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SKYGLOW
Skyglow (or sky glow) is the diffuse luminance of the night sky, apart from discrete light sources such as the Moon and visible individual stars. It is a commonly noticed aspect of light pollution. While usually referring to luminance arising from artificial lighting, skyglow may also involve any scattered light seen at night, including natural ones like starlight, zodiacal light, and airglow. In the context of light pollution, skyglow arises from the use of artificial light sources, including electrical (or rarely gas) lighting used for illumination and advertisement and from gas flares. Light propagating into the atmosphere directly from upward-directed or incompletely shielded sources, or after reflection from the ground or other surfaces, is partially scattered back toward the ground, producing a diffuse glow that is visible from great distances. Skyglow from artificial lights is most often noticed as a glowing dome of light over cities and towns, yet is pervasive through ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light Pollution
Light pollution is the presence of any unwanted, inappropriate, or excessive artificial Visible spectrum, lighting. In a descriptive sense, the term ''light pollution'' refers to the effects of any poorly implemented lighting sources, during the day or night. Light pollution can be understood not only as a phenomenon resulting from a specific source or kind of pollution, but also as a contributor to the wider, collective impact of various sources of pollution. Although this type of pollution can exist throughout the day, its effects are magnified during the night with the contrast of the sky's darkness. It has been estimated that 83% of the world's people live under light-polluted skies and that 23% of the world's land area is affected by skyglow. The area affected by artificial illumination continues to increase. A major side effect of urbanization, light pollution is blamed for compromising health, disrupting ecosystems, and spoiling aesthetic environments. Studies show that ur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 moonlight, starlight, and airglow, depending on location and timing. Aurorae light up the skies above the polar circles. Occasionally, a large coronal mass ejection from the Sun or simply high levels of solar wind may extend the phenomenon toward the Equator. The night sky and studies of it have a historical place in both ancient and modern cultures. In the past, for instance, farmers have used the status of the night sky as a calendar to determine when to plant crops. Many cultures have drawn constellations between stars in the sky, using them in association with legends and mythology about their deities. The history of astrology has generally been based on the belief that relationships between heavenly bodies influence or explain events on Ear ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Airglow
Airglow is a faint emission of light by a planetary atmosphere. In the case of Earth's atmosphere, this optical phenomenon causes the night sky never to be completely dark, even after the effects of starlight and diffuse sky radiation, diffused sunlight from the far side are removed. This phenomenon originates with self-illuminated gases and has no relationship with Earth's magnetic field, Earth's magnetism or sunspot activity, causing aurorae. Airglow occurs in two forms, resulting by two different processes, but both having the same cause. Airglow is caused by sunlight splitting atmospheric molecules, which at this point produce during day the dayglow called airglow, which is too faint to be seen in daylight. During the night airglow occurs as nightglow, resulting from the recombination of the molecules which were split during daytime. History The airglow phenomenon was first identified in 1868 by Swedish physicist Anders Ångström. Since then, it has been studied in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
México City At Night 2005
Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundaries with the Pacific Ocean to the west, the Caribbean Sea to the southeast, and the Gulf of Mexico to the east. Mexico covers 1,972,550 km2 (761,610 sq mi), and is the thirteenth-largest country in the world by land area. With a population exceeding 130 million, Mexico is the tenth-most populous country in the world and is home to the largest number of native Spanish speakers. Mexico City is the capital and largest city, which ranks among the most populous metropolitan areas in the world. Human presence in Mexico dates back to at least 8,000 BC. Mesoamerica, considered a cradle of civilization, was home to numerous advanced societies, including the Olmecs, Maya, Zapotecs, Teotihuacan civilization, and Purépecha. Spanish coloni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rayleigh Scattering
Rayleigh scattering ( ) is the scattering or deflection of light, or other electromagnetic radiation, by particles with a size much smaller than the wavelength of the radiation. For light frequencies well below the resonance frequency of the scattering medium (normal dispersion relation, dispersion regime), the amount of scattering is inversely proportional to the fourth power of the wavelength (e.g., a blue color is scattered much more than a red color as light propagates through air). The phenomenon is named after the 19th-century British physicist Lord Rayleigh (John William Strutt). Rayleigh scattering results from the electric polarizability of the particles. The oscillating electric field of a light wave acts on the charges within a particle, causing them to move at the same frequency. The particle, therefore, becomes a small radiating dipole whose radiation we see as scattered light. The particles may be individual atoms or molecules; it can occur when light travels throu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Developed Country
A developed country, or advanced country, is a sovereign state that has a high quality of life, developed economy, and advanced technological infrastructure relative to other less industrialized nations. Most commonly, the criteria for evaluating the degree of economic development are the gross domestic product (GDP), gross national product (GNP), the per capita income, level of industrialization, amount of widespread infrastructure and general standard of living. Which criteria are to be used and which countries can be classified as being developed are subjects of debate. Different definitions of developed countries are provided by the International Monetary Fund and the World Bank; moreover, HDI ranking is used to reflect the composite index of life expectancy, education, and income per capita. In 2025, 40 countries fit all three criteria, while an additional 21 countries fit two out of three. Developed countries have generally more advanced post-industrial economies, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Suburban Night Sky
A suburb (more broadly suburban area) is an area within a metropolitan area. They are oftentimes where most of a metropolitan areas jobs are located with some being predominantly residential. They can either be denser or less densely populated than the city and can have a higher or lower rate of detached single family homes than the city as well. Suburbs can have their own political or legal jurisdictions, especially in the United States, but this is not always the case, especially in the United Kingdom, where most suburbs are located within the administrative boundaries of cities. In most English-speaking countries, suburban areas are defined in contrast to central city or inner city areas, but in Australian English and South African English, ''suburb'' has become largely synonymous with what is called a "neighborhood" in the U.S. Due in part to historical trends such as white flight, some suburbs in the United States have a higher population and higher incomes than their near ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clouds
In meteorology, a cloud is an aerosol consisting of a visible mass of miniature liquid droplets, frozen crystals, or other particles, suspended in the atmosphere of a planetary body or similar space. Water or various other chemicals may compose the droplets and crystals. On Earth, clouds are formed as a result of saturation of the air when it is cooled to its dew point, or when it gains sufficient moisture (usually in the form of water vapor) from an adjacent source to raise the dew point to the ambient temperature. Clouds are seen in the Earth's homosphere, which includes the troposphere, stratosphere, and mesosphere. Nephology is the science of clouds, which is undertaken in the cloud physics branch of meteorology. The World Meteorological Organization uses two methods of naming clouds in their respective layers of the homosphere, Latin and common name. Genus types in the troposphere, the atmospheric layer closest to Earth's surface, have Latin names because of the u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Effect Of Light Pollution On Clouds
Effect may refer to: * A result or change of something ** List of effects ** Cause and effect, an idiom describing causality Pharmacy and pharmacology * Drug effect, a change resulting from the administration of a drug ** Therapeutic effect, a beneficial change in medical condition, often caused by a drug ** Adverse effect or side effect, an unwanted change in medical condition caused by a drug In media * Special effect, an artificial illusion ** Sound effect, an artificially created or enhanced sound ** Visual effects, artificially created or enhanced images *Audio signal processing ** Effects unit, a device used to manipulate electronic sound *** Effects pedal, a small device attached to an instrument to modify its sound Other uses * Effects, one's personal property or belongings * Effects (G.I. Joe), a fictional character in the G.I. Joe universe * ''Effects'' (film), a 1979 film (give a wide release in 2005) * Effect size, a measure of the strength of a relationship betw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mie Theory
In electromagnetism, the Mie solution to Maxwell's equations (also known as the Lorenz–Mie solution, the Lorenz–Mie–Debye solution or Mie scattering) describes the scattering of an electromagnetic plane wave by a homogeneous sphere. The solution takes the form of an infinite series of Vector spherical harmonics, spherical multipole partial waves. It is named after German physicist Gustav Mie. The term ''Mie solution'' is also used for solutions of Maxwell's equations for scattering by stratified spheres or by infinite cylinders, or other geometries where one can write separation of variables, separate equations for the radial and angular dependence of solutions. The term ''Mie theory'' is sometimes used for this collection of solutions and methods; it does not refer to an independent physical theory or law. More broadly, the "Mie scattering" formulas are most useful in situations where the size of the scattering particles is comparable to the wavelength of the light, rather ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aerosols
An aerosol is a suspension of fine solid particles or liquid droplets in air or another gas. Aerosols can be generated from natural or human causes. The term ''aerosol'' commonly refers to the mixture of particulates in air, and not to the particulate matter alone. Examples of natural aerosols are fog, mist or dust. Examples of human caused aerosols include particulate air pollutants, mist from the discharge at hydroelectric dams, irrigation mist, perfume from atomizers, smoke, dust, sprayed pesticides, and medical treatments for respiratory illnesses. Several types of atmospheric aerosol have a significant effect on Earth's climate: volcanic, desert dust, sea-salt, that originating from biogenic sources and human-made. Volcanic aerosol forms in the stratosphere after an eruption as droplets of sulfuric acid that can prevail for up to two years, and reflect sunlight, lowering temperature. Desert dust, mineral particles blown to high altitudes, absorb heat and may ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Backscatter
In physics, backscatter (or backscattering) is the reflection of waves, particles, or signals back to the direction from which they came. It is usually a diffuse reflection due to scattering, as opposed to specular reflection as from a mirror, although specular backscattering can occur at normal incidence with a surface. Backscattering has important applications in astronomy, photography, and medical ultrasonography. The opposite effect is forward scatter, e.g. when a translucent material like a cloud diffuses sunlight, giving soft light. Backscatter of waves in physical space Backscattering can occur in quite different physical situations, where the incoming waves or particles are deflected from their original direction by different mechanisms: *Diffuse reflection from large particles and Mie scattering, causing alpenglow and gegenschein, and showing up in weather radar; *Inelastic collisions between electromagnetic waves and the transmitting medium ( Brillouin scattering ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
