Rainbows are optical and meteorological phenomena that cause a spectrum of light to appear in the sky when the Sun shines onto droplets of moisture in the Earth's atmosphere. Meteorology (from Greek grc μετέωρος metéōros, "high in the sky" and grc -λογία -logia) is the Interdisciplinary A phenomenon (from Greek φαινόμενoν, pl φαινόμενα - phenomena) is any observable occurrence Light, or visible light, is Electromagnetic radiation of a Wavelength that is visible to the Human eye (about 400–700 The sky is the part of the Atmosphere or of Outer space visible from the surface of any Astronomical object. The Sun (Sol is the Star at the center of the Solar System. Temperature and layers The temperature of the Earth's atmosphere varies with altitude the mathematical relationship between temperature and altitude varies among five They take the form of a multicoloured arc, with red on the outer part of the arch and violet on the inner section of the arch. In Geometry, an arc is a closed segment of a Differentiable Curve in the two-dimensional plane; for example a circular Red is any of a number of similar Colors evoked by light consisting predominantly of the longest wavelengths of Light discernible by the human eye in the wavelength As the name of a color violet (named after the flower violet) is used in two senses first referring to the color of Light at the short- Wavelength More rarely, a secondary rainbow is seen, which is a second, fainter arc, outside the primary arc, with colours in the opposite order, that is, with violet on the outside and red on the inside.
A rainbow spans a continuous spectrum of colours. Traditionally, however, the sequence is quantised. In Digital signal processing, quantization is the process of approximating a continuous range of values (or a very large set of possible discrete values by a relatively-small The most commonly cited and remembered sequence, in English, is Newton's sevenfold red, orange, yellow, green, blue, indigo and violet. Sir Isaac Newton, FRS (ˈnjuːtən 4 January 1643 31 March 1727) Biography Early years See also Isaac Newton's early life and achievements Red is any of a number of similar Colors evoked by light consisting predominantly of the longest wavelengths of Light discernible by the human eye in the wavelength The colour orange occurs Yellow is the Color evoked by light that stimulates both the L and M (long and medium wavelength Cone cells of the Retina about equally Green is a Color, the perception of which is evoked by light having a spectrum dominated by energy with a Wavelength of roughly 520–570- nm. Blue is a Colour, the Perception of which is evoked by Indigo is the Color on the Electromagnetic spectrum between about 420 and 450 nm in Wavelength, placing it between Blue and violet As the name of a color violet (named after the flower violet) is used in two senses first referring to the color of Light at the short- Wavelength "Roy G. Biv" and "Richard Of York Gave Battle In Vain" are popular mnemonics. Roy G Biv is a Mnemonic for the sequence of hues in the Visible spectrum, in rainbows, and in order from longest to shortest wavelength Richard Plantagenet 3rd Duke of York ( 21 September 1411 &ndash 30 December 1460) was a member of the English royal family who served in senior A mnemonic device (nəˈmɒnɪk is a Memory aid Commonly met mnemonics are often verbal something such as a very short poem or a special word used to help a person remember
Rainbows can be caused by other forms of water than rain, including mist, spray, dew, fog, and ice. Moreover, rainbows can have shapes other than a bow (arc), including stripes, circles, or even flames. (See circumhorizontal arc). A circumhorizontal arc or circumhorizon arc ( CHA) also known as a fire rainbow, is a halo or an Optical phenomenon similar in
Rainbows can be observed whenever there are water drops in the air and sunlight shining from behind a person at a low altitude angle (on the ground). Water is a common Chemical substance that is essential for the survival of all known forms of Life. A drop or droplet is a small volume of Liquid, bounded completely or almost completely by Free surfaces Surface tension Sunlight, in the broad sense is the total spectrum of the Electromagnetic radiation given off by the Sun. Altitude is the Elevation of a point or object from a known level or datum (plural data In Geometry and Trigonometry, an angle (in full plane angle) is the figure formed by two rays sharing a common Endpoint, called The most spectacular rainbow displays happen when half of the sky is still dark with draining clouds and the observer is at a spot with clear sky in the direction of the Sun. A cloud is a visible mass of droplets or frozen crystals floating in the atmosphere above the surface of the Earth or another Planetary body The result is a luminous rainbow that contrasts with the darkened background.
The rainbow effect is also commonly seen near waterfalls or fountains. A waterfall is usually a geological formation resulting from water often in the form of a Stream, flowing over an Erosion -resistant rock A traditional fountain is an arrangement where water issues from a source ( Latin fons) fills a basin of some kind and is drained away Rainbow fringes can sometimes be seen at the edges of backlit clouds and as vertical bands in distant rain or virga. Rain is Liquid precipitation. On Earth it is the condensation of atmospheric Water vapor into drops heavy enough to fall often making it to In Meteorology, virga is an observable streak or shaft of precipitation that falls from a Cloud but evaporates before reaching the ground The effect can also be artificially created by dispersing water droplets into the air during a sunny day. Rarely, a moonbow, lunar rainbow or night-time rainbow, can be seen on strongly moonlit nights. moonbow (also known as a lunar rainbow, lunar bow or white rainbow) is a Rainbow produced by the moon rather than the sun Night or nighttime is the period of Time when the Sun is below the Horizon. As human visual perception for colour is poor in low light, moonbows are often perceived to be white. In Psychology, visual perception is the ability to interpret information from Visible light reaching the Eyes The resulting Perception is also 
You can create your own rainbow by facing 180 degrees from the sun and spraying mist from a garden hose in front of you in a circular motion, outlining a 360 degree "rainbow".
It is difficult to photograph the complete arc of a rainbow, as this would require an angle of view of 84°. In Photography, angle of view describes the angular extent of a given scene that is imaged by a Camera. For a 35 mm camera, a lens with a focal length of 19 mm or less would be required, whilst most photographers are only likely to have a 28 mm wide-angle lens. The Millimetre ( American spelling: millimeter, symbol mm) is a unit of Length in the Metric system, equal to From an aeroplane, one has the opportunity to see the whole circle of the rainbow, with the plane's shadow in the centre. Overview Fixed-wing aircraft range from small training and recreational aircraft to Wide-body aircraft and military cargo aircraft. This phenomenon can be confused with the glory, but a glory is usually much smaller, covering only 5°–20°. A glory is an optical phenomenon appearing much like an iconic Saint 's halo about the head of the observer which is produced by light Backscattered (a combination
The rainbow's appearance is caused by dispersion of sunlight as it goes through raindrops. In Optics, dispersion is the phenomenon in which the Phase velocity of a wave depends on its frequency The light is first refracted as it enters the surface of the raindrop, reflected off the back of the drop, and again refracted as it leaves the drop. Refraction is the change in direction of a Wave due to a change in its Speed. Reflection is the change in direction of a Wave front at an interface between two different media so that the wave front returns into the medium from which The overall effect is that the incoming light is reflected back over a wide range of angles, with the most intense light at an angle of 40°–42°. In Geometry and Trigonometry, an angle (in full plane angle) is the figure formed by two rays sharing a common Endpoint, called The angle is independent of the size of the drop, but does depend on its refractive index. The refractive index (or index of Refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves is reduced inside the medium Seawater has a higher refractive index than rain water, so the radius of a 'rain'bow in sea spray is smaller than a true rainbow. This is visible to the naked eye by a misalignment of these bows. 
The amount by which light is refracted depends upon its wavelength, and hence its colour. In Physics wavelength is the distance between repeating units of a propagating Wave of a given Frequency. Blue light (shorter wavelength) is refracted at a greater angle than red light, but because the area of the back of the droplet has a focal point inside the droplet, the spectrum crosses itself, and therefore the red light appears higher in the sky, and forms the outer colour of the rainbow. Blue is a Colour, the Perception of which is evoked by Track listing Child – 516 All I Need – 355 A spectrum (plural spectra or spectrums) is a condition that is not limited to a specific set of values but can vary infinitely within a continuum. Contrary to popular belief, the light at the back of the raindrop does not undergo total internal reflection and some light does emerge from the back. However, light coming out the back of the raindrop does not create a rainbow between the observer and the sun because spectra emitted from the back of the raindrop do not have a maximum of intensity, as the other visible rainbows do, and thus the colours blend together rather than forming a rainbow.
A rainbow does not actually exist at a particular location in the sky. It is an optical illusion whose apparent position depends on the observer's location and the position of the sun. This article is about visual perception See Optical Illusion (Album for information about the Time Requiem album All raindrops refract and reflect the sunlight in the same way, but only the light from some raindrops reaches the observer's eye. This light is what constitutes the rainbow for that observer. The position of a rainbow in the sky is always in the opposite direction of the Sun with respect to the observer, and the interior is always slightly brighter than the exterior (Sometimes full circular rainbow-like light can be observed between the sun and the observer, they are known as a halo solar). A halo (ἅλως also known as a nimbus, icebow or Gloriole) is an Optical phenomenon that appears near or around the Sun or The bow is centred on the shadow of the observer's head, or more exactly at the antisolar point (which is below the horizon during the daytime), appearing at an angle of 40°–42° to the line between the observer's head and its shadow. The antisolar point is the imaginary point on the Celestial sphere exactly opposite the Sun. The horizon ( Ancient Greek ὁ ὁρίζων, /ho horídzôn/ from ὁρίζειν, "to limit" is the apparent line that separates As a result, if the Sun is higher than 42°, then the rainbow is below the horizon and cannot be seen as there are not usually sufficient raindrops between the horizon (that is: eye height) and the ground, to contribute. Exceptions occur when the observer is high above the ground, for example in an aeroplane (see above), on top of a mountain, or above a waterfall. A rainbow can be generated using a garden sprinkler but to get sufficient drops they must be very small.
Occasionally, a second, dimmer, and thicker secondary rainbow is seen outside the primary bow. Secondary rainbows are caused by a double reflection of sunlight inside the raindrops, and appear at an angle of 50°–53°. As a result of the second reflection, the colours of a secondary rainbow are inverted compared to the primary bow, with blue on the outside and red on the inside. The dark area of unlit sky lying between the primary and secondary bows is called Alexander's band, after Alexander of Aphrodisias who first described it. Alexander's band or Alexander's dark band is an Optical phenomenon associated with Rainbows which was named after Alexander of Aphrodisias Alexander of Aphrodisias was the most celebrated of the Ancient Greek commentators on the writings of Aristotle.
A third, or tertiary, rainbow can be seen on rare occasions, and a few observers have reported seeing quadruple rainbows in which a dim outermost arc had a rippling and pulsating appearance. These rainbows would appear on the same side of the sky as the Sun, making them hard to spot. One type of tertiary rainbow carries with it the appearance of a secondary rainbow immediately outside the primary bow. The closely spaced outer bow has been observed to form dynamically at the same time that the outermost (tertiary) rainbow disappears. During this change, the two remaining rainbows have been observed to merge into a band of white light with a blue inner and red outer band. This particular form of doubled rainbow is not like the classic double rainbow due to both spacing of the two bows and that the two bows share identical normal colour positioning before merging. With both bows, the inner colour is blue and the outer colour is red.
Higher-order rainbows were described by Felix Billet (1808-1882) who depicted angular positions up to the 19th-order rainbow. A pattern he called “rose” . In the laboratory, it is possible to observe higher-order rainbows by using extremely bright and well collimated light produced by lasers. Collimated light is Light whose rays are nearly parallel and therefore will spread slowly as it propagates A laser is a device that emits Light ( Electromagnetic radiation) through a process called Stimulated emission. A sixth-order rainbow was first observed by K. Sassan in 1979 using a HeNe laser beam and a pendant water drop. A helium-neon laser, usually called a HeNe laser, is a type of small Gas laser. Up to the 200th-order rainbow was reported by Ng et al. in 1998 using a similar method but an argon ion laser beam .
A supernumerary rainbow is an infrequent phenomenon, consisting of several faint rainbows on the inner side of the primary rainbow, and very rarely also outside the secondary rainbow. Supernumerary rainbows are slightly detached and have pastel colour bands that do not fit the usual pattern.
It is not possible to explain their existence using classical geometric optics. The alternating faint rainbows are caused by interference between rays of light following slightly different paths with slightly varying lengths within the raindrops. In physics interference is the addition ( superposition) of two or more Waves that result in a new wave pattern Some rays are in phase, reinforcing each other through constructive interference, creating a bright band; others are out of phase by up to half a wavelength, cancelling each other out through destructive interference, and creating a gap. The phase of an oscillation or wave is the fraction of a complete cycle corresponding to an offset in the displacement from a specified reference point at time t = 0 In physics interference is the addition ( superposition) of two or more Waves that result in a new wave pattern In physics interference is the addition ( superposition) of two or more Waves that result in a new wave pattern Given the different angles of refraction for rays of different colours, the patterns of interference are slightly different for rays of different colours, so each bright band is differentiated in colour, creating a miniature rainbow. Supernumerary rainbows are clearest when raindrops are small and of similar size. The very existence of supernumerary rainbows was historically a first indication of the wave nature of light, and the first explanation was provided by Thomas Young in 1804. A wave is a disturbance that propagates through Space and Time, usually with transference of Energy. Thomas Young (13 June 1773 &ndash 10 May 1829 was an English Polymath who contributed to the scientific understanding of vision, Light Year 1804 ( MDCCCIV) was a Leap year starting on Sunday (link will display the full calendar of the Gregorian calendar (or a
Other rainbow variants are produced when sunlight reflects off a body of water. Where sunlight reflects off water before reaching the raindrops, it produces a reflection rainbow. Such a rainbow shares the same endpoints as a normal rainbow but encompasses a far greater arc when all of it is visible. Both primary and secondary reflection rainbows can be observed.
A reflected rainbow is produced when light that has first been reflected off a larger body of water then reflects inside raindrops before reaching the observer. [See http://www.eo.ucar.edu/rainbows/rnbw8.gif]
Another rainbow-like variant is produced when sunlight is reflected off clouds. The fire rainbow or circumhorizontal arc can sometimes be seen in cirrus clouds with ice crystals (normally at least 6 km above sea level) and with the sun at least 58° above the horizon. A circumhorizontal arc or circumhorizon arc ( CHA) also known as a fire rainbow, is a halo or an Optical phenomenon similar in
In Song Dynasty China (960–1279), a polymathic scholar-official named Shen Kuo (1031–1095) hypothesized—as a certain Sun Sikong (1015–1076) did before him—that rainbows were formed by a phenomenon of sunlight encountering droplets of rain in the air. The Song Dynasty ( Wade-Giles: Sung Ch'ao was a ruling dynasty in China between 960&ndash1279 CE it succeeded the Five Dynasties and Ten Kingdoms Scholar-bureaucrats or scholar-officials were civil servants appointed by the Emperor of China to perform day-to-day governance from the Sui Dynasty to Shen Kuo or Shen Kua ( (1031&ndash1095 style name Cunzhong and pseudonym Mengqi Weng, was a Polymathic Chinese  Paul Dong writes that Shen's explanation of the rainbow as a phenomenon of atmospheric refraction "is basically in accord with modern scientific principles. Atmospheric Refraction is the deviation of Light or other Electromagnetic wave from a straight line as it passes through the atmosphere due to the "
The Persian astronomer, Qutb al-Din al-Shirazi (1236–1311) gave a fairly accurate explanation for the rainbow phenomenon. layout and formatting it should ensure no clashes with the top of the infobox TemplateInfobox Persian scholars --> Qutb al-Din al-Shirazi (1236 &ndash 1311 (قطبالدین شیرازی was a 13th This was elaborated on by his student, Kamal al-Din al-Farisi (1260–1320), who gave a more mathematically satisfactory explanation of the rainbow. Kamal al-Din Abu'l-Hasan Muhammad Al-Farisi (1267-ca1319/1320 (كمالالدين ابوالحسن محمد فارسی was a prominent Persian Muslim physicist 
In Europe, the work of Robert Grosseteste on light was continued by Roger Bacon, who wrote in his Opus Majus of 1268 about experiments with light shining through crystals and water droplets showing the colours of the rainbow. Robert Grosseteste (c 1175 &ndash October 9, 1253) English statesman scholastic philosopher, Theologian and Bishop of For the Nova Scotia premier see Roger Bacon (politician. Roger Bacon, O The Opus Majus ( Latin for "Greater Work" is the most important work of Roger Bacon.  Theodoric of Freiberg is also known to have given an accurate theoretical explanation of both the primary and secondary rainbows in 1307. Theodoric of Freiberg (c 1250 &ndash c 1310 also known as Thierry of Freiburg, Dietrich of Freiberg, Theodoricus Teutonicus de Vrîberg, or simply He explained the primary rainbow, noting that "when sunlight falls on individual drops of moisture, the rays undergo two refractions (upon ingress and egress) and one reflection (at the back of the drop) before transmission into the eye of the observer".  He explained the secondary rainbow through a similar analysis involving two refractions and two reflections.
Descartes 1637 treatise, Discourse on Method, further advanced this explanation. Organization How to think correctly The Method of Science Morals Maxims deduced from this Method Proof of God and the Soul Physics the heart Knowing that the size of raindrops did not appear to affect the observed rainbow, he experimented with passing rays of light through a large glass sphere filled with water. By measuring the angles that the rays emerged, he concluded that the primary bow was caused by a single internal reflection inside the raindrop and that a secondary bow could be caused by two internal reflections. He supported this conclusion with a derivation of the law of refraction (subsequently, but independently of, Snell) and correctly calculated the angles for both bows. Refraction is the change in direction of a Wave due to a change in its Speed. In Optics and Physics, Snell's law (also known as Descartes' law or the law of refraction) is a formula used to describe the relationship His explanation of the colours, however, was based on a mechanical version of the traditional theory that colours were produced by a modification of white light. 
Isaac Newton was the first to demonstrate that white light was composed of the light of all the colours of the rainbow, which a glass prism could separate into the full spectrum of colours, rejecting the theory that the colours were produced by a modification of white light. Sir Isaac Newton, FRS (ˈnjuːtən 4 January 1643 31 March 1727) Biography Early years See also Isaac Newton's early life and achievements In Optics, a prism is a transparent optical element with flat polished surfaces that refract Light. He also showed that red light gets refracted less than blue light, which led to the first scientific explanation of the major features of the rainbow.  Newton's corpuscular theory of light was unable to explain supernumary rainbows, and a satisfactory explanation was not found until Thomas Young realised that light behaves as a wave under certain conditions, and can interfere with itself. Thomas Young (13 June 1773 &ndash 10 May 1829 was an English Polymath who contributed to the scientific understanding of vision, Light In physics interference is the addition ( superposition) of two or more Waves that result in a new wave pattern
Young's work was refined in the 1820s by George Biddell Airy, who explained the dependence of the strength of the colours of the rainbow on the size of the water droplets. Sir George Biddell Airy FRS (27 July 1801&ndash2 January 1892 was an English Mathematician and Astronomer, Astronomer Royal Modern physical descriptions of the rainbow are based on Mie scattering, work published by Gustav Mie in 1908. Mie theory, also called Lorenz-Mie theory or Lorenz-Mie-Debye theory, is a complete analytical solution of Maxwell's equations for the Scattering Gustav Adolf Feodor Wilhelm Ludwig Mie ( September 29, 1869 Rostock &ndash February 13, 1957 Freiburg im Breisgau) was Advances in computational methods and optical theory continue to lead to a fuller understanding of rainbows. For example, Nussenzveig provides a modern overview. 
The rainbow has a place in legend owing to its beauty and the historical difficulty in explaining the phenomenon. The Rainbow, a natural phenomenon noted for its beauty and inexplicability has been a favorite component of Mythology throughout history
In Greek mythology, the rainbow was considered to be a path made by a messenger (Iris) between Earth and Heaven. Greek mythology is the body of stories belonging to the ancient Greeks concerning their gods and Heroes the nature of the world and the origins and significance In Greek mythology, Iris (Ἴρις is the personification of the Rainbow and messenger of the gods In Chinese mythology, the rainbow was a slit in the sky sealed by Goddess Nüwa using stones of five different colours. Chinese mythology is a collection of Cultural history, Folktales, and Religions that have been passed down in oral or written form In Chinese mythology, Nüwa ( Traditional Chinese: 女媧 Simplified Chinese: 女娲 Pinyin: nǚwā also Nügua is mythological character In Hindu mythology, the rainbow is called Indradhanush, meaning the bow of Indra, the God of lightning and thunder. Hindu mythology is the large body of Mythology related to Hinduism, notably as contained in Sanskrit literature, such as the Sanskrit epics and Indra ( Sanskrit: इन्द्र or इंद्र Indra, Malay: Indera, Thai: พระอินทร์ Phra-Intra Lightning is an atmospheric discharge of Electricity, which typically occurs during Thunderstorms and sometimes during volcanic eruptions or Thunder is the sound made by Lightning. Depending on the nature of the lightning and distance of the listener it can range from a sharp In Norse Mythology, a rainbow called the Bifröst Bridge connects the realms of Ásgard and Midgard, homes of the gods and humans, respectively. Norse mythology comprises the indigenous pre-Christian religion, beliefs and Legends of the Scandinavian peoples including those who settled on Iceland Bifröst ( Old Norse bifrǫst, literally the "tremulous way" from bifask "to tremble" and rǫst "a distance" in This article is about the realm of Norse Mythology For other uses of the names Asgard, Asgaard and Asgård, see Asgard (disambiguation Midgard (an Anglicized form of Old Norse Miðgarðr) is an old Germanic name for our World, the places inhabited by humans, The Irish leprechaun's secret hiding place for his pot of gold is usually said to be at the end of the rainbow. In Irish mythology, a leprechaun (leipreachán Gold (ˈɡoʊld is a Chemical element with the symbol Au (from its Latin name aurum) and Atomic number 79 This place is impossible to reach, because the rainbow is an optical effect which depends on the location of the viewer. When walking towards the end of a rainbow, it will move further away.
After Noah's Deluge, the Bible relates that the rainbow gained new meaning as the sign of God's promise that terrestrial life would never again be destroyed by flood (Genesis 9. The story of a Great Flood (also known as the Deluge) sent by a Deity or deities to destroy Civilization as an act of Divine retribution is a Etymology According to the Online Etymology Dictionary, the word bible is from Latin biblia, traced from the same word through Medieval Latin and Late Latin 13-15):
I have set my bow in the clouds, and it shall be a sign of the covenant between me and the earth. When I bring clouds over the earth and the bow is seen in the clouds, I will remember my covenant that is between me and you and every living creature of all flesh; and the waters shall never again become a flood to destroy all flesh.
Another ancient and accurate portrayal of the rainbow is given in the Epic of Gilgamesh: the rainbow is the literal “jeweled necklace of the Great Mother Ishtar” that she lifts into the sky as a promise that she “will never forget these days of the great flood” that destroyed her children. The Epic of Gilgamesh is an epic poem from Ancient Mesopotamia and is among the earliest known works of literary fiction. Ishtar ( D IŠTAR 𒀭𒌋𒁯 is the Assyrian and Babylonian counterpart to the Sumerian Inanna and to This is an accurate portrayal, as each life-giving droplet of rain could be interpreted as a precious diamond, and when sunlight is refracted through each of these millions of “diamond” prisms, a rainbow is formed. In Mineralogy, diamond is the allotrope of carbon where the carbon atoms are arranged in (The Epic of Gilgamesh, Tablet Eleven)
Then Ishtar arrived. The Epic of Gilgamesh is an epic poem from Ancient Mesopotamia and is among the earliest known works of literary fiction. She lifted up the necklace of great jewels that her father, Anu, had created to please her and said, "Heavenly gods, as surely as this jeweled necklace hangs upon my neck, I will never forget these days of the great flood. Let all of the gods except Enlil come to the offering. Enlil may not come, for without reason he brought forth the flood that destroyed my people. "
The rainbow occurs often in paintings. Frequently these have a symbolic or programmatic significance (for example, Albrecht Dürer's Melancholia I). Albrecht Dürer (ˈalbʀɛçt ˈdyʀɐ ( May 21, 1471 &ndash April 6, 1528) was a German painter, Printmaker Melencolia I, sometimes known as Melancholia I (using the modern spelling is an Engraving by the German Renaissance master Albrecht In particular, the rainbow appears regularly in religious art (for example, Joseph Anton Koch's Noah's Thanksoffering). Joseph Anton Koch ( 27 July 1768 in Elbigenalp – 12 January 1839 in Rome) was an Austrian painter of the German Romantic landscape painters such as Turner and Constable were more concerned with recording fleeting effects of light (for example, Constable's Salisbury Cathedral from the Meadows). Joseph Mallord William Turner (23 April 1775 &ndash 19 December 1851 was an English Romantic landscape painter, Watercolourist and John Constable ( 11 June 1776 &ndash 31 March 1837 Salisbury Cathedral from the Meadows was painted by John Constable in 1829 one year after his wife’s death Other notable examples appear in work by Hans Memling, Caspar David Friedrich, and Peter Paul Rubens. Hans Memling (Memlinc (c 1430 &ndash 11 August, 1494) was an Early Netherlandish painter, born in Seligenstadt / Germany, who Caspar David Friedrich ( September 5, 1774 &ndash May 7, 1840) was a landscape painter of the nineteenth-century German Romantic
Historically, a rainbow flag was used in the German Peasants' War in the 16th century as a sign of a new era, of hope and of social change. A rainbow flag is a multi-colored flag consisting of stripes in the colors of the Rainbow. For other conflicts referred to as peasant wars or revolts see Peasant revolt (disambiguation. Rainbow flags have also been used as a symbol of the Cooperative movement; as a symbol of peace, especially in Italy; to represent the Tawantin Suyu, or Inca territory, in Peru and Ecuador; by some Druze communities in the Middle east; and by the Jewish Autonomous Oblast. Italy (Italia officially the Italian Republic, (Repubblica Italiana is located on the Italian Peninsula in Southern Europe, and on the two largest The Inca Empire (or Inka Empire) was the largest empire in Pre-Columbian America. Peru (Perú Piruw Piruw officially the Republic of Peru ( reˈpuβlika del peˈɾu is a country in western South America. For a topic outline on this subject see List of basic Ecuador topics. The Druze ( Arabic: درزي derzī or durzī, plural دروز durūz) are a religious community found primarily in Syria, Lebanon The Middle East is a Subcontinent with no clear boundaries often used as a synonym to Near East, in opposition to Far East. Jewish Autonomous Oblast (Евре́йская автоно́мная о́бласть Yevreyskaya avtonomnaya oblast) is a federal subject of Russia The rainbow appears on the Gay pride flag, designed by Gilbert Baker for the 1978 San Francisco's Gay Freedom Celebration and today it is often used to represent LGBT-friendly businesses or districts. The Rainbow flag or Pride flag of the LGBT community (also known as the gay pride flag) is a symbol of LGBT pride and LGBT social movements
All the Roy G. Biv mnemonics follow the tradition of including the colour indigo between blue and violet. Roy G Biv is a Mnemonic for the sequence of hues in the Visible spectrum, in rainbows, and in order from longest to shortest wavelength Indigo is the Color on the Electromagnetic spectrum between about 420 and 450 nm in Wavelength, placing it between Blue and violet Blue is a Colour, the Perception of which is evoked by As the name of a color violet (named after the flower violet) is used in two senses first referring to the color of Light at the short- Wavelength Newton originally (1672) named only five primary colours: red, yellow, green, blue and violet. Red is any of a number of similar Colors evoked by light consisting predominantly of the longest wavelengths of Light discernible by the human eye in the wavelength Yellow is the Color evoked by light that stimulates both the L and M (long and medium wavelength Cone cells of the Retina about equally Green is a Color, the perception of which is evoked by light having a spectrum dominated by energy with a Wavelength of roughly 520–570- nm. Blue is a Colour, the Perception of which is evoked by As the name of a color violet (named after the flower violet) is used in two senses first referring to the color of Light at the short- Wavelength Only later did he introduce orange and indigo, giving seven colours by analogy to the number of notes in a musical scale.  Some sources now omit indigo, because it is a tertiary color and partly due to the poor ability of humans to distinguish colours in the blue portion of the visual spectrum. 
There is also some evidence that Newton's use of the terms blue and indigo map to the modern hues cyan and blue respectively. Cyan (saɪæn from Greek κυανός / kyanos, meaning "blue" may be used as the name of any of a number of a range of colors in the blue/green part of 
Since rainbows are composed of a nearly continuous spectrum, different people, most notably across different cultures, identify different numbers of colours in rainbows.