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Gegenschein
Gegenschein (; ; ) or counterglow is a faintly bright spot in the night sky centered at the antisolar point. The backscatter of sunlight by interplanetary dust causes this optical phenomenon, being a zodiacal light and part of its zodiacal light band. Explanation Like zodiacal light, gegenschein is sunlight light scattering by particles, scattered by interplanetary dust cloud, interplanetary dust. Most of this dust orbits the Sun near the ecliptic plane, with a possible concentration of particles centered at the point of the Earth–Sun system. Gegenschein is distinguished from zodiacal light by its high angle of incidence (optics), angle of reflection of the incident sunlight on the dust particles. It forms a slightly brighter elliptical spot of 8–10° across opposition (astronomy), directly opposite the Sun within the dimmer band of zodiacal light and zodiac constellation. The intensity of the gegenschein is opposition surge, relatively enhanced because each dust par ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zodiacal Light
The zodiacal light (also called false dawn when seen before sunrise) is a faint glow of diffuse sunlight scattered by interplanetary dust. Brighter around the Sun, it appears in a particularly dark night sky to extend from the Sun's direction in a roughly triangular shape along the zodiac, and appears with less intensity and visibility along the whole ecliptic as the zodiacal band. Zodiacal light spans the entire sky and contributes to the natural light of a clear and moonless night sky. A related phenomenon is ''gegenschein'' (or ''counterglow''), sunlight backscattered from the interplanetary dust, which appears directly opposite to the Sun as a faint but slightly brighter oval glow. Zodiacal light contributes to the natural light of the sky, though since zodiacal light is very faint, it is often outshone and rendered invisible by moonlight or light pollution. The interplanetary dust in the Solar System forms a thick, pancake-shaped cloud called the zodiacal cloud wh ... [...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] |
Edward Emerson Barnard
Edward Emerson Barnard (December 16, 1857 – February 6, 1923) was an American astronomer. He was commonly known as E. E. Barnard, and was recognized as a gifted observational astronomer. He is best known for his discovery of the high proper motion of Barnard's Star in 1916, which is named in his honor. Early life Barnard was born in Nashville, Tennessee, on December 16, 1857, to Reuben Barnard and Elizabeth Jane Barnard (''née'' Haywood), and had one brother. His father died three months before his birth, so he grew up in an impoverished family and did not receive much in the way of formal education. His first interest was in the field of photography, and he became a photographer's assistant at the age of nine. He later developed an interest in astronomy. In 1876 he purchased a refractor telescope, and in 1881 he discovered his first comet, but failed to announce his discovery. He found his second comet later the same year and a third in 1882. While he was still working a ... [...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] |
Interplanetary Dust
The interplanetary dust cloud, or zodiacal cloud (as the source of the zodiacal light), consists of cosmic dust (small particles floating in outer space) that pervades the space between planets within planetary systems, such as the Solar System. This system of particles has been studied for many years in order to understand its nature, origin, and relationship to larger bodies. There are several methods to obtain space dust measurement. In the Solar System, interplanetary dust particles have a role in scattering sunlight and in emitting thermal radiation, which is the most prominent feature of the night sky's radiation, with wavelengths ranging 5–50 μm. The particle sizes of grains characterizing the infrared emission near Earth's orbit typically range 10–100 μm. Microscopic impact craters on lunar rocks returned by the Apollo Program revealed the size distribution of cosmic dust particles bombarding the lunar surface. The ’’Grün’’ distribution of interplanetar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Theodor Brorsen
Theodor Johan Christian Ambders Brorsen (29 July 1819 – 31 March 1895) was a Danish astronomer. He is best known for his discovery of five comets, including the lost periodic comet, 5D/Brorsen, and the periodic comet 23P/Brorsen-Metcalf. Life Theodor Johan Christian Ambders Brorsen was born in Nordborg on the island Als, ( South Jutland), as son of the captain Christian August Brorsen (1793-1840) and Annette Margrethe Gerhardine Schumacher (1788-1855). He got his three middle names after the maternal grandfather of his mother, the Nordborg counsel Johan Christian Ambders (1710-1795). After the amicable divorce of his parents in 1822, Brorsen grew up at his mother's. Her good financial circumstances allowed him to attend the school of the Moravians in Christiansfeld (1826-1829) and then, from 1830 to 1839, the Latin school in Flensburg. By request of his mother, Brorsen studied law in Kiel (1839), Berlin (1840), Heidelberg (1841), and again in Kiel (1842), until he ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interplanetary Dust Cloud
The interplanetary dust cloud, or zodiacal cloud (as the source of the zodiacal light), consists of cosmic dust (small particles floating in outer space) that pervades the space between planets within planetary systems, such as the Solar System. This system of particles has been studied for many years in order to understand its nature, origin, and relationship to larger bodies. There are several methods to obtain space dust measurement. In the Solar System, interplanetary dust particles have a role in scattering sunlight and in emitting thermal radiation, which is the most prominent feature of the night sky's radiation, with wavelengths ranging 5–50 μm. The particle sizes of grains characterizing the infrared emission near Earth's orbit typically range 10–100 μm. Microscopic impact craters on lunar rocks returned by the Apollo Program revealed the size distribution of cosmic dust particles bombarding the lunar surface. The ’’Grün’’ distribution of interplan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Texas State University
Texas State University (TXST) is a public university, public research university with its main campus in San Marcos, Texas, United States, and another campus in Round Rock, Texas, Round Rock. Since its establishment in 1899, the university has grown to be one of the largest universities in the United States. Texas State University reached a record enrollment of 40,678 students in the 2024 fall semester, continuing a trend of enrollment growth over several years. Texas State University offers over 200 bachelor's, master's, and doctoral degree programs from its nine colleges. The university is Higher education accreditation in the United States, accredited by the Southern Association of Colleges and Schools (SACS) and designated as a Hispanic-Serving Institution (HSI) by the U.S. Department of Education. Texas State is Carnegie Classification of Institutions of Higher Education, classified among "R2: Doctoral Universities – High research activity" and an Emerging Research Unive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Donald Olson (astronomer)
Donald W. Olson is an astrophysicist and forensic astronomer at the Texas State University. Nicknamed the "Celestial Sleuth," he is known for studying art and history using astronomical data. He is currently regents professor emeritus at Texas State's Department of Physics. Education Olson received a B.S. in physics from Michigan State University. Upon graduating, he was awarded the Thomas H. Osgood Undergraduate Physics Award. He later studied at University of California-Berkeley, where he received his PhD. Olson went on to study at Cornell University and University of Texas at Austin, before taking up a teaching position at Texas State University in 1981. Career Olson began his career studying the theory of relativity and creating computer simulations of astronomical phenomena such as the distribution of galaxies or radiation near black holes. He became well known for his work in the field of forensic astronomy, often in collaboration with fellow astrophysicist Russell D ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CRC Press
The CRC Press, LLC is an American publishing group that specializes in producing technical books. Many of their books relate to engineering, science and mathematics. Their scope also includes books on business, forensics and information technology. CRC Press is now a division of Taylor & Francis, itself a subsidiary of Informa. History The CRC Press was founded as the Chemical Rubber Company (CRC) in 1903 by brothers Arthur, Leo and Emanuel Friedman in Cleveland, Ohio, based on an earlier enterprise by Arthur, who had begun selling rubber laboratory aprons in 1900. The company gradually expanded to include sales of laboratory equipment to chemist A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin ''alchemist'') is a graduated scientist trained in the study of chemistry, or an officially enrolled student in the field. Chemists study the composition of ...s. In 1913 the CRC offered a short (116-page) manual called the ''Rubber Handboo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stromboli
Stromboli ( , ; ) is an island in the Tyrrhenian Sea, off the north coast of Sicily, containing Mount Stromboli, one of the four active volcanoes in Italy. It is one of the seven Aeolian Islands, a volcanic arc north of Sicily, and the mythological home of Aeolus. The island, with an area of , represents the upper third of the volcano. Its population was about 500 . The volcano has erupted many times and is constantly active with minor eruptions, often visible from many points on the island and from the surrounding sea, giving rise to the island's nickname "Lighthouse of the Mediterranean". Etymology The name Stromboli is derived from the Ancient Greek name , () which was derived from (, 'round'), after the volcano's round, conical appearance when seen from a distance. Height and shape Stromboli stands above sea level, and over above the sea floor. The area of Stromboli island is . As of June 2024, there are two active craters at the peak, each with multiple vents show ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
