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Blue Jets
Upper-atmospheric lightning and ionospheric lightning are terms sometimes used by researchers to refer to a family of short-lived electrical-breakdown phenomena that occur well above the altitudes of normal lightning and storm clouds. Upper-atmospheric lightning is believed to be electrically induced forms of luminous plasma. The preferred usage is transient luminous event (TLE), because the various types of electrical-discharge phenomena in the upper atmosphere lack several characteristics of the more familiar tropospheric lightning. Transient luminous events have also been observed in far-ultraviolet images of Jupiter's upper atmosphere, high above the altitude of lightning-producing water clouds. Characteristics There are several types of TLEs, the most common being sprites. Sprites are flashes of bright red light that occur above storm systems. C-sprites (short for "columniform sprites") is the name given to vertical columns of red light. C-sprites exhibiting tendrils ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lightning Sprites
Sprites or red sprites are large-scale electric discharges that occur in the mesosphere, high above thunderstorm clouds, or cumulonimbus, giving rise to a varied range of visual shapes flickering in the night sky. They are usually triggered by the discharges of positive lightning between an underlying thundercloud and the ground. Precis Sprites appear as luminous red-orange flashes. They often occur in clusters above the troposphere at an altitude range of . Sporadic visual reports of sprites go back at least to 1886. They were first photographed on July 4, 1989, by John R. Winckler, scientists from the University of Minnesota and have subsequently been captured in video recordings thousands of times. Sprites are sometimes inaccurately called upper-atmospheric lightning. However, they are cold plasma (physics), plasma phenomena that lack the hot channel temperatures of Troposphere, tropospheric lightning, so they are more akin to fluorescent tube discharges than to lightnin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Recording
The history of optical recording can be divided into a few number of distinct major contributions. The pioneers of optical recording worked mostly independently, and their solutions to the many technical challenges have very distinctive features, such as *reflective disc (Compaan and Kramer) *transparent disc (Gregg) *floppy disc (Russell) *rigid disc (Compaan and Kramer) *focused laser beam for read-out through transparent substrate (Compaan and Kramer). Gregg 1958 Laserdisc technology, using a transparent disc, was invented by David Paul Gregg in 1958 (and patented in 1970 and 1990). By 1969 Philips had developed a videodisc in reflective mode, which has great advantages over the transparent mode. MCA and Philips decided to join their efforts. They first publicly demonstrated the videodisc in 1972. Laserdisc was first available on the market, in Atlanta, on December 15, 1978, two years after the VHS VCR and four years before the CD, which is based on Laserdisc technology. Phi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth
Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all of Earth's water is contained in its global ocean, covering Water distribution on Earth, 70.8% of Earth's crust. The remaining 29.2% of Earth's crust is land, most of which is located in the form of continental landmasses within Earth's land hemisphere. Most of Earth's land is at least somewhat humid and covered by vegetation, while large Ice sheet, sheets of ice at Polar regions of Earth, Earth's polar polar desert, deserts retain more water than Earth's groundwater, lakes, rivers, and Water vapor#In Earth's atmosphere, atmospheric water combined. Earth's crust consists of slowly moving tectonic plates, which interact to produce mountain ranges, volcanoes, and earthquakes. Earth's outer core, Earth has a liquid outer core that generates a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Backronym
A backronym is an acronym formed from an already existing word by expanding its letters into the words of a phrase. Backronyms may be invented with either serious or humorous intent, or they may be a type of false etymology or folk etymology. The word is a portmanteau of ''back'' and ''acronym''. A normal acronym is a word derived from the initial letter(s) of the words of a phrase, such as ''radar'' from "radio detection and ranging". By contrast, a backronym is "an acronym deliberately formed from a phrase whose initial letters spell out a particular word or words, either to create a memorable name or as a fanciful explanation of a word's origin". Many list of fictional espionage organizations, fictional espionage organizations are backronyms, such as SPECTRE (special executive for counterintelligence, terrorism, revenge and extortion) from the ''James Bond'' franchise. For example, the Amber Alert missing-child program was named after Amber Hagerman, a nine-year-old girl w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Puck (A Midsummer Night's Dream)
Puck, or Robin Goodfellow, is a character in William Shakespeare's play, ''A Midsummer Night's Dream''. Based on the Puck of English mythology and the púca of Celtic mythology, Puck is a mischievous fairy, sprite, or jester. He is the first of the main fairy characters to appear, and he significantly influences events in the play. He delights in pranks such as replacing Nick Bottom's head with that of an ass. Appearances in the play The audience is introduced to Puck in 2.1: FAIRY: Either I mistake your shape and making quite, Or else you are that shrewd and knavish sprite Call'd Robin Goodfellow: are you not he That frights the maidens of the villagery; Skim milk, and sometimes labour in the quern, And bootless make the breathless housewife churn; And sometime make the drink to bear no barm; Mislead night wanderers, laughing at their harm? Those that Hobgoblin call you and sweet Puck, You do their work, and they shall have good luck: Are you not he? PUCK: F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ariel (The Tempest)
Ariel is a spirit who appears in William Shakespeare's play ''The Tempest''. Ariel is bound to serve the magician Prospero, who rescued him from the tree in which he was imprisoned by Sycorax, the witch who previously inhabited the island. Prospero greets disobedience with a reminder that he saved Ariel from Sycorax's spells, and with promises to grant Ariel his freedom. Ariel is Prospero's eyes and ears throughout the play, using his magical abilities to cause the tempest in Act One which gives the play its name, and to foil other characters' plots to bring down their master. Ariel means "Lion of God" in the Hebrew language. Ariel may also be a simple play on the word "aerial". Scholars have compared Ariel to spirits depicted in other Elizabethan plays, and have managed to find several similarities between them, but one thing which makes Ariel unique is the human edge and personality given to Ariel by Shakespeare. Because the stage directions in ''The Tempest'' are so preci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sprite (creature)
A sprite is a supernatural entity in European mythology. They are often depicted as fairy-like creatures or as an ethereal entity. Etymology The word ''sprite'' is derived from the Latin ''spiritus'' ("spirit"), via the French '' esprit''. Variations on the term include ''spright'' and the Celtic '' spriggan''. The term is chiefly used with regard to elves and fairies in European folklore, and in modern English is rarely used in reference to spirits. Belief in sprites The belief in diminutive beings such as sprites, elves, fairies, etc. has been common in many parts of the world, and might to some extent still be found within neo-spiritual and religious movements such as " neo-druidism" and Ásatrú. In some elemental magics, the sprite is often believed to be the elemental of air (see also sylph). Water sprite A water sprite (also called a water fairy or water faery) is a general term for an elemental spirit associated with water, according to alchemist Paracelsus. W ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lightning
Lightning is a natural phenomenon consisting of electrostatic discharges occurring through the atmosphere between two electrically charged regions. One or both regions are within the atmosphere, with the second region sometimes occurring on the land, ground. Following the lightning, the regions become partially or wholly electrically neutralized. Lightning involves a near-instantaneous release of energy on a scale averaging between 200 megajoules and 7 gigajoules. The air around the lightning flash rapidly heats to temperatures of about . There is an emission of electromagnetic radiation across a wide range of wavelengths, some visible as a bright flash. Lightning also causes thunder, a sound from the shock wave which develops as heated gases in the vicinity of the discharge experience a sudden increase in pressure. The most common occurrence of a lightning event is known as a thunderstorm, though they can also commonly occur in other types of energetic weather systems, such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cumulonimbus
Cumulonimbus () is a dense, towering, vertical cloud, typically forming from water vapor condensing in the lower troposphere that builds upward carried by powerful buoyant air currents. Above the lower portions of the cumulonimbus the water vapor becomes ice crystals, such as snow and graupel, the interaction of which can lead to hail and to lightning formation, respectively. When causing thunderstorms, these clouds may be called thunderheads. Cumulonimbus can form alone, in clusters, or along squall lines. These clouds are capable of producing lightning and other dangerous severe weather, such as tornadoes, hazardous winds, and large hailstones. Cumulonimbus progress from overdeveloped cumulus congestus clouds and may further develop as part of a supercell. Cumulonimbus is abbreviated as Cb. Description Towering cumulonimbus clouds are typically accompanied by smaller cumulus clouds. The cumulonimbus base may extend several kilometres (miles) across, or be as small as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Discharge
In electromagnetism, an electric discharge is the release and transmission of electricity in an applied electric field through a medium such as a gas (i.e., an outgoing flow of electric current through a non-metal medium).American Geophysical Union, National Research Council (U.S.). Geophysics Study Committee (1986) ''The earth's electrical environment''. National Academy Press, Washington, DC, p. 263. Applications The properties and effects of electric discharges are useful over a wide range of magnitudes. Tiny pulses of current are used to detect ionizing radiation in a Geiger–Müller tube. A low steady current can illustrate the gas spectrum in a gas-filled tube. A neon lamp is an example of a gas-discharge lamp, useful both for illumination and as a voltage regulator. A flashtube generates a short pulse of intense light useful for photography by sending a heavy current through a gas arc discharge. Corona discharges are used in photocopiers. Electric discharges can convey ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
