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Howard P. Robertson
Howard Percy "Bob" Robertson (January 27, 1903 – August 26, 1961) was an American mathematician and physicist known for contributions related to physical cosmology and the uncertainty principle. He was Professor of Mathematical Physics at the California Institute of Technology and Princeton University. Robertson made important contributions to the mathematics of quantum mechanics, general relativity and differential geometry. Applying relativity to cosmology, he independently developed the concept of an expanding universe. His name is most often associated with the Poynting–Robertson effect, the process by which solar radiation causes a dust mote orbiting a star to lose angular momentum, which he also described in terms of general relativity. During World War II, Robertson served with the National Defense Research Committee (NDRC) and the Office of Scientific Research and Development (OSRD). He served as Technical Consultant to the Secretary of War, the OSRD Liaison Officer i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hoquiam, Washington
Hoquiam ( ) is a city in Grays Harbor County, Washington, United States. It borders the city of Aberdeen at Myrtle Street, with Hoquiam to the west. The two cities share a common economic history in lumbering and exporting, but Hoquiam has maintained its independent identity. It shares a long rivalry with its more populated neighbor, especially in high school sports. Hoquiam (Ho'-kwee-um, or Ho-kwim, to natives) was incorporated on May 21, 1890. Its name comes from a Native-American word meaning "hungry for wood", from the great amount of driftwood at the mouth of the Hoquiam River. The population was 8,776 at the 2020 census. History One of the first logging operations in Hoquiam was established by Ed Campbell in 1872.Van Syckle, Ed. A Brief Historical Sketch of Grays Harbor Washington. Chambers of Commerce of Hoquiam and Aberdeen, Washington, 1942. About 10 years later, Captain Asa M. Simpson, a Pacific Coast mariner and businessman in the lumber industry from San Francisco, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum Mechanics
Quantum mechanics is a fundamental theory in physics that provides a description of the physical properties of nature at the scale of atoms and subatomic particles. It is the foundation of all quantum physics including quantum chemistry, quantum field theory, quantum technology, and quantum information science. Classical physics, the collection of theories that existed before the advent of quantum mechanics, describes many aspects of nature at an ordinary (macroscopic) scale, but is not sufficient for describing them at small (atomic and subatomic) scales. Most theories in classical physics can be derived from quantum mechanics as an approximation valid at large (macroscopic) scale. Quantum mechanics differs from classical physics in that energy, momentum, angular momentum, and other quantities of a bound system are restricted to discrete values ( quantization); objects have characteristics of both particles and waves (wave–particle duality); and there are limits to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Office Of The Secretary Of Defense
The Office of the Secretary of Defense (OSD) is a headquarters-level staff of the United States Department of Defense. It is the principal civilian staff element of the U.S. Secretary of Defense, and it assists the Secretary in carrying out authority, direction and control of the Department of Defense in the exercise of policy development, planning, resource management, fiscal, and program evaluation responsibilities. OSD (along with the Joint Staff) is the Secretary of Defense's support staff for managing the Department of Defense, and it corresponds to what the Executive Office of the President of the U.S. is to the U.S. president for managing the whole of the Executive branch of the federal government. OSD includes the immediate offices of the Secretary (SECDEF) and the Deputy Secretary of Defense (DEPSECDEF), as well as the Under Secretary of Defense for Research and Engineering; Under Secretary of Defense for Acquisition and Sustainment; Under Secretary of Defense for Pol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weapons Systems Evaluation Group
The Weapons Systems Evaluation Group (abbreviated WSEG) was formed in 1949 to carry out Operational Research work for the Joint Chiefs of Staff of the United States Army and the United States Secretary of Defense. The group oversaw the appraisal of weapons used during the Korean War. The group collaborated with Israel in evaluating the effectiveness of Soviet weapons during the Cold War. History The first Research Director was Philip M. Morse, who served a year and a half before returning to MIT in the summer of 1950. From 1957 until 1960 John H. Sides was director of WSEG. Lt. Gen. Harvey T. Alness was director from Sept. 1, 1962 until March 1, 1964. Hugh Everett III worked at the WSEG from 1956 until 1964. Much of his works remains classified. During his time with the WSEG Everett worked on various studies of the Minuteman missile The LGM-30 Minuteman is an American land-based intercontinental ballistic missile (ICBM) in service with the Air Force Global Strike Command. , t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supreme Headquarters Allied Expeditionary Force
Supreme Headquarters Allied Expeditionary Force (SHAEF; ) was the headquarters of the Commander of Allied forces in north west Europe, from late 1943 until the end of World War II. U.S. General Dwight D. Eisenhower was the commander in SHAEF throughout its existence. The position itself shares a common lineage with Supreme Allied Commander Europe and Atlantic, but they are different titles. History during the Second World War Eisenhower transferred from command of the Mediterranean Theater of Operations to command SHAEF, which was formed in Camp Griffiss, Bushy Park, Teddington, London, from December 1943; an adjacent street named Shaef Way, and a gate into the park called Shaef Gate, remain to this day. Southwick House was used as an alternative headquarters near Portsmouth. Its staff took the outline plan for Operation Overlord created by Lieutenant General Sir Frederick E. Morgan, Chief of Staff to the Supreme Allied Commander (Designate) (COSSAC), and Major General Ray Ba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secretary Of War
The secretary of war was a member of the U.S. president's Cabinet, beginning with George Washington's administration. A similar position, called either "Secretary at War" or "Secretary of War", had been appointed to serve the Congress of the Confederation under the Articles of Confederation between 1781 and 1789. Benjamin Lincoln and later Henry Knox held the position. When Washington was inaugurated as the first President under the Constitution, he appointed Knox to continue serving as Secretary of War. The secretary of war was the head of the War Department. At first, he was responsible for all military affairs, including naval affairs. In 1798, the secretary of the Navy was created by statute, and the scope of responsibility for this office was reduced to the affairs of the United States Army. From 1886 onward, the secretary of war was in the line of succession to the presidency, after the vice president of the United States, the Speaker of the House of Representatives, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Office Of Scientific Research And Development
The Office of Scientific Research and Development (OSRD) was an agency of the United States federal government created to coordinate scientific research for military purposes during World War II. Arrangements were made for its creation during May 1941, and it was created formally by Executive Order 8807 on June 28, 1941. It superseded the work of the National Defense Research Committee (NDRC), was given almost unlimited access to funding and resources, and was directed by Vannevar Bush, who reported only to President Franklin Delano Roosevelt. The research was widely varied, and included projects devoted to new and more accurate bombs, reliable detonators, work on the proximity fuze, guided missiles, radar and early-warning systems, lighter and more accurate hand weapons, more effective medical treatments (including work to make penicillin at scale, which was necessary for its use as a drug), more versatile vehicles, and, the most secret of all, the S-1 Section, which later be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Defense Research Committee
The National Defense Research Committee (NDRC) was an organization created "to coordinate, supervise, and conduct scientific research on the problems underlying the development, production, and use of mechanisms and devices of warfare" in the United States from June 27, 1940, until June 28, 1941. Most of its work was done with the strictest secrecy, and it began research of what would become some of the most important technology during World War II, including radar and the atomic bomb. It was superseded by the Office of Scientific Research and Development in 1941, and reduced to merely an advisory organization until it was eventually terminated during 1947. Organization The NDRC was created by an order of President Franklin Delano Roosevelt on June 27, 1940. It was part of the Council of National Defense, which had been created during 1916 to coordinate industry and resources for national security purposes. Vannevar Bush, the director of the Carnegie Institution, had pressed for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing military alliances: the Allies and the Axis powers. World War II was a total war that directly involved more than 100 million personnel from more than 30 countries. The major participants in the war threw their entire economic, industrial, and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources. Aircraft played a major role in the conflict, enabling the strategic bombing of population centres and deploying the only two nuclear weapons ever used in war. World War II was by far the deadliest conflict in human history; it resulted in 70 to 85 million fatalities, mostly among civilians. Tens of millions died due to genocides (including the Holocaust), starvation, ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angular Momentum
In physics, angular momentum (rarely, moment of momentum or rotational momentum) is the rotational analog of linear momentum. It is an important physical quantity because it is a conserved quantity—the total angular momentum of a closed system remains constant. Angular momentum has both a direction and a magnitude, and both are conserved. Bicycles and motorcycles, frisbees, rifled bullets, and gyroscopes owe their useful properties to conservation of angular momentum. Conservation of angular momentum is also why hurricanes form spirals and neutron stars have high rotational rates. In general, conservation limits the possible motion of a system, but it does not uniquely determine it. The three-dimensional angular momentum for a point particle is classically represented as a pseudovector , the cross product of the particle's position vector (relative to some origin) and its momentum vector; the latter is in Newtonian mechanics. Unlike linear momentum, angular m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Radiation
Solar irradiance is the power per unit area (surface power density) received from the Sun in the form of electromagnetic radiation in the wavelength range of the measuring instrument. Solar irradiance is measured in watts per square metre (W/m2) in SI units. Solar irradiance is often integrated over a given time period in order to report the radiant energy emitted into the surrounding environment (joule per square metre, J/m2) during that time period. This integrated solar irradiance is called solar irradiation, solar exposure, solar insolation, or insolation. Irradiance may be measured in space or at the Earth's surface after atmospheric absorption and scattering. Irradiance in space is a function of distance from the Sun, the solar cycle, and cross-cycle changes.Michael Boxwell, ''Solar Electricity Handbook: A Simple, Practical Guide to Solar Energy'' (2012), p. 41–42. Irradiance on the Earth's surface additionally depends on the tilt of the measuring surface, the height ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Expanding Universe
The expansion of the universe is the increase in distance between any two given gravitationally unbound parts of the observable universe with time. It is an intrinsic expansion whereby the scale of space itself changes. The universe does not expand "into" anything and does not require space to exist "outside" it. This expansion involves neither space nor objects in space "moving" in a traditional sense, but rather it is the metric (which governs the size and geometry of spacetime itself) that changes in scale. As the spatial part of the universe's spacetime metric increases in scale, objects become more distant from one another at ever-increasing speeds. To any observer in the universe, it appears that all of space is expanding, and that all but the nearest galaxies (which are bound by gravity) recede at speeds that are proportional to their distance from the observer. While objects within space cannot travel faster than light, this limitation does not apply to the effects of ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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