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Umbra
The umbra, penumbra and antumbra are three distinct parts of a shadow, created by any light source after impinging on an opaque object of lesser size. In cases of equal or smaller impinging objects, only an umbra and penumba are generated. Assuming no diffraction, for a collimated beam (such as a point source) of light, only the umbra is cast. These phenomena are generally observed within solar systems, as the size of the stars within the system are larger than the orbiting satellites, hence these terms are most often used for the shadows cast by celestial bodies, though they are sometimes used to describe levels of darkness, such as in sunspots. Umbra The umbra () is the innermost and darkest part of a shadow, where the light source is completely blocked by the occluding body. An observer within the umbra experiences a total occultation. The umbra of a round body occluding a round light source forms a right circular cone. When viewed from the cone's apex, the two bodies ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antumbra
The umbra, penumbra and antumbra are three distinct parts of a shadow, created by any light source after impinging on an Opacity (optics), opaque object of lesser size. In cases of equal or smaller impinging objects, only an umbra and penumba are generated. Assuming no diffraction, for a collimated beam (such as a point source) of light, only the umbra is cast. These phenomena are generally observed within solar systems, as the size of the stars within the system are larger than the orbiting satellites, hence these terms are most often used for the shadows cast by celestial body, celestial bodies, though they are sometimes used to describe levels of darkness, such as in sunspots. Umbra The umbra () is the innermost and darkest part of a shadow, where the light source is completely blocked by the occluding body. An observer within the umbra experiences a total occultation. The umbra of a round body occluding a round light source forms a cone, right circular cone. When viewed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Partial Eclipse
An eclipse is an astronomical event which occurs when an astronomical object or spacecraft is temporarily obscured, by passing into the shadow of another body or by having another body pass between it and the viewer. This alignment of three celestial objects is known as a ''syzygy''. An eclipse is the result of either an ''occultation'' (completely hidden) or a ''transit'' (partially hidden). A "deep eclipse" (or "deep occultation") is when a small astronomical object is behind a bigger one. "What is a deep eclipse? The smaller star is behind the bigger star" The term ''eclipse'' is most often used to describe either a solar eclipse, when the Moon's shadow crosses the Earth's surface, or a lunar eclipse, when the Moon moves into the Earth's shadow. However, it can also refer to such events beyond the Earth–Moon system: for example, a planet moving into the shadow cast by one of its moons, a moon passing into the shadow cast by its host planet, or a moon passing into the sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Annular Eclipse
A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby obscuring the view of the Sun from a small part of Earth, totally or partially. Such an alignment occurs approximately every six months, during the eclipse season in its new moon phase, when the Moon's orbital plane is closest to the plane of Earth's orbit. In a total eclipse, the disk of the Sun is fully obscured by the Moon. In partial and annular eclipses, only part of the Sun is obscured. Unlike a lunar eclipse, which may be viewed from anywhere on the night side of Earth, a solar eclipse can only be viewed from a relatively small area of the world. As such, although total solar eclipses occur somewhere on Earth every 18 months on average, they recur at any given place only once every 360 to 410 years. If the Moon were in a perfectly circular orbit and in the same orbital plane as Earth, there would be total solar eclipses once a month, at every new moon. Instead, because the Moon's orbit is t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sunspots
Sunspots are temporary spots on the Sun's surface that are darker than the surrounding area. They are one of the most recognizable Solar phenomena and despite the fact that they are mostly visible in the solar photosphere they usually affect the entire solar atmosphere. They are regions of reduced surface temperature caused by concentrations of magnetic flux that inhibit convection. Sunspots appear within active regions, usually in pairs of opposite magnetic polarity. Their number varies according to the approximately 11-year solar cycle. Individual sunspots or groups of sunspots may last anywhere from a few days to a few months, but eventually decay. Sunspots expand and contract as they move across the surface of the Sun, with diameters ranging from to . Larger sunspots can be visible from Earth without the aid of a telescope. They may travel at relative speeds, or proper motions, of a few hundred meters per second when they first emerge. Indicating intense magnetic a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shadow
A shadow is a dark area on a surface where light from a light source is blocked by an object. In contrast, shade occupies the three-dimensional volume behind an object with light in front of it. The cross-section of a shadow is a two-dimensional silhouette, or a reverse projection of the object blocking the light. Point and non-point light sources A point source of light casts only a simple shadow, called an "umbra". For a non-point or "extended" source of light, the shadow is divided into the umbra, penumbra, and antumbra. The wider the light source, the more blurred the shadow becomes. If two penumbras overlap, the shadows appear to attract and merge. This is known as the shadow blister effect. The outlines of the shadow zones can be found by tracing the rays of light emitted by the outermost regions of the extended light source. The umbra region does not receive any direct light from any part of the light source and is the darkest. A viewer located in the umbra regi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth's Shadow
Earth's shadow (or Earth shadow) is the shadow that Earth itself casts through its atmosphere and into outer space, toward the antisolar point. During the twilight period (both early dusk and late dawn), the shadow's visible fringe – sometimes called the dark segment or twilight wedge – appears as a dark and diffuse band just above the horizon, most distinct when the sky is clear. Since the angular diameters of the Sun and the Moon as viewed from Earth's surface are almost the same, the ratio of the length of Earth's shadow to the distance between Earth and the Moon will be almost equal to the ratio of the diameters of Earth and the Moon. Since Earth's diameter is 3.7 times the Moon's, the length of the planet's umbra is correspondingly 3.7 times the average distance from the Moon to Earth: about . The diameter of Earth's shadow at lunar distance is about , or 2.6 lunar diameters, which allows observation of total lunar eclipses from Earth. Appearance Earth's shadow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lunar Distance (astronomy)
The instantaneous Earth–Moon distance, or distance to the Moon, is the distance from the center of Earth to the center of the Moon. In contrast, the Lunar distance (LD or \Delta_), or Earth–Moon characteristic distance, is a unit of measure in astronomy. More technically, it is the semi-major axis of the geocentric orbit of the Moon, lunar orbit. The average lunar distance is approximately , or 1.3 light-seconds. It is roughly 30 times Earth radius, Earth's diameter and a non-stop plane flight traveling that distance would take more than two weeks. Around 389 lunar distances make up an astronomical unit (roughly the distance from Earth to the Sun). Lunar distance is commonly used to express the distance to near-Earth object encounters. Lunar semi-major axis is an important astronomical datum. It has implications for testing gravitational theories such as general relativity and for refining other astronomical values, such as the Earth mass, mass, Earth radius, radius, and Ea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antisolar Point
The antisolar point is the abstract point on the celestial sphere directly opposite the Sun from an observer's perspective. This means that the antisolar point lies above the horizon when the Sun is below it, and vice versa. On a sunny day, the antisolar point can be easily found; it is located within the shadow of the observer's head. Like the zenith and nadir, the antisolar point is not fixed in three-dimensional space, but is defined relative to the observer. Each observer has an antisolar point that moves as the observer changes position. The antisolar point forms the geometric center of several optical phenomena, including subhorizon haloes, rainbows, glories, the Brocken spectre, and heiligenschein. Occasionally, around sunset or sunrise, anticrepuscular rays appear to converge toward the antisolar point near the horizon. However, this is an optical illusion caused by perspective; in reality, the "rays" (i.e. bands of shadow) run near-parallel to each other. Also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diagram Of Umbra, Penumbra & Antumbra
A diagram is a symbolic Depiction, representation of information using Visualization (graphics), visualization techniques. Diagrams have been used since prehistoric times on Cave painting, walls of caves, but became more prevalent during the Age of Enlightenment, Enlightenment. Sometimes, the technique uses a Three-dimensional space, three-dimensional visualization which is then graphical projection, projected onto a two-dimensional surface. The word ''graphics, graph'' is sometimes used as a synonym for diagram. Overview The term "diagram" in its commonly used sense can have a general or specific meaning: * ''visual information device'' : Like the term "illustration", "diagram" is used as a collective term standing for the whole class of technical genres, including graphics, graphs, technical drawings and tables. * ''specific kind of visual display'' : This is the genre that shows qualitative data with shapes that are connected by lines, arrows, or other visual links. In scie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ohio State University
The Ohio State University (Ohio State or OSU) is a public university, public Land-grant university, land-grant research university in Columbus, Ohio, United States. A member of the University System of Ohio, it was founded in 1870. It is one of the List of largest United States university campuses by enrollment, largest universities by enrollment in the United States, with nearly 50,000 undergraduate students and nearly 15,000 graduate students. The university consists of sixteen colleges and offers over 400 degree programs at the undergraduate and Graduate school, graduate levels. It is Carnegie Classification of Institutions of Higher Education, classified among "R1: Doctoral Universities – Very high research activity". the university has an List of colleges and universities in the United States by endowment, endowment of $7.9 billion. Its athletic teams compete in NCAA Division I as the Ohio State Buckeyes as a member of the Big Ten Conference for the majority of fielde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transit Of Mercury, May 9th, 2016
Transit may refer to: Arts and entertainment Film * ''Transit'' (1980 film), a 1980 Israeli film * ''Transit'' (1986 film), a Canadian short film * ''Transit'' (2005 film), a film produced by MTV and Staying-Alive about four people in countries in the world * ''Transit'' (2006 film), a 2006 film about Russian and American pilots in World War II * ''Transit'' (2012 film), an American thriller * ''Transit'' (2013 film), a Filipino independent film * ''Transit'' (2018 film), a German film Literature * ''Transit'' (Cooper novel), a 1964 science fiction by Edmund Cooper * ''Transit'' (Seghers novel), a 1944 novel by Anna Seghers * ''Transit'' (Aaronovitch novel), a 1992 novel by Ben Aaronovitch based on the TV series ''Doctor Who'' Music * Transit (band), an American emo band from Boston, Massachusetts * ''Transit'' (Ira Stein and Russel Walder album), an album by acoustic duo Ira Stein and Russel Walder, released 1986 * ''Transit'' (Sponge Cola album) * ''Tra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Partial Lunar Eclipse 2019-07-16
Partial may refer to: Mathematics *Partial derivative, derivative with respect to one of several variables of a function, with the other variables held constant ** ∂, a symbol that can denote a partial derivative, sometimes pronounced "partial dee" **Partial differential equation, a differential equation that contains unknown multivariable functions and their partial derivatives Other uses *Partial application, in computer science the process of fixing a number of arguments to a function, producing another function *Partial charge or net atomic charge, in chemistry a charge value that is not an integer or whole number *Partial fingerprint, impression of human fingers used in criminology or forensic science *Partial seizure or focal seizure, a seizure that initially affects only one hemisphere of the brain * Partial or Part score, in contract bridge a trick score less than 100, as well as other meanings * Partial or Partial wave, one sound wave of which a complex tone is composed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
