|
J. Robert Oppenheimer
J. Robert Oppenheimer (; April 22, 1904 – February 18, 1967) was an American theoretical physicist. He was the director of the Los Alamos Laboratory during World War II, and is often credited as the "father of the atomic bomb" for his role in the Manhattan Project, the research and development undertaking that created the first nuclear weapons. Oppenheimer attended Harvard University, where he earned a bachelor's degree in chemistry in 1925. He studied physics at the University of Cambridge and University of Göttingen, where he received his PhD in 1927. He held academic positions at the University of California, Berkeley, and the California Institute of Technology, and made significant contributions to theoretical physics, including in quantum mechanics and nuclear physics. During World War II, he was recruited to work on the Manhattan Project, and in 1943 was appointed as director of the Los Alamos Laboratory in New Mexico, tasked with developing the weapons. Oppenheimer's ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Princeton, New Jersey
Princeton is a municipality with a borough form of government in Mercer County, in the U.S. state of New Jersey. It was established on January 1, 2013, through the consolidation of the Borough of Princeton and Princeton Township, both of which are now defunct. Centrally located within the Raritan Valley region, Princeton is a regional commercial hub for the Central New Jersey region and a commuter town in the New York metropolitan area.New York-Newark, NY-NJ-CT-PA Combined Statistical Area . Accessed December 5, 2020. As of the |
Willis Eugene Lamb
Willis Eugene Lamb Jr. (; July 12, 1913 – May 15, 2008) was an American physicist who won the Nobel Prize in Physics in 1955 "for his discoveries concerning the fine structure of the hydrogen spectrum." The Nobel Committee that year awarded half the prize to Lamb and the other half to Polykarp Kusch, who won "for his precision determination of the magnetic moment of the electron." Lamb was able to determine precisely a surprising shift in electron energies in a hydrogen atom (see Lamb shift). Lamb was a professor at the University of Arizona College of Optical Sciences. Biography Lamb was born in Los Angeles, California, United States and attended Los Angeles High School. First admitted in 1930, he received a Bachelor of Science in Chemistry from the University of California, Berkeley in 1934. For theoretical work on scattering of neutrons by a crystal, guided by J. Robert Oppenheimer, he received the Ph.D. in physics in 1938. Because of limited computational methods availabl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enrico Fermi Award
The Enrico Fermi Award is a scientific award conferred by the President of the United States. It is awarded to honor scientists of international stature for their lifetime achievement in the development, use, or production of energy. It was established in 1956 by the United States Department of Energy in memorial of Italian-American physicist Enrico Fermi and his work in the development of nuclear power. The recipient of the award receives $100,000, a certificate signed by the President and the Secretary of Energy, and a gold medal featuring the likeness of Enrico Fermi. Previous winners SourceUS Department of Energy See also * List of engineering awards * Prizes named after people * List of things named after Enrico Fermi * Vannevar Bush Award The National Science Board established the Vannevar Bush Award ( ) in 1980 to honor Vannevar Bush's unique contributions to public service. The annual award recognizes an individual who, through public service activities in science ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medal For Merit
The Medal for Merit was, during the period it was awarded, the highest civilian decoration of the United States. It was awarded by the President of the United States to civilians who "distinguished themselves by exceptionally meritorious conduct in the performance of outstanding services" in the war effort "since the proclamation of an emergency by the President on September 8, 1939". Awards to civilians of foreign nations were eligible "only for the performance of exceptionally meritorious or courageous act or acts in furtherance of the war efforts of the United Nations." The medal is made of gold-finished bronze and enamel and is worn on the left chest from a ribbon. History The Medal for Merit was created by Public Law 77-671 and its awarding codified by Executive Order 9286 - Medal for Merit on , later amended and restated by Executive Order 9857A of . Created during World War II, and awarded to "civilians of the nations prosecuting the war under the joint declaration of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Born–Oppenheimer Approximation
In quantum chemistry and molecular physics, the Born–Oppenheimer (BO) approximation is the best-known mathematical approximation in molecular dynamics. Specifically, it is the assumption that the wave functions of atomic nuclei and electrons in a molecule can be treated separately, based on the fact that the nuclei are much heavier than the electrons. Due to the larger relative mass of a nucleus compared to an electron, the coordinates of the nuclei in a system are approximated as fixed, while the coordinates of the electrons are dynamic. The approach is named after Max Born and J. Robert Oppenheimer who proposed it in 1927, in the early period of quantum mechanics. The approximation is widely used in quantum chemistry to speed up the computation of molecular wavefunctions and other properties for large molecules. There are cases where the assumption of separable motion no longer holds, which make the approximation lose validity (it is said to "break down"), but even then t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oppenheimer–Phillips Process
The Oppenheimer–Phillips process or strip reaction is a type of deuteron-induced nuclear reaction. In this process the neutron half of an energetic deuteron (a stable isotope of hydrogen with one proton and one neutron) fuses with a target nucleus, transmuting the target to a heavier isotope while ejecting a proton. An example is the nuclear transmutation of carbon-12 to carbon-13. The process allows a nuclear interaction to take place at lower energies than would be expected from a simple calculation of the Coulomb barrier between a deuteron and a target nucleus. This is because, as the deuteron approaches the positively charged target nucleus, it experiences a charge polarization where the "proton-end" faces away from the target and the "neutron-end" faces towards the target. The fusion proceeds when the binding energy of the neutron and the target nucleus exceeds the binding energy of the deuteron itself; the proton formerly in the deuteron is then repelled from the new, he ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tolman–Oppenheimer–Volkoff Limit
The Tolman–Oppenheimer–Volkoff limit (or TOV limit) is an upper bound to the mass of cold, nonrotating neutron stars, analogous to the Chandrasekhar limit for white dwarf stars. If the mass of the said star reaches the limit it will collapse to a denser form. Theoretical work in 1996 placed the limit at approximately 1.5 to 3.0 solar masses, corresponding to an original stellar mass of 15 to 20 solar masses; additional work in the same year gave a more precise range of 2.2 to 2.9 solar masses. Observations of GW170817, the first gravitational wave event due to merging neutron stars (which are thought to have collapsed into a black hole within a few seconds after merging), placed the limit at close to 2.17 (solar masses). This value was inconsistent with short gamma-ray burst X-ray plateau data however, which suggested a value of ''M''TOV = 2.37 . Reanalysis of the GW170817 event data in 2019 resulted in a higher value of ''M''TOV = 2.3 . If GW ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tolman–Oppenheimer–Volkoff Equation
In astrophysics, the Tolman–Oppenheimer–Volkoff (TOV) equation constrains the structure of a spherically symmetric body of isotropic material which is in static gravitational equilibrium, as modelled by general relativity. The equation is :\frac=-\frac\rho\left(1+\frac\right)\left(1+\frac\right)\left(1-\frac\right)^ Here, r is a radial coordinate, and \rho(r) and P(r) are the density and pressure, respectively, of the material at radius r. The quantity m(r), the total mass within r, is discussed below. The equation is derived by solving the Einstein equations for a general time-invariant, spherically symmetric metric. For a solution to the Tolman–Oppenheimer–Volkoff equation, this metric will take the form :ds^2=e^ c^2 \,dt^2 - \left(1-\frac\right)^ \,dr^2 - r^2\left(d\theta^2 + \sin^2 \theta \,d\phi^2\right) where \nu(r) is determined by the constraint :\frac=- \left(\frac \right) \frac When supplemented with an equation of state, F(\rho,P)=0, which relates den ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Weapons
A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission bomb) or a combination of fission and fusion reactions (thermonuclear bomb), producing a nuclear explosion. Both bomb types release large quantities of energy from relatively small amounts of matter. The first test of a fission ("atomic") bomb released an amount of energy approximately equal to . The first thermonuclear ("hydrogen") bomb test released energy approximately equal to . Nuclear bombs have had yields between 10 tons TNT (the W54) and 50 megatons for the Tsar Bomba (see TNT equivalent). A thermonuclear weapon weighing as little as can release energy equal to more than . A nuclear device no larger than a conventional bomb can devastate an entire city by blast, fire, and radiation. Since they are weapons of mass destruction, the proliferation of nuclear weapons is a focus of international relations policy. Nuclear weapons have been deployed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
George Volkoff
George Michael Volkoff, (February 23, 1914 – April 24, 2000) was a Russian-Canadian physicist and academic who helped, with J. Robert Oppenheimer, predict the existence of neutron stars before they were discovered. Early life He was born in Moscow. His father was a Russian engineer who emigrated to Vancouver, British Columbia, Canada in 1924. Unable to find work, his father moved the family to Harbin, Manchuria in 1927. His mother died soon after moving to Harbin. In 1936, Volkoff's father returned to Russia but was exiled to the arctic camps as part of the Great Purge where he would die. Education Volkoff returned to Vancouver and entered the University of British Columbia where he received a Bachelor of Arts in physics in 1934 and a Master of Arts degree in 1936. He then studied with J. Robert Oppenheimer at the University of California, Berkeley where he published his paper "On Massive Neutron Cores" and earned his Ph.D. in 1940. Academic In 1940, he joined the physic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hartland Snyder
Hartland Sweet Snyder (1913, Salt Lake City – 1962) was an American physicist who along with Robert Oppenheimer calculated the gravitational collapse of a pressure-free sphere of dust particles as described by Einstein's general relativity, and found they contracted onto a radial distance, the Schwarzschild radius. It was later interpreted as the particles ending in the particles disappearing beneath the 'event horizon' associated with a Black Hole singularity. In recent years, it was shown by Trevor Marshall that the particle trajectories end in a shell of infinite density at the 'event horizon' radius, supporting the shell collapsar as endpoint. Snyder’s argument that the “star thus tends to close itself off from any communication with a distant observer” which is quoted as an early inference of a Black Hole, does not follow from his model. Only the very surface of the infinite density shell could reflect or emit radiation and solutions without a density singularity are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Melba Phillips
Melba Newell Phillips (February 1, 1907 – November 8, 2004) was an American physicist and pioneer science educator. One of the first doctoral students of J. Robert Oppenheimer at the University of California, Berkeley, Phillips completed her Ph.D. in 1933, a time when few women pursued careers in science. In 1935 Oppenheimer and Phillips published their description of the Oppenheimer–Phillips process, an early contribution to nuclear physics that explained the behavior of accelerated nuclei of radioactive hydrogen atoms. Phillips was also known for refusing to cooperate with a U.S. Senate judiciary subcommittee's investigation on internal security during the McCarthy era that led to her dismissal from her professorship at Brooklyn College, where she was a professor of science from 1938 until 1952. (The college publicly and personally apologized to Phillips for the dismissal in 1987.) Phillips also taught at the University of Minnesota (1941–44) and served as associate direc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Medal For Merit")
