Darkness is the condition resulting from a lack of illumination , or an absence of visible light .
97-512: Night or nighttime is the period of darkness when the Sun is below the horizon . The opposite of nighttime is daytime . Sunlight illuminates one side of the Earth, leaving the other in darkness. Earth's rotation causes the appearance of sunrise and sunset . Moonlight , airglow , starlight , and light pollution dimly illuminate night. The duration of day, night, and twilight varies depending on
194-639: A New Year cleaning tradition), and "reversal" (as in Saturnalia 's slave and master reversals). Some important Neolithic and early Bronze Age archaeological sites in Europe are associated with the winter solstice, such as Stonehenge in England and Newgrange in Ireland. The primary axes of both of these monuments seem to have been carefully aligned on a sight-line pointing to the winter solstice sunrise (Newgrange) and
291-575: A night shift . Nightlife , encompassing bars, nightclubs, and cultural venues, has become a significant part of urban culture, contributing to social and political movements. A planet's rotation causes nighttime and daytime . When a place on Earth is pointed away from the Sun, that location experiences night. The Sun appears to set in the West and rise in the East due to Earth's rotation. Many celestial bodies, including
388-416: A point , on a standard 24-bit computer display , is defined by three RGB (red, green, blue) values, each ranging from 0–255. When the red, green, and blue components of a pixel are fully illuminated (255,255,255), the pixel appears white; when all three components are unilluminated (0,0,0), the pixel appears black. Artists use darkness to emphasize and contrast the presence of light. Darkness can be used as
485-470: A vertebrate , like a human, enters a dark area, its pupils dilate, allowing more light to enter the eye and improving night vision . Also, the light detecting cells in the human eye ( rods and cones ) will regenerate more unbleached rhodopsin when adapting to darkness. One scientific measure of darkness is the Bortle scale , which indicates the night sky's and stars' brightness at a particular location, and
582-894: A vomeronasal organ that enhances their sense of smell. Bats heavily depend on echolocation . Echolocation allows an animal to navigate with their sense of hearing by emitting sounds and listening for the time it takes them to bounce back. Bats emit a steady stream of clicks while hunting insects and home in on prey as thin as human hair. People and other diurnal animals sleep primarily at night. Humans, other mammals, and birds experience multiple stages of sleep visible via electroencephalography . The stages of sleep are wakefulness , three stages of non-rapid eye movement sleep (NREM) including deep sleep , and rapid eye movement (REM) sleep . During REM sleep, dreams are more frequent and complex. Studies show that some reptiles may also experience REM sleep. During deep sleep, memories are consolidated into long-term memory . Invertebrates most likely experience
679-446: A 14th-century Middle English writer of The Canterbury Tales , wrote that knights must cast away the "workes of darkness". In Divine Comedy , Dante described hell as "solid darkness stain'd". In Old English there were three words that could mean darkness: heolstor, genip , and sceadu . Heolstor also meant "hiding-place" and became holster. Genip meant "mist" and fell out of use like many strong verbs . It
776-405: A counterpoint to areas of lightness to create leading lines and voids . Such shapes draw the eye around areas of the painting. Shadows add depth and perspective to a painting. See chiaroscuro for a discussion of the uses of such contrasts in visual media. Color paints are mixed together to create darkness, because each color absorbs certain frequencies of light. Theoretically, mixing together
873-558: A form of sleep as well. Studies on bees, which have complex but unrelated brain structures, have shown improvements in memory after sleep, similar to mammals. Compared to waking life, dreams are sparse with limited sensory detail. Dreams are hallucinatory or bizarre, and they often have a narrative structure. Many hypotheses exist to explain the function of dreams without a definitive answer. Nightmares are dreams that cause distress. The word "night-mare" originally referred to nocturnal demons that were believed to assail sleeping dreamers, like
970-613: A good night." In Ottoman Istanbul , the royal palaces shifted to projecting nocturnal power through large parties lit by lanterns, candles, and fireworks . Though alcohol was forbidden for Muslims , after dark, Turkish Muslims went to the bars and taverns beyond the Muslim areas. The night has long been a time of increased sexual activity, especially in taboo forms such as premarital , extramarital , gay , and lesbian sex. In colonial New England courtship, young unmarried couples practiced bundling before marriage. The couples would lie down in
1067-479: A greater percentage of rod cells. In most mammals, rod cells contain densely packed DNA near the edge of the nucleus. For nocturnal mammals, this is reversed with the densely packed DNA in the center of the nucleus, which reduces the scattering of light. Some nocturnal animals have a mirror, the tapetum lucidum , behind the retina . This doubles the amount of light their eyes can process. The compound eyes of insects can see at even lower levels of light. For example,
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#17330927725121164-459: A major part of the economy and urban planning in modern cities. People who prefer to be active at night are called night owls . Social movements in the 20th century including feminism , black activism, the gay rights movement , and community action blurred the lines between political action and broader cultural activities, making political movements a part of the nightlife. Sociologists have argued that vibrant city nightlife scenes contribute to
1261-509: A metaphor for nocturnal danger. Roman poets like Marcus Manilius and Aratus worked late into the night and incorporated darkness and the night sky into their writing. Since the Age of Enlightenment , nocturnal settings have been a frequent place for passionate chaos as a counterbalance to the rationality present during the day. In Gothic fiction , this absence of rationality offered a space for lust and terror. Ottoman literature portrayed night as
1358-491: A much higher rate. Before the industrial era , night was a time of heightened insecurity. Fear of the night was common but varied in intensity across cultures. Dangers increased due to lower visibility. Injuries and deaths were caused by drowning and falling into pits, ditches, and shafts. People were less able to evaluate others after dark. Due to nocturnal alcohol consumption and the anonymity of darkness, quarrels were more likely to escalate to violence. In medieval Stockholm ,
1455-409: A period of rest and nocturnal labor. Young adults, the urban poor, prostitutes, and thieves benefited from the anonymity of darkness and frequently smashed the new lanterns. Gas lighting was invented in the 1800s. A gas mantle was over ten times brighter than an oil lamp. Gas lighting was associated with the creation of regular police forces. In England, police departments were tasked with maintaining
1552-658: A time for forbidden or unrequited love . Night and day were long depicted as opposite conditions. The electric light, the industrial revolution, and shift work brought many aspects of daily life into the night. The author Charles Dickens lived in London during the time of gas lighting and compared the unstable separation between the waking and sleeping city, to the unstable separation he perceived between dream and delusion. Night in contemporary literature offers liminal settings, such as hospitals and gas stations, that contain some aspects of daily life. Night fell, while Helga Crane in
1649-408: Is Neurospora crassa , a bread mold, widely used to study biorhythms. During the day, plants engage in photosynthesis and release oxygen . By night, plants engage in respiration , consuming oxygen and releasing carbon dioxide. Plants can draw up more water after sunset, which facilitates new leaf growth. As plants cannot create energy through photosynthesis after sunset, they use energy stored in
1746-465: Is embodied by Nótt . Ratri and Nött are goddesses of sleep and rest, but it's common for personifications to be associated with misfortune. In Aztec Mythology, Black Tezcatlipoca , the "Night Wind", was associated with obsidian and the nocturnal jaguar. In his "Precious Owl" manifestation, the Aztecs regarded Tezcatlipoca as the bringer of death and destruction. The Aztecs anticipated an unending night when
1843-531: Is however still used in the Dutch saying " in het geniep " which means secretly. Sceadu meant "shadow" and remained in use. The word dark eventually evolved from the word deorc . Winter solstice The winter solstice , also called the hibernal solstice , occurs when either of Earth 's poles reaches its maximum tilt away from the Sun . This happens twice yearly, once in each hemisphere ( Northern and Southern ). For that hemisphere,
1940-409: Is introduced the creation of light, and the separation of this light from the darkness (as distinct from the creation of the Sun and Moon on the fourth day of creation). Thus, although both light and darkness are included in the comprehensive works of God, darkness was considered "the second to last plague " ( Exodus 10:21), and the location of "weeping and gnashing of teeth" ( Matthew 8:12 ). Erebus
2037-413: Is put to burn in the fire ( zjarri ) of the hearth ( vatër ) on the night of a winter celebration that falls after the return of the Sun for summer (after the winter solstice), sometimes on the night of Kërshëndella on December 24 ( Christmas Eve ), sometimes on the night of kolendra , or sometimes on New Year's Day or on any other occasion aound the same period, a tradition that is originally related to
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#17330927725122134-561: Is said to be dark when it absorbs photons , causing it to appear dim compared to other objects. For example, matte black paint does not reflect much visible light and appears dark, whereas white paint reflects much light and appears bright. For more information, see color . An object may appear dark, but it may be bright at a frequency that humans cannot perceive. A dark area has limited light sources, making things hard to see. Exposure to alternating light and darkness (night and day) has caused several evolutionary adaptations to darkness. When
2231-590: Is the December solstice (December 21, December 22, or December 23) and in the Southern Hemisphere, this is the June solstice (June 20, June 21, or June 22). Although the winter solstice itself lasts only a moment, the term also refers to the day on which it occurs. The term midwinter is also used synonymously with the winter solstice, although it carries other meanings as well. Traditionally, in many temperate regions,
2328-514: Is the only extant Greek tragedy where night is explicitly invoked and made an element of the story. In the play, night is a time of disorder and confusion that allows Odysseus to sneak into the Trojan camp and kill King Rhesus of Thrace . The handful of surviving classical Classical Greek texts that describe the nocturnal activities of women portray female freedom especially to speak openly, male anxieties about that freedom, and magic that functions as
2425-638: The Aztec personification of the Milky Way. The elongated Egyptian goddess Nut and N!adima from Botswana are said to consume the Sun at dusk. In the Ancient Egyptian religion , the Sun then travels through the netherworld inside Nut's body, where it is reborn at dawn. Many cultures have personified the night. Ratri is the star-covered Hindu goddess of the night. In the Icelandic Prose Edda , night
2522-566: The Hindu calendar , in reference to deity Surya (sun). It is observed each year in January. It marks the first day of Sun's transit into Makara (Capricorn) , marking the end of the month with the winter solstice and the start of longer days. Iranian people celebrate the night of the Northern Hemisphere's winter solstice as, " Yalda night ", which is known to be the "longest and darkest night of
2619-534: The Solar System . Mars 's dusty atmosphere causes a lengthy twilight period. The refracted light ranges from purple to blue, often resulting in glowing noctilucent clouds . Venus and Mercury have long nights because of their slow rotational periods. The planet Venus rotates once every 243 Earth days. Because of its unusual retrograde rotation, nights last 116.75 Earth days. The dense greenhouse atmosphere on Venus keeps its surface hot enough to melt lead throughout
2716-453: The Tzitzimīmeh , skeletal female star deities, would descend to consume all humans. In classical mythology, the night goddess Nyx is the mother of Sleep , Death , Disease, Strife , and Doom . In Jewish culture and mysticism , the demon Lilith embodies the emotional reactions to darkness including terror, lust, and liberation. Nighttime in the pre-industrial period, often called
2813-422: The central nervous system of their prey, allowing the fungi to control the actions of the dying insect. During the late afternoon, the fungi will pilot their prey to higher elevation where wind currents can carry its spores further. The fungi will kill and digest the insect as night falls, extending fruiting bodies from the host's exoskeleton. Few species of fungi have true circadian rhythms. A notable exception
2910-572: The elephant hawk moth can see in color, including ultraviolet , with only starlight. Nocturnal insects navigate using moonlight, lunar phases, infrared vision, the position of the stars, and the Earth's magnetic field. Artificial lighting disrupts the biorhythms of many animals. Night-flying insects that use the moon for navigation are especially vulnerable to disorientation from increasing levels of artificial lighting. Artificial lights attract many night-flying insects that die from exhaustion and nocturnal predators. Decreases in insect populations disrupt
3007-590: The incubus (male) or succubus (female). It was believed that the demons could sit upon a dreamer's chest to suffocate a victim, as depicted in John Henry Fuseli's The Nightmare . Fungi can sense the presence and absence of light, and the nightly changes of most fungi growth and biological processes are direct responses to either darkness or falling temperatures. By night, fungi are more engaged in synthesizing cellular components and increasing their biomass. For example, fungi that preys on insects will infect
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3104-522: The loup-garou and rougarou —were believed to be people who transformed into beasts at night. In West Africa and among the African diaspora , there is a widespread tradition of a type of vampire who removes their human skin at night and travels as a blood-sucking ball of light. Variation includes the feu-follet , Surinamese asema , and Caribbean sukuyan , Ashanti obayifo , and Ghanaian asanbosam . The medieval fear of night-flying European witches
3201-619: The talmudic hypothesis that Adam first established the tradition of fasting before the winter solstice , and rejoicing afterward, which festival later developed into the Roman Saturnalia and Kalendae . When the First Man saw that the day was continuously shortening, he said, "Woe is me! Because I have sinned, the world darkens around me, and returns to formlessless and void. This is the death to which Heaven has sentenced me!" He decided to spend eight days in fasting and prayer. When he saw
3298-444: The "night season", was associated with darkness and uncertainty. Various cultures have regarded the night as a time when ghosts and other spirits are active on Earth. When Protestant theologians abandoned the concept of purgatory , many came to view reported ghost sightings as the result of demonic activity. In the sixteenth century, Swiss theologian Ludwig Lavater began attempting to explain reported spirits as mistakes, deceit, or
3395-642: The Christian Haakon had moved Yule from "midwinter" and aligned it with the Christian Christmas celebration. Historically, this has made some scholars believe that Yule originally was a sun festival on the winter solstice. Modern scholars generally do not believe this, as midwinter in medieval Iceland was a date about four weeks after the solstice. During the Christianisation of the Germanic peoples , Yule
3492-453: The Moon always faces the Earth. The side of the Moon facing away from Earth is called the far side of the Moon and the side facing Earth is called the near side of the Moon . During lunar night on the near side, Earth is 50 times brighter than a full moon. Because the Moon has no atmosphere, there is an abrupt transition from day to night without twilight. Night varies from planet to planet within
3589-469: The Roman winter solstice festival marking the sun god's birthday ( Dies Natalis Solis Invicti ). According to C. Philipp E. Nothaft, a professor at Trinity College Dublin , though this theory "is nowadays used as the default explanation for the choice of 25 December as Christ's birthday, few advocates of this theory seem to be aware of how paltry the available evidence actually is." In Anglo-Saxon England
3686-525: The Sun and shorter when a hemisphere is tilted toward the Sun. As a result, the longest night of the year for the Northern Hemisphere will be the shortest night of the year for the Southern Hemisphere . Night's duration varies least near the equator . The difference between the shortest and longest night increases approaching the poles . At the equator, night lasts roughly 12 hours throughout
3783-532: The Sun; the gradual waning of daylight hours is reversed and begins to grow again. Some ancient monuments such as Newgrange , Stonehenge , Cahokia Woodhenge , and Ahu Tongariki are aligned with the sunrise or sunset on the winter solstice. There is evidence that the winter solstice was deemed an important moment of the annual cycle for some cultures as far back as the Neolithic (New Stone Age). Astronomical events were often used to guide farming activities, such as
3880-404: The angular diameter of the Sun. Observing that it occurred within a two-day period is easier, requiring an observation precision of only about 1/16 of the angular diameter of the Sun. Thus, many observations are of the day of the solstice rather than the instant. This is often done by observing sunrise and sunset or using an astronomically aligned instrument that allows a ray of light to be cast on
3977-482: The background. Lower budget films are more likely to use day for night shooting, larger budget films are more likely to film at night with artificial lighting. Cinematographers have used tinting, filters, color balance settings, and physical lights to color night scenes blue. In low light, people experience the Purkinje effect which causes reds to dim so that more blue is perceived. As light decreases towards total darkness,
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4074-576: The birthday of Sol Invictus or the 'Invincible Sun'. Gary Forsythe, Professor of Ancient History, says "This celebration would have formed a welcome addition to the seven-day period of the Saturnalia (December 17–23), Rome's most joyous holiday season since Republican times, characterized by parties, banquets, and exchanges of gifts". A widely-held theory is that the Church chose December 25 as Christ's birthday ( Dies Natalis Christi ) to appropriate
4171-478: The changes brought by nightfall, including darkness, increased humidity, and lower temperatures. Their responses include direct reactions and adjustments to circadian rhythms , governed by an internal biological clock . These circadian rhythms, regulated by exposure to light and darkness, affect an organism's behavior and physiology . Animals more active at night are called nocturnal and have adaptations for low light, including different forms of night vision and
4268-450: The city's marketability but also something to be managed in order to reduce activities viewed as disorderly, risky, or otherwise problematic. Urban renewal policies have increased the available possibilities for nighttime consumers and decreased the non-commercial nocturnal activities outside of sanctioned festivals and concerts. In literature, night is often associated with mysterious, hidden, dangerous, and clandestine activities. Rhesus
4365-526: The cult of the Sun. In East Asia , the winter solstice has been celebrated as one of the Twenty-four Solar Terms , called Dongzhi (冬至) in Chinese . In Japan , in order not to catch cold in the winter, there is a custom to soak oneself in a yuzu hot bath ( Japanese : 柚子湯 = Yuzuyu). Makara Sankranti, also known as Makara Sankrānti ( Sanskrit : मकर संक्रांति) or Maghi, is a festival day in
4462-801: The darkness of night. Light and darkness also affect circadian rhythms, the physical and mental changes that occur in a 24-hour cycle. This daily cycle is regulated by an internal " biological clock " that is adjusted by exposure to light. The length and timing of nighttime depend on location and time of year. Organisms that are more active at night possess adaptations to the night's dimmer light, increased humidity, and lower temperatures. Animals that are active primarily at night are called nocturnal and usually possess adaptations for night vision. In vertebrates' eyes, two types of photoreceptor cells sense light. Cone cells sense color but are ineffective in low light; rod cells sense only brightness but remain effective in very dim light. The eyes of nocturnal animals have
4559-437: The day in black and white. The sections of the monochrome film reel with exterior night scenes were soaked in an acidic dye, that tinted the whole scene blue. " Day for night " is a set of cinematic techniques that simulate a night scene while filming in daylight. They include underexposing to the soften scene, using a graduated neutral-density filter to mute lighting, and setting up the artificial lighting to amplify shadows in
4656-617: The development of culture and political movements. David Grazian cites as examples the development of beat poetry , musical styles including bebop , urban blues , and early rock, and the importance of nightlife for the development of the gay rights movement in the United States kicked off by the riots at the Stonewall Inn nightclub in Greenwich Village , Lower Manhattan , New York City . odern cities treat nightlife as necessary to
4753-457: The difference in day to night temperature shifts increases dramatically. Some exoplanets, like those of TRAPPIST-1 , are tidally locked . Tidally locked planets have equal rotation and orbital periods, so one side experiences constant day, and the other side constant night. In these situations, astrophysicists believe that life would most likely develop in the twilight zone between the day and night hemispheres. Living organisms react directly to
4850-427: The equator, day quickly transitions to night, while the transition can take weeks near the poles. The duration of twilight is longest at the summer solstice and shortest near the equinoxes. Moonlight , starlight , airglow , and light pollution can dimly illuminates the nighttime, with their diffuse aspects being termed skyglow . The amount of skyglow increases each year due to artificial lighting . Night exists on
4947-637: The fields—to return home before the city gates shut. The English engaged in a daily process of "shutting in", where valuables were brought into homes before they were bolted, barred, locked, and shuttered . Many English and European towns attempted to impose curfews during the medieval period and gradually loosened the restrictions via exceptions. Prayer and folk magic were more common by night. Amulets were hung to ward off nightmares, spells were cast against thievery, and pig hearts were hung in chimneys to block demons from traveling down them. The common phrase "good night" has been shortened from "God give you
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#17330927725125044-422: The fire, lighting pine trees at night, luck divination tests with crackling in the fire or with coins in ritual bread, making and consuming ritual foods, performing various magical ritualistic actions in livestock, fields, vineyards and orchards, and so on. Nata e Buzmit, " Yule log 's night", is celebrated between December 22 and January 6. Buzmi is a ritualistic piece of wood (or several pieces of wood) that
5141-438: The gas lights, which became known as "police lamps". Daytime routines were further pushed back into the night by the electric light bulb —invented in the late 19th century—and the widespread usage of newer timekeeping devices like watches. Electric lights created night shifts for traditionally daytime fields, like India's cotton industry, and created opportunities for working adults to attend night school . Before
5238-770: The heightening of other senses. Diurnal animals are active during the day and sleep at night; mammals, birds, and some others dream while asleep. Fungi respond directly to nightfall and increase their biomass. With some exceptions, fungi do not rely on a biological clock. Plants store energy produced through photosynthesis as starch granules to consume at night. Algae engage in a similar process, and cyanobacteria transition from photosynthesis to nitrogen fixation after sunset. In arid environments like deserts, plants evolved to be more active at night, with many gathering carbon dioxide overnight for daytime photosynthesis. Night-blooming cacti rely on nocturnal pollinators such as bats and moths for reproduction. Light pollution disrupts
5335-432: The horizon. During nautical twilight, the horizon is visible enough for navigation. "Astronomical" twilight continues until the Sun has sunk 18 degrees below the horizon. Beyond 18 degrees, refracted sunlight is no longer visible. The period when the sun is 18 or more degrees below either horizon is called astronomical night. Similar to the duration of night itself, the duration of twilight varies according to latitude . At
5432-437: The human eye has more scotopic vision , relying more rod cells and less able to perceive color. Night photography can capture the natural colors of night by increasing the exposure time , or length of time captured in the photography. Longer exposures open the possibility for photographers to use light painting to selectively illuminate a scene. Digital photography can also make use of high-ISO settings , which increase
5529-503: The late evening into the early morning. It has traditionally included venues such as pubs , bars , nightclubs , live music , concerts , cabarets , theatre , Hookah lounges , cinemas , and shows. Nightlife entertainment is often more adult -oriented than daytime entertainment. It also includes informal gatherings like parties , botellón , gymkhanas , bingo , and amateur sports. In many cities, there has been an increasing focus on nightlife catering to tourists. Nightlife has become
5626-631: The limited water availability in arid environments like deserts . The stomata of cacti do not open until night. When the temperature drops, the pores open to allow the cacti to store carbon dioxide for photosynthesis the next day, a process known as crassulacean acid metabolism (CAM). Cacti and most night-blooming plants use CAM to store up to 99% of the carbon dioxide they use in daily photosynthesis. Ceroid cacti often have flowers that bloom at night and fade before sunrise. As few bees are nocturnal, night-flowering plants rely on other pollinators including moths, beetles, and bats. These flowers rely more on
5723-492: The majority of murders were committed while intoxicated. Crime and fear of crime increased at night. In pre-industrial Europe, criminals disguised themselves with hats, face paint, or cloaks . Thieves would trip pedestrians with ropes laid across streets and dismount horse riders using long poles extended from the roadside shadows. They used "dark lanterns" where light could be shined through a single side. Gangs were uncommon except for housebreaking . The increased humidity of night
5820-424: The mating of animals, the sowing of crops and the monitoring of winter reserves of food. The winter solstice was important because the people were economically dependent on monitoring the progress of the seasons. Starvation was common during the first months of the winter, January to April (northern hemisphere) or July to October (southern hemisphere). Livestock were slaughtered so they would not have to be fed during
5917-486: The night sky and the afterlife . Many Native American peoples have described the Milky Way as a path where the deceased travel as stars. The Lakota term for the Milky Way is Wanáǧi Thacháŋku , or "Spirit's Road". In Mayan mythology, the Milky Way's dark band is the Road of Xibalba , the path to the underworld . Unrelated cultures share a myth of a star-covered sky goddess who arches over the planet after sunset, like Citlālicue ,
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#17330927725126014-448: The night," including werewolves , witches , ghosts, and goblins , reflecting societal fears and anxieties. The introduction of artificial lighting extended daytime activities. Major European cities hung lanterns housing candles and oil lamps in the 1600s. Nineteenth-century gas and electric lights created unprecedented illumination. The range of socially acceptable leisure activities expanded, and various industries introduced
6111-407: The night. Its planetary wind system, driven by solar heat, reverses direction from day to night. Venus's winds flow from the equator to the poles on the day side and from the poles to the equator on the night side. On Mercury , the planet closest to the Sun, the temperature drops over 1,000 °F (538 °C) after nightfall. The day-night cycle is one consideration for planetary habitability or
6208-479: The observability of celestial objects at that location. The material known as Vantablack is one of the darkest substances known, absorbing up to 99.965% of visible light (at 663 nm if the light is perpendicular to the material), and was developed by Surrey NanoSystems in the United Kingdom. The name is a compound of the acronym VANTA (vertically aligned nanotube arrays) and the color black. The color of
6305-503: The other planets and moons in the solar system. The length of night is affected by the rotation period and orbital period of the celestial object. The lunar phases visible from Earth result from nightfall on the Moon . The Moon has longer nights than Earth, lasting about two weeks. This is half of the synodic lunar month , the time it takes the Moon to cycle through its phases. The Moon is tidally locked to Earth; it rotates so that one side of
6402-403: The other planets in the solar system, have a form of night. The length of night on Earth varies depending on the time of year. Longer nights occur in winter, with the winter solstice being the longest. Nights are shorter in the summer, with the summer solstice being the shortest. Earth orbits the Sun on an axis tilted 23.44 degrees. Nights are longer when a hemisphere is tilted away from
6499-484: The overall ecosystem because their larvae are a key food source for smaller fish. Dark-sky advocate Paul Bogard described the unnatural migration of night-flying insects from the unlit Nevada desert into Las Vegas as "like sparkling confetti floating in the beam's white column". Some nocturnal animals have developed other senses to compensate for limited light. Many snakes have a pit organ that senses infrared light and enables them to detect heat. Nocturnal mice possess
6596-489: The pagan rites that were practiced by Albanians to celebrate this festivity, but without success. The old rites of this festivity were accompanied by collective fires ( zjarre ) based on the house, kinship or neighborhood, a practice performed in order to give strength to the Sun according to the old beliefs. The rites related to the cult of vegetation, which expressed the desire for increased production in agriculture and animal husbandry, were accompanied by animal sacrifices to
6693-500: The patterns in ecosystems and is especially harmful to night-flying insects. Historically, night has been a time of increased danger and insecurity. Many daytime social controls dissipated after sunset. Theft, fights, murders, taboo sexual activities, and accidental deaths all became more frequent due in part to reduced visibility. Cultures have personified night through deities associated with some or all of these aspects of nighttime. The folklore of many cultures contains "creatures of
6790-518: The plant, typically as starch granules . Plants use this stored energy at a steady rate, depleting their reserves almost right at dawn. Plants will adjust their rate of consumption to match the expected time until sunrise. This avoids prematurely running out of starch reserves, and it allows the plant to adjust for longer nights in the winter. If a plant is subjected to artificially early darkness, it will ration its energy consumption to last until dawn. Succulent plants , including cacti , have adapted to
6887-426: The pole itself, polar night lasts 179 days from September to March. Over a year, there is more daytime than nighttime because of the Sun's size and atmospheric refraction . The Sun is not a single point. Viewed from Earth, the Sun ranges in angular diameter from 31 to 33 arcminutes . When the center of the Sun falls level with the western horizon , half of the Sun will still be visible during sunset. Likewise, by
6984-438: The pollinators' sense of smell with strong perfumes to attract moths and foul-smelling odors to attract bats. Eukaryotic and prokaryotic organisms that engage in photosynthesis are also affected by nightfall. Like plants, algae will switch to taking in oxygen and processing energy stored as starch. Cyanobacteria , also known as blue algae, switch from photosynthesis to nitrogen fixation after sunset, and they absorb DNA at
7081-430: The possibility of extraterrestrial life on distant exoplanets . In general, shorter nights result in a higher equilibrium temperature for the planet. On an Earth-like planet, longer day-night cycles may increase habitability up to a point. Computer models show that longer nights would affect Hadley circulation , resulting in a cooler, less cloudy planet. Once the rotation speed of a planet slows beyond 1/16 that of Earth,
7178-461: The precise timing of its occurrence is now public knowledge. The precise instant of the solstice cannot be directly detected (by definition, people cannot observe that an object has stopped moving until it is later observed that it has not moved further from the preceding spot, or that it has moved in the opposite direction). To be precise to a single day, observers must be able to view a change in azimuth or elevation less than or equal to about 1/60 of
7275-420: The rushing swiftness of a roaring elevated train sat numb. It was as if all the bogies and goblins that had beset her unloved, unloving, and unhappy childhood had come to life with tenfold power to hurt and frighten. Directly filming at night is rarely done. Film stocks and video cameras are much less sensitive to low light environments than the human eye. During the silent film era, night scenes were filmed during
7372-446: The scope of acceptable work and leisure after dark. In the 1600s, the major European cities introduced streetlights. These were lit by lamplighters each evening outside of the summer months. Early street lights were metal and glass enclosures housing candles or oil lamps . They were suspended above streets or mounted on posts. The use of artificial lighting led to an increase in acceptable nightlife. In more rural areas, night remained
7469-519: The sensitivity to light, to take shorter exposure shots. This makes it possible to capture moving subjects without turning their movements into a blur. Darkness Human vision is unable to distinguish colors in conditions of very low luminance because the hue -sensitive photoreceptor cells on the retina are inactive when light levels are insufficient, in the range of visual perception referred to as scotopic vision . The emotional response to darkness has generated metaphorical usages of
7566-402: The sky after sunset and into twilight. There are multiple ways to define twilight, the gradual transition to and from darkness when the Sun is below the horizon. "Civil" twilight occurs when the Sun is between 0 and 6 degrees below the horizon. Nearby planets like Venus and bright stars like Sirius are visible during this period. "Nautical" twilight continues until the Sun is 12 degrees below
7663-446: The term in many cultures, often used to describe an unhappy or foreboding feeling. "Darkness" may also refer to night , which occurs when the Sun is more than 18° below the horizon . The perception of darkness differs from the mere absence of light that sometimes lead to afterimages. In perceiving, the eye is active, and the part of the retina that is unstimulated produces a complementary afterimage. In terms of physics, an object
7760-697: The three primary colors , or the three secondary colors , will absorb all visible light and create black. In practice, it is difficult to prevent the mixture from taking on a brown tint. As a poetic term in the Western world , darkness is used to connote the presence of shadows, evil, and foreboding, or in modern parlance, to connote that a story is grim, heavy, and/or depressing. (Incorrect citation) The first creation narrative in Judaism and Christianity begins with void (not darkness, as originally stated, which means an absence of EVERYTHING including darkness.), into which
7857-466: The time of year and the latitude. Night on other celestial bodies is affected by their rotation and orbital periods . The planets Mercury and Venus have much longer nights than Earth. On Venus, night lasts 120 Earth days. The Moon 's rotation is tidally locked , rotating so that one of the sides of the moon always faces Earth. Nightfall across portions of the near side of the Moon results in lunar phases visible from Earth. Organisms respond to
7954-438: The time the center of the Sun rises to the eastern horizon, half of the Sun will already be visible during sunrise. This shortens night by about 3 minutes in temperate zones . Atmospheric refraction is a larger factor. Refraction bends sunlight over the horizon. On Earth, the Sun remains briefly visible after it has geometrically fallen below the horizon. This shortens night by about 6 minutes. Scattered, diffuse sunlight remains in
8051-406: The widespread usage of artificial lighting, sleep was typically split into two major segments separated by about an hour of wakefulness. During this midnight period, people engaged in prayer, crimes, urination, sex, and, most commonly, reflection. Without exposure to artificial light, studies show that people revert to sleeping in two separate intervals. Diverse cultures have made connections between
8148-412: The winter solstice is the day with the shortest period of daylight and longest night of the year, and when the Sun is at its lowest daily maximum elevation in the sky. Each polar region experiences continuous darkness or twilight around its winter solstice. The opposite event is the summer solstice . The winter solstice occurs during the hemisphere's winter . In the Northern Hemisphere, this
8245-402: The winter solstice is seen as the middle of winter; although today in some countries and calendars it is seen as the beginning of winter. Other names are the "extreme of winter" ( Dongzhi ), or the "shortest day". Since prehistory, the winter solstice has been a significant time of year in many cultures and has been marked by festivals and rites . It marked the symbolic death and rebirth of
8342-463: The winter solstice sunset (Stonehenge). It is significant that at Stonehenge the Great Trilithon was oriented outwards from the middle of the monument, i.e. its smooth flat face was turned towards the midwinter Sun. In the ancient Roman calendar, December 25 was the date of the winter solstice. In AD 274, the emperor Aurelian made this the date of the festival Dies Natalis Solis Invicti ,
8439-637: The winter solstice was generally deemed to be December 25, and in Old English , midwinter could mean both the winter solstice and Christmas . The North Germanic peoples celebrated a winter holiday called Yule . The Heimskringla , written in the 13th century by the Icelander Snorri Sturluson , describes a Yule feast hosted by the Norwegian king Haakon the Good (c. 920–961). According to Snorri,
8536-585: The winter solstice, and he saw that the day was continuously lengthening, he said, "It is the order of the world!" He went and feasted for eight days. The following year, he feasted for both. He established them in Heaven's name, but they established them in the name of idolatry Although the instant of the solstice can be calculated, direct observation of the moment by visual perception is elusive. The Sun moves too slowly or appears to stand still (the meaning of "solstice"). However, by use of astronomical data tracking ,
8633-493: The winter, so it was almost the only time of year when a plentiful supply of fresh meat was available. Because the winter solstice is the reversal of the Sun's apparent ebbing in the sky, in ancient times it was seen as the symbolic death and rebirth of the Sun or of a Sun god . In cultures which used cyclic calendars based on the winter solstice, the "year as reborn" was celebrated with reference to life-death-rebirth deities or "new beginnings" (such as Hogmanay 's redding ,
8730-456: The woman's bed, her family would wrap them tightly with blankets, and they would spend the night together this way. Some families took precautions to prevent unintended pregnancies , like sleeping in the same room, laying a large wooden board between the couple, or pulling a single stocking over both of their daughter's legs. Historian Roger Ekirch described pre-industrial night as a "sanctuary from ordinary existence." Artificial lighting expanded
8827-626: The work of demons. The idea of night as a dangerous, dark, or haunted time persists in modern urban legends like the vanishing hitchhiker . Many times in the night season, there have been certain spirits heard softly going or spitting or groaning, who being asked what they were have made answer that they were the souls of this or that man and that they now endure extreme torments. In folklore, nocturnal preternatural beings like goblins , fairies , werewolves , pucks , brownies , banshees , and boggarts have overlapping but non-synonymous definitions. The werewolf —and its francophone variations
8924-546: The year". Yalda night celebration, or as some call it "Shabe Chelleh" ("the 40th night"), is one of the oldest Iranian traditions that has been present in Persian culture from ancient times. In this night all the family gather together, usually at the house of the eldest, and celebrate it by eating, drinking and reciting poetry (esp. Hafez). Nuts, pomegranates and watermelons are particularly served during this festival. An Aggadic legend found in tractate Avodah Zarah 8a puts forth
9021-435: The year. The tropics have little difference in the length of day and night. At the 45th parallel, the longest winter night is roughly twice as long as the shortest summer night. Within the polar circles , night will last the full 24 hours of the winter solstice. The length of this polar night increases closer to the poles. Utqiagvik, Alaska , the northernmost point in the United States, experiences 65 days of polar night. At
9118-575: Was a primordial deity in Greek mythology , representing the personification of darkness. In Chinese philosophy , yin is the complementary feminine part of the taijitu and is represented by a dark lobe. The use of darkness as a rhetorical device has a long-standing tradition. William Shakespeare, working in the 16th and 17th centuries, made a character called the "prince of darkness" ( King Lear : III, iv) and gave darkness jaws with which to devour love. ( A Midsummer Night's Dream : I, i) Geoffrey Chaucer,
9215-479: Was deemed the result of vapors and fumes. The annual movements of stars and constellations across the night sky were used to track the passage of time, but other changes in the night sky were interpreted as significant omens . Many daytime religious, governmental, and local social controls dissipated after nightfall. Fortified Christian communities announced the coming darkness with horns, church bells , or drums. This alerted residents—like peasants working
9312-616: Was incorporated into the Christmas celebrations and the term and its cognates remain used to refer to Christmas in modern Northern European languages such as English and Swedish. Albanian traditional festivities around the winter solstice celebrate the return of the Sun ( Dielli ) for summer and the lengthening of the days. The Albanian traditional rites during the winter solstice period are pagan, and very ancient. Albanologist Johann Georg von Hahn (1811 – 1869) reported that Christian clergy, during his time and before, have vigorously fought
9409-431: Was influenced by the Roman strix . The Romans described the strix as capable of changing between a beautiful woman and an owl-shaped monster. Common themes among these mythical nocturnal entities include hypersexuality , predation, shapeshifting , deception, mischief, and malice. Nightlife , sometimes referred to as "the night-time economy", is a range of entertainment available and generally more popular from
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