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Forest Ray Moulton
Forest Ray Moulton (April 29, 1872 – December 7, 1952) was an American astronomer. He was the brother of Harold G. Moulton, a noted economist. Biography He was born in Le Roy, Michigan, and was educated at Albion College. After graduating in 1894 ( A.B.), he pursued graduate studies at the University of Chicago and gained a Ph.D. in 1899. At the University of Chicago he was associate in astronomy (1898–1900), instructor (1900–03), assistant professor (1903–08), associate professor (1908–12), and professor after 1912. He is noted for being a proponent, along with Thomas Chamberlin, of the Chamberlin–Moulton planetesimal hypothesis that the planets coalesced from smaller bodies they termed planetesimals. Their hypothesis called for the close passage of another star to trigger this condensation, a concept that has since fallen out of favor. In the first decades of the twentieth century, some additional small satellites were discovered to be in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Le Roy, Michigan
LeRoy is a village in Osceola County of the U.S. state of Michigan. The population was 256 at the 2010 census. The village is located within LeRoy Township. History A post office in LeRoy has been in operation since 1871, with James E. Bevins serving as postmaster from 1871 to 1895. In 1871 S.L. Kimball, M. Westfall and James Bevins settled in the area, the village of LeRoy was incorporated by an act of the State Legislature on February 2, 1873. The village was named for LeRoy Carr, a land agent representing the federal government in the area. Geography According to the United States Census Bureau, the village has a total area of , all land. Demographics 2010 census As of the census of 2010, there were 256 people, 97 households, and 68 families residing in the village. The population density was . There were 111 housing units at an average density of . The racial makeup of the village was 96.1% White, 1.6% African American, 0.8% Native American, and 1.6% from two or more ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Planetesimal
Planetesimals () are solid objects thought to exist in protoplanetary disks and debris disks. Believed to have formed in the Solar System about 4.6 billion years ago, they aid study of its formation. Formation A widely accepted theory of planet formation, the planetesimal hypothesis of Viktor Safronov, states that planets form from cosmic dust grains that collide and stick to form ever-larger bodies. Once a body reaches around a kilometer in size, its constituent grains can attract each other directly through mutual gravity, enormously aiding further growth into moon-sized protoplanets. Smaller bodies must instead rely on Brownian motion or turbulence to cause the collisions leading to sticking. The mechanics of collisions and mechanisms of sticking are intricate. Alternatively, planetesimals may form in a very dense layer of dust grains that undergoes a collective gravitational instability in the mid-plane of a protoplanetary disk—or via the concentration and gravitatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Katherine Johnson
Creola Katherine Johnson (; August 26, 1918February 24, 2020) was an American mathematician whose calculations of orbital mechanics as a NASA employee were critical to the success of the first and subsequent U.S. crewed spaceflights.* During her 33-year career at NASA and its predecessor, she earned a reputation for mastering complex manual calculations and helped pioneer the use of computers to perform the tasks. The space agency noted her "historical role as one of the first African-American women to work as a NASA scientist". Johnson's work included calculating trajectories, launch windows, and emergency return paths for Project Mercury spaceflights, including those for astronauts Alan Shepard, the first American in space, and John Glenn, the first American in orbit, and rendezvous paths for the Apollo Lunar Module and command module on flights to the Moon. Her calculations were also essential to the beginning of the Space Shuttle program, and she worked on plans for a m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hidden Figures
''Hidden Figures'' is a 2016 American Biographical film, biographical Drama (film and television), drama film directed by Theodore Melfi and written by Melfi and Allison Schroeder. It is loosely based on the 2016 non-fiction Hidden Figures (book), book of the same name by Margot Lee Shetterly about three female African-American mathematicians: Katherine Johnson, Katherine Goble Johnson (Taraji P. Henson), Dorothy Vaughan (Octavia Spencer), and Mary Jackson (engineer), Mary Jackson (Janelle Monáe), who worked at NASA during the Space Race. Other stars include Kevin Costner, Kirsten Dunst, Jim Parsons, Mahershala Ali, Aldis Hodge, and Glen Powell. Principal photography began in March 2016 in Atlanta, Atlanta, Georgia, and wrapped up in May 2016. Other filming locations included several other locations in Georgia (U.S. state), Georgia, including East Point, Georgia, East Point, Canton, Georgia, Canton, Monroe, Georgia, Monroe, Columbus, Georgia, Columbus, and Madison, Georgia, Mad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnum Opus
A masterpiece, , or ; ; ) is a creation that has been given much critical praise, especially one that is considered the greatest work of a person's career or a work of outstanding creativity, skill, profundity, or workmanship. Historically, a "masterpiece" was a work of a very high standard produced by an apprentice to obtain full membership, as a "master", of a guild or academy in various areas of the visual arts and crafts. Etymology The form ''masterstik'' is recorded in English or Scots in a set of Aberdeen guild regulations dated to 1579, whereas ''masterpiece'' is first found in 1605, already outside a guild context, in a Ben Jonson play. ''Masterprize'' was another early variant in English. In English, the term rapidly became used in a variety of contexts for an exceptionally good piece of creative work, and was "in early use, often applied to man as the 'masterpiece' of God or Nature". History Originally, the term ''masterpiece'' referred to a piece of work ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World War I
World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting took place mainly in European theatre of World War I, Europe and the Middle Eastern theatre of World War I, Middle East, as well as in parts of African theatre of World War I, Africa and the Asian and Pacific theatre of World War I, Asia-Pacific, and in Europe was characterised by trench warfare; the widespread use of Artillery of World War I, artillery, machine guns, and Chemical weapons in World War I, chemical weapons (gas); and the introductions of Tanks in World War I, tanks and Aviation in World War I, aircraft. World War I was one of the List of wars by death toll, deadliest conflicts in history, resulting in an estimated World War I casualties, 10 million military dead and more than 20 million wounded, plus some 10 million civilian de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aberdeen Proving Ground
Aberdeen Proving Ground (APG) is a U.S. Army facility located adjacent to Aberdeen, Harford County, Maryland, United States. More than 7,500 civilians and 5,000 military personnel work at APG. There are 11 major commands among the tenant units, including: * United States Army Communications-Electronics Command (CECOM) * United States Army Combat Capabilities Development Command (CCDC) * United States Army Test and Evaluation Command (ATEC) * Edgewood Arsenal * Adelphi Laboratory Center ** The Army Reserve Information Operations Command ** Unified Cross Domain Services Management Office ** HQ, U.S. Army Contracting Command (Army Contracting Command –APG, Adelphi Contracting Division) ** U.S. Army 93rd Signal Network - Network Enterprise Center ** Logistics Readiness Center ** U.S. Army Cyber Operation Group – 335th Signal Command ** Blossom Point Research Facility History APG is the U.S. Army's oldest active proving ground, established on October 20, 1917, six months aft ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Theory Of Relativity
The theory of relativity usually encompasses two interrelated physics theories by Albert Einstein: special relativity and general relativity, proposed and published in 1905 and 1915, respectively. Special relativity applies to all physical phenomena in the absence of gravity. General relativity explains the law of gravitation and its relation to the forces of nature. It applies to the cosmological and astrophysical realm, including astronomy. The theory transformed theoretical physics and astronomy during the 20th century, superseding a 200-year-old theory of mechanics created primarily by Isaac Newton. It introduced concepts including 4-dimensional spacetime as a unified entity of space and time, relativity of simultaneity, kinematic and gravitational time dilation, and length contraction. In the field of physics, relativity improved the science of elementary particles and their fundamental interactions, along with ushering in the nuclear age. With relativity, cosmolog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moulton Plane
In incidence geometry, the Moulton plane is an example of an affine plane in which Desargues's theorem does not hold. It is named after the American astronomer Forest Ray Moulton. The points of the Moulton plane are simply the points in the real plane R2 and the lines are the regular lines as well with the exception that for lines with a negative slope, the slope doubles when they pass the ''y''-axis. Formal definition The Moulton plane is an incidence structure \mathfrak M=\langle P, G,\textrm I\rangle, where P denotes the set of points, G the set of lines and \textrm I the incidence relation "lies on": : P:=\mathbb R^2 \, : G:=(\mathbb R \cup \) \times \mathbb R, \infty is just a formal symbol for an element \not\in\mathbb R. It is used to describe vertical lines, which you may think of as lines with an infinitely large slope. The incidence relation is defined as follows: For p = (x, y) \in P and g = (m, b) \in G we have : p\,\textrm I\,g\iff\begin x=b&\textm=\infty\\ y=\frac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adams–Moulton Methods
Linear multistep methods are used for the numerical solution of ordinary differential equations. Conceptually, a numerical method starts from an initial point and then takes a short step forward in time to find the next solution point. The process continues with subsequent steps to map out the solution. Single-step methods (such as Euler's method) refer to only one previous point and its derivative to determine the current value. Methods such as Runge–Kutta take some intermediate steps (for example, a half-step) to obtain a higher order method, but then discard all previous information before taking a second step. Multistep methods attempt to gain efficiency by keeping and using the information from previous steps rather than discarding it. Consequently, multistep methods refer to several previous points and derivative values. In the case of ''linear'' multistep methods, a linear combination of the previous points and derivative values is used. Definitions Numerical methods ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moulton (crater)
Moulton is a crater on the Moon's far side, just beyond the south-southwestern limb as seen from the Earth. The crater is attached to the southern edge of Chamberlin, and it lies at the northern terminus of the Vallis Schrödinger. There is a cleft in the shared rim between Chamberlin and Moulton. This is a worn crater with an outer rim that is not quite circular. There are straight lengths in the rim to the west and northeast, as well as the common rim shared with Chamberlin to the north. Attached to the eastern outer rim is the satellite crater Moulton H. The interior floor has been resurfaced, although the albedo is not as low as the lava Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a Natural satellite, moon onto its surface. Lava may be erupted at a volcano or through a Fissure vent, fractu ...-flooded interior of Chamberlin. There are no craters of note on Moulton's rim or within ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Academy Of Arts And Sciences
The American Academy of Arts and Sciences (The Academy) is one of the oldest learned societies in the United States. It was founded in 1780 during the American Revolution by John Adams, John Hancock, James Bowdoin, Andrew Oliver, and other Founding Fathers of the United States. It is headquartered in Cambridge, Massachusetts. Membership in the academy is achieved through a nominating petition, review, and election process. The academy's quarterly journal, '' Dædalus'', is published by the MIT Press on behalf of the academy, and has been open-access since January 2021. The academy also conducts multidisciplinary public policy research. Laurie L. Patton has served as President of the Academy since January 2025. History The Academy was established by the Massachusetts legislature on May 4, 1780, charted in order "to cultivate every art and science which may tend to advance the interest, honor, dignity, and happiness of a free, independent, and virtuous people." The sixty-tw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
