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Corona (meteorology)
In meteorology, a corona (plural ''coronae'') is an optical phenomenon produced by the diffraction of sunlight or moonlight (or, occasionally, bright starlight or planetlight) by individual small water droplets and sometimes tiny ice crystals of a cloud or on a foggy glass surface. In its full form, a corona consists of several concentric, pastel-colored rings around the celestial object and a central bright area called ''aureole''. The aureole is often (especially in case of the Moon) the only visible part of the corona and has the appearance of a bluish-white disk which fades to reddish-brown towards the edge. The angular diameter of a corona depends on the sizes of the water droplets involved; smaller droplets produce larger coronae. For the same reason, the corona is the most pronounced when the size of the droplets is most uniform. Coronae differ from halos in that the latter are formed by refraction (rather than diffraction) from comparatively large rather than small ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lunar Halo
Lunar most commonly means "of or relating to the Moon". Lunar may also refer to: Arts and entertainment * Lunar (series), ''Lunar'' (series), a series of video games * Lunar (song), "Lunar" (song), by David Guetta * "Lunar", a song by Priestess from the 2009 album ''Prior to the Fire'' * Lunars, a fictional race in the series ''The Lunar Chronicles'' by Marissa Meyer Other uses * Lunar Magic, Super Mario World level editor * Lunar Design, or LUNAR, a San Francisco-based design consultancy * Hasselblad Lunar, a digital camera * Lunar, a brandname of Ethinylestradiol/cyproterone acetate, a birth control pill * Lunar C (Jake Brook, born 1990), English rapper See also * * * Lunar calendar, based upon the monthly cycles of the Moon's phase ** Lunar day, in such calendars ** Lunar month, in such calendars * Moon (other) * Luna (other) {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moon
The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of Australia). The Moon is a planetary-mass object with a differentiated rocky body, making it a satellite planet under the geophysical definitions of the term and larger than all known dwarf planets of the Solar System. It lacks any significant atmosphere, hydrosphere, or magnetic field. Its surface gravity is about one-sixth of Earth's at , with Jupiter's moon Io being the only satellite in the Solar System known to have a higher surface gravity and density. The Moon orbits Earth at an average distance of , or about 30 times Earth's diameter. Its gravitational influence is the main driver of Earth's tides and very slowly lengthens Earth's day. The Moon's orbit around Earth has a sidereal period of 27.3 days. During each synodic period ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mumbai
Mumbai (, ; also known as Bombay — the official name until 1995) is the capital city of the Indian state of Maharashtra and the ''de facto'' financial centre of India. According to the United Nations, as of 2018, Mumbai is the second-most populous city in India after Delhi and the eighth-most populous city in the world with a population of roughly 20 million (2 crore). As per the Indian government population census of 2011, Mumbai was the most populous city in India with an estimated city proper population of 12.5 million (1.25 crore) living under the Brihanmumbai Municipal Corporation. Mumbai is the centre of the Mumbai Metropolitan Region, the sixth most populous metropolitan area in the world with a population of over 23 million (2.3 crore). Mumbai lies on the Konkan coast on the west coast of India and has a deep natural harbour. In 2008, Mumbai was named an alpha world city. It has the highest number of millionaires and billionaires among all cities i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Cloud Types
The list of cloud types groups all genera as ''high'' (cirro-, cirrus), ''middle'' (alto-), ''multi-level'' (nimbo-, cumulo-, cumulus), and ''low'' (strato-, stratus). These groupings are determined by the altitude level or levels in the troposphere at which each of the various cloud types is normally found. Small cumulus are commonly grouped with the low clouds because they do not show significant vertical extent. Of the multi-level genus-types, those with the greatest convective activity are often grouped separately as ''towering vertical''. The genus types all have Latin names. The genera are also grouped into five physical forms. These are, in approximate ascending order of instability or convective activity: ''stratiform'' sheets; ''cirriform'' wisps and patches; ''stratocumuliform'' patches, rolls, and ripples; ''cumuliform'' heaps, and ''cumulonimbiform'' towers that often have complex structures. Most genera are divided into ''species'' with Latin names, some of which are c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Golden Gate Bridge
The Golden Gate Bridge is a suspension bridge spanning the Golden Gate, the strait connecting San Francisco Bay and the Pacific Ocean. The structure links the U.S. city of San Francisco, California—the northern tip of the San Francisco Peninsula—to Marin County, carrying both U.S. Route 101 and California State Route 1 across the strait. It also carries pedestrian and bicycle traffic, and is designated as part of U.S. Bicycle Route 95. Being declared one of the Wonders of the Modern World by the American Society of Civil Engineers, the bridge is one of the most internationally recognized symbols of San Francisco and California. It was initially designed by engineer Joseph Strauss in 1917. The bridge was named for the Golden Gate strait, the channel that it spans. The Frommer's travel guide describes the Golden Gate Bridge as "possibly the most beautiful, certainly the most photographed, bridge in the world." At the time of its opening in 1937, it was both the longe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
22° Halo
A 22° halo is an atmospheric optical phenomenon that consists of a halo with an apparent radius of approximately 22° around the Sun or Moon. When visible around the Moon, it is also known as a moon ring or winter halo. It forms as sunlight or moonlight is refracted by millions of hexagonal ice crystals suspended in the atmosphere. Its radius is roughly the length of an outstretched hand at arm's length. Formation Even though it is one of the most common types of halo, the exact shape and orientation of the ice crystals responsible for the 22° halo are the topic of debate. Hexagonal, randomly oriented columns are usually put forward as the most likely candidate, but this explanation presents problems, such as the fact that the aerodynamic properties of such crystals leads them to be oriented horizontally rather than randomly. Alternative explanations include the involvement of clusters of bullet-shaped ice columns. As light passes through the 60° apex angle of the hexa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glory (optical Phenomenon)
A glory is an optical phenomenon, resembling an iconic saint's halo around the shadow of the observer's head, caused by sunlight or (more rarely) moonlight interacting with the tiny water droplets that comprise mist or clouds. The glory consists of one or more concentric, successively dimmer rings, each of which is red on the outside and bluish towards the centre. Due to its appearance, the phenomenon is sometimes mistaken for a circular rainbow, but the latter has a much larger diameter and is caused by different physical processes. Glories arise due to wave interference of light internally refracted within small droplets. Appearance and observation Depending on circumstances (such as the uniformity of droplet size in the clouds), one or more of the glory's rings can be visible. The angular size of the inner and brightest ring is much smaller than that of a rainbow, about 5° to 20°, depending on the size of the droplets. In the right conditions, a glory and a rainbow can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmospheric Diffraction
Atmospheric diffraction is manifested in the following principal ways: * Optical atmospheric diffraction * Radio wave diffraction is the scattering of radio frequency or lower frequencies from the Earth's ionosphere, resulting in the ability to achieve greater distance radio broadcasting. * Sound wave diffraction is the bending of sound waves, as the sound travels around edges of geometric objects. This produces the effect of being able to hear even when the source is blocked by a solid object. The sound waves bend appreciably around the solid object. However, if the object has a diameter greater than the acoustics, acoustic wavelength, a 'sound shadow' is cast behind the object where the sound is inaudible. (Note: some sound may be propagated through the object depending on material). Optical atmospheric diffraction When light travels through thin clouds made up of nearly uniform sized water or aerosol droplets or ice crystals, diffraction or bending of light occurs as the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pollen
Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametophytes during the process of their movement from the stamens to the pistil of flowering plants, or from the male cone to the female cone of gymnosperms. If pollen lands on a compatible pistil or female cone, it germinates, producing a pollen tube that transfers the sperm to the ovule containing the female gametophyte. Individual pollen grains are small enough to require magnification to see detail. The study of pollen is called palynology and is highly useful in paleoecology, paleontology, archaeology, and forensics. Pollen in plants is used for transferring haploid male genetic material from the anther of a single flower to the stigma of another in cross-pollination. In a case of self-pollination, this process takes place from the anth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Airy Disk
In optics, the Airy disk (or Airy disc) and Airy pattern are descriptions of the best- focused spot of light that a perfect lens with a circular aperture can make, limited by the diffraction of light. The Airy disk is of importance in physics, optics, and astronomy. The diffraction pattern resulting from a uniformly illuminated, circular aperture has a bright central region, known as the Airy disk, which together with the series of concentric rings around is called the Airy pattern. Both are named after George Biddell Airy. The disk and rings phenomenon had been known prior to Airy; John Herschel described the appearance of a bright star seen through a telescope under high magnification for an 1828 article on light for the ''Encyclopedia Metropolitana'': Airy wrote the first full theoretical treatment explaining the phenomenon (his 1835 "On the Diffraction of an Object-glass with Circular Aperture"). Mathematically, the diffraction pattern is characterized by the wavelen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Refraction
In physics, refraction is the redirection of a wave as it passes from one medium to another. The redirection can be caused by the wave's change in speed or by a change in the medium. Refraction of light is the most commonly observed phenomenon, but other waves such as sound waves and water waves also experience refraction. How much a wave is refracted is determined by the change in wave speed and the initial direction of wave propagation relative to the direction of change in speed. For light, refraction follows Snell's law, which states that, for a given pair of media, the ratio of the sines of the angle of incidence ''θ1'' and angle of refraction ''θ2'' is equal to the ratio of phase velocities (''v''1 / ''v''2) in the two media, or equivalently, to the refractive indices (''n''2 / ''n''1) of the two media. :\frac =\frac=\frac Optical prisms and lenses use refraction to redirect light, as does the human eye. The refractive index of materials varies with the wavelengt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halo (optical Phenomenon)
A halo is an optical phenomenon produced by light (typically from the Sun or Moon) interacting with ice crystals suspended in the atmosphere. Halos can have many forms, ranging from colored or white rings to arcs and spots in the sky. Many of these appear near the Sun or Moon, but others occur elsewhere or even in the opposite part of the sky. Among the best known halo types are the circular halo (properly called the 22° halo), light pillars, and sun dogs, but many others occur; some are fairly common while others are extremely rare. The ice crystals responsible for halos are typically suspended in cirrus or cirrostratus clouds in the upper troposphere (), but in cold weather they can also float near the ground, in which case they are referred to as diamond dust. The particular shape and orientation of the crystals are responsible for the type of halo observed. Light is reflected and refracted by the ice crystals and may split into colors because of dispersion. The crystals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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