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Twilight
Twilight is daylight illumination produced by diffuse sky radiation when the Sun is below the horizon as sunlight from the upper atmosphere is scattered in a way that illuminates both the Earth's lower atmosphere and also the Earth's surface. Twilight also may be any period when this illumination occurs, including dawn and dusk. The lower the Sun is beneath the horizon, the dimmer the sky (other factors such as atmospheric conditions being equal). When the Sun reaches 18° below the horizon, the illumination emanating from the sky is nearly zero, and evening twilight becomes nighttime. When the Sun approaches re-emergence, reaching 18° below the horizon, nighttime becomes morning twilight. Owing to its distinctive quality, primarily the absence of shadows and the appearance of objects silhouetted against the lit sky, twilight has long been popular with photographers and painters, who often refer to it as the blue hour, after the French expression . By analogy with eve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Twilight Description Full Day
Twilight is daylight, daylight illumination produced by diffuse sky radiation when the Sun is below the horizon as sunlight from the upper atmosphere is scattering, scattered in a way that illuminates both the Earth's atmosphere, Earth's lower atmosphere and also the Earth's surface. Twilight also may be any period when this illumination occurs, including dawn and dusk. The lower the Sun is beneath the horizon, the dimmer the sky (other factors such as atmospheric conditions being equal). When the Sun reaches 18° below the horizon, the illumination emanating from the sky is nearly zero, and evening twilight becomes nighttime. When the Sun approaches re-emergence, reaching 18° below the horizon, nighttime becomes morning twilight. Owing to its distinctive quality, primarily the absence of shadows and the appearance of objects silhouetted against the lit sky, twilight has long been popular with photographers and painters, who often refer to it as the blue hour, after the French ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Twilight Toronto Across Lake Ontario51km With Ship5-10km
Twilight is daylight illumination produced by diffuse sky radiation when the Sun is below the horizon as sunlight from the upper atmosphere is scattered in a way that illuminates both the Earth's lower atmosphere and also the Earth's surface. Twilight also may be any period when this illumination occurs, including dawn and dusk. The lower the Sun is beneath the horizon, the dimmer the sky (other factors such as atmospheric conditions being equal). When the Sun reaches 18° below the horizon, the illumination emanating from the sky is nearly zero, and evening twilight becomes nighttime. When the Sun approaches re-emergence, reaching 18° below the horizon, nighttime becomes morning twilight. Owing to its distinctive quality, primarily the absence of shadows and the appearance of objects silhouetted against the lit sky, twilight has long been popular with photographers and painters, who often refer to it as the blue hour, after the French expression . By analogy with evenin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Night
Night, or nighttime, is the period of darkness when the Sun is below the horizon. Sunlight illuminates one side of the Earth, leaving the other in darkness. The opposite of nighttime is daytime. 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 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 about 58 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 the changes brought by nightfall: darkness, increased humidity, and lower temperatures. Their responses include direct reactions a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blue Hour
The blue hour (from French ; ) is the period of twilight (in the morning or evening, around the nautical stage) when the Sun is at a significant depth below the horizon. During this time, the remaining sunlight takes on a mostly blue shade. This shade differs from the colour of the sky on a clear day, which is caused by Rayleigh scattering. The blue hour occurs when the Sun is far enough below the horizon so that the sunlight's blue wavelengths dominate due to the Chappuis absorption caused by ozone. Since the term is colloquial, it lacks an official definition such as dawn, dusk, or the three stages of twilight. Rather, blue hour refers to the state of natural lighting that usually occurs around the nautical stage of the twilight period (at dawn or dusk). The blue hour is shorter in regions near the equator due to the sun rising and setting at steep angles. In places closer to the poles, the illumination and twilight periods are longer as the sun rises and sets at shallower ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crepuscular
In zoology, a crepuscular animal is one that is active primarily during the twilight period, being matutinal (active during dawn), vespertine (biology), vespertine/vespertinal (active during dusk), or both. This is distinguished from diurnality, diurnal and nocturnality, nocturnal behavior, where an animal is active during the hours of daytime and of night, respectively. Some crepuscular animals may also be active by moonlight or during an overcast day. Matutinal animals are active only after dawn, and vespertine (biology), vespertine only before dusk. A number of factors affect the time of day an animal is active. Predation, Predators hunt when their prey is available, and prey try to avoid the times when their principal predators are at large. The temperature may be too high at midday or too low at night. Some creatures may adjust their activities depending on local competition. Etymology and usage The word ''crepuscular'' derives from the Latin ''wiktionary:crepusculum, cre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lighting-up Time
In the United Kingdom, lighting-up time is a legally-enforced period from half an hour after sunset to half an hour before sunrise, during which all motor vehicles on unlit public roads (except if parked) must use their headlights. History Lighting-up time was first introduced in the nineteenth century in local by-laws and enforced nationally by the Lights on Vehicles Act 1907. In the 1920s, Filling station, service stations started displaying cardboard clock-face displays, set to the lighting-up time for the day. The Road Lighting Act 1942 stipulated 1 hour after sunset/before sunrise. It was amended to 30 minutes by the Road Traffic Act 1956 because of the increasing speed of traffic. These were the required times for showing all lights on all vehicles, including bicycles and horse-drawn carts, hence the name ''lighting-up time''. The current Road Vehicles Lighting Regulations 1989 tightened the requirements further. Lighting-up time is retained as the required period f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evening
Evening is the period of a day that begins at the end of daylight and overlaps with the beginning of night. It generally indicates the period of time when the sun is close to the horizon and comprises the periods of civil, nautical and astronomical twilight. The exact times when evening begins and ends are subjective and depend on location and time of year. It may be used colloquially to include the last waning daytime shortly before sunset. Etymology The word is derived from the Old English ''ǣfnung'', meaning 'the coming of evening, sunset, time around sunset', which originated from ''æfnian'', meaning "become evening, grow toward evening". The Old English ''æfnian'' originated from ''æfen'' (eve), which meant "the time between sunset and darkness", and was synonymous with even (Old English ''æfen''), which meant the end of the day. The use of "evening" dates from the mid 15th century. Start time The ''Encyclopædia Britannica'' defines evening as varying according to d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diffuse Sky Radiation
Diffuse sky radiation is solar radiation reaching the Earth's surface after having been scattering, scattered from the direct solar beam by molecules or particulates in the Earth's atmosphere, atmosphere. It is also called sky radiation, the determinative process for changing the colors of the sky. Approximately 23% of direct incident radiation of total sunlight is removed from the direct solar beam by scattering into the atmosphere; of this amount (of incident radiation) about two-thirds ultimately reaches the earth as photon diffusion, photon diffused skylight radiation. The dominant radiative scattering processes in the atmosphere are Rayleigh scattering and Mie scattering; they are elastic scattering, elastic, meaning that a photon of light can be deviated from its path without being absorbed and without changing wavelength. Under an overcast sky, there is no direct sunlight, and all light results from diffused skylight radiation. Proceeding from analyses of the afterm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apparent Magnitude
Apparent magnitude () is a measure of the Irradiance, brightness of a star, astronomical object or other celestial objects like artificial satellites. Its value depends on its intrinsic luminosity, its distance, and any extinction (astronomy), extinction of the object's light caused by interstellar dust along the sightline, line of sight to the observer. Unless stated otherwise, the word ''magnitude'' in astronomy usually refers to a celestial object's apparent magnitude. The magnitude scale likely dates to before the ancient Ancient Greek astronomy#Astronomy in the Greco-Roman and Late Antique eras, Roman astronomer Ptolemy, Claudius Ptolemy, whose Star catalogue, star catalog popularized the system by listing stars from First-magnitude star, 1st magnitude (brightest) to 6th magnitude (dimmest). The modern scale was mathematically defined to closely match this historical system by Norman Robert Pogson, Norman Pogson in 1856. The scale is reverse logarithmic scale, logarithmic: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Burglary
Burglary, also called breaking and entering (B&E) or housebreaking, is a property crime involving the illegal entry into a building or other area without permission, typically with the intention of committing a further criminal offence. Usually that offence is theft, larceny, robbery, or murder, but most jurisdictions include others within the ambit of burglary. To commit burglary is to ''burgle'', a term back-formed from the word ''burglar'', or to ''burglarize''. Etymology Sir Edward Coke (1552–1634) explains at the start of Chapter 14 in the third part of '' Institutes of the Lawes of England'' (pub. 1644), that the word ''Burglar'' ("or the person that committeth burglary"), is derived from the words ''burgh'' and ''laron'', meaning ''house-thieves''. A note indicates he relies on the ''Brooke's case'' for this definition. According to one textbook, the etymology originates from Anglo-Saxon or Old English, one of the Germanic languages. (Perhaps paraphrasing Sir Edward ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
