édouard Manet (, ; ; 23 January 1832 – 30 April 1883) was a French modernist painter. He was one of the first 19th-century artists to paint modern life, as well as a pivotal figure in the transition from Realism to Impressionism.
Born ...
File:Van Gogh - Starry Night - Google Art Project.jpg, '' The Starry Night'' (1889) by Vincent van Gogh
Vincent Willem van Gogh (; 30 March 185329 July 1890) was a Dutch Post-Impressionism, Post-Impressionist painter who posthumously became one of the most famous and influential figures in Western art history. In a decade, he created about 2 ...
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 ...
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.
See also
* Airglow
*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 ...
*Diffuse reflection
Diffuse reflection is the reflection (physics), reflection of light or other radiation, waves or particles from a surface such that a ray (optics), ray incident on the surface is scattering, scattered at many angles rather than at just one angle ...
* Earthlight (astronomy)
*Lunar effect
The lunar effect is a purported unproven correlation between specific stages of the roughly 29.5-day lunar cycle and behavior and physiological changes in living beings on Earth, including humans. In some cases the purported effect may depend on ...
*Scotobiology
Scotobiology is the study of biology as directly and specifically affected by darkness, as opposed to photobiology, which describes the biological effects of light.
Overview
The science of scotobiology gathers together under a single descriptive ...
*Starlight
Starlight is the light emitted by stars. It typically refers to visible electromagnetic radiation from stars other than the Sun, observable from Earth at night, although a component of starlight is observable from Earth during daytime.
Sunligh ...
*Night in paintings (Western art)
The depiction of night in paintings is common in Western art. Paintings that feature a night scene as the theme may be religious or history paintings, genre scenes, portraits, landscapes, or other subject types. Some artworks involve religious ...
*Night in paintings (Eastern art)
The depiction of night in paintings is common in art in Asia. Paintings that feature the night scene as the theme are mostly portraits and landscapes. Some artworks which involve religious or fantasy topics use the quality of dim night light to ...
References
External links
Phases of the Moon
at USNO
United States Naval Observatory (USNO) is a scientific and military facility that produces geopositioning, navigation and timekeeping data for the United States Navy and the United States Department of Defense. Established in 1830 as the Depo ...
Strange Moonlight
a
Science@NASA
a
{{Parts of a day
Lunar observation
Light
Light sources