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Ivor Robinson (physicist)
Ivor Robinson (October 7, 1923 – May 27, 2016) was a British-American mathematical physicist, born and educated in England, noted for his important contributions to the theory of relativity. He was a principal organizer of the Texas Symposium on Relativistic Astrophysics. Biography Born in Liverpool, October 7, 1923, "into a comfortable Jewish middle-class family", Ivor Robinson read mathematics at Trinity College, Cambridge, as an undergraduate, where he was influenced by Abram Samoilovitch Besicovitch. He took his B.A. in Mathematics from the University of Cambridge in 1947. His first academic placements were at University College of Wales, King's College London, University of North Carolina, University of Hamburg, Syracuse University and Cornell University. Alfred Schild was developing a department strong in relativity at Austin, Texas, when a second Texas center for relativity research was proposed. Lloyd Berkner was directing the Southwest Center for Advanced Studies at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lloyd Berkner
Lloyd Viel Berkner (February 1, 1905 – June 4, 1967) was an American physicist and engineer. He was one of the inventors of the measuring device that since has become standard at ionospheric stations because it measures the height and electron density of the ionosphere. The data obtained in the worldwide net of such instruments were important for the developing theory of short wave radio propagation to which Berkner himself gave important contributions. Berkner was elected to the United States National Academy of Sciences in 1948. He was president of Associated Universities, Inc. from 1951 to 1960. Later he investigated the development of the Earth's atmosphere. Since he needed data from the whole world, he proposed the International Geophysical Year in 1950. At that time, the IGY was the largest cooperative study of the Earth ever undertaken. Berkner was elected a Fellow of the American Academy of Arts and Sciences and a member of the American Philosophical Society in 1956 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red Shift
In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light). The opposite change, a decrease in wavelength and increase in frequency and energy, is known as a blueshift. The terms derive from the colours red and blue which form the extremes of the visible light spectrum. Three forms of redshift occur in astronomy and cosmology: Doppler redshifts due to the relative motions of radiation sources, gravitational redshift as radiation escapes from gravitational potentials, and cosmological redshifts of all light sources proportional to their distances from Earth, a fact known as Hubble's law that implies the universe is expanding. All redshifts can be understood under the umbrella of frame transformation laws. Gravitational waves, which also travel at the speed of light, are subject to the same redshift phenomena. The value of a redshift is often denoted by the letter , co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jesse Greenstein
Jesse Leonard Greenstein (October 15, 1909 – October 21, 2002) was an American astronomer. His parents were Maurice G. and Leah Feingold. He earned a Ph.D, with thesis advisor Donald H. Menzel, from Harvard University in 1937, having started there at age 16. Before leaving Harvard, Greenstein was involved in a project with Fred Lawrence Whipple to explain Karl Jansky's discovery of radio waves from the Milky Way and to propose a source. He began his professional career at Yerkes Observatory under Otto Struve and later went to Caltech. With Louis G. Henyey he invented a new spectrograph and a wide-field camera. He directed the Caltech astronomy program until 1972 and later did classified work on military reconnaissance satellites. With Leverett Davis, Jr, he demonstrated in 1949 that the magnetic field in our galaxy is aligned with the spiral arms. His theoretical work with Davis was based on the conclusion just reached by William A. Hiltner that the recently detec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maarten Schmidt
Maarten Schmidt (28 December 1929 – 17 September 2022) was a Dutch-born American astronomer who first measured the distances of quasars. He was the first astronomer to identify a quasar, and so was pictured on the March cover of ''Time'' magazine in 1966. Early life Schmidt was born in Groningen, The Netherlands, on 28 December 1929. His father, Wilhelm, worked as an accountant for the Dutch government; his mother, Annie Wilhelmina (Haringhuizen), was a housewife. Schmidt studied math and physics at the University of Groningen, graduating with a bachelor's degree in 1949 before obtaining a master's degree the following year. He then commenced doctoral studies at Leiden University under Jan Oort. Schmidt was awarded a Doctor of Philosophy from Leiden Observatory in 1956. Career After completing his doctorate, Schmidt resided in the United States for two years on a Carnegie Fellowship. He returned briefly to the Netherlands, but ultimately emigrated to the US on a perma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Astronomy
Radio astronomy is a subfield of astronomy that studies Astronomical object, celestial objects using radio waves. It started in 1933, when Karl Jansky at Bell Telephone Laboratories reported radiation coming from the Milky Way. Subsequent observations have identified a number of different sources of radio emission. These include stars and galaxy, galaxies, as well as entirely new classes of objects, such as Radio galaxy, radio galaxies, quasars, pulsars, and Astrophysical maser, masers. The discovery of the cosmic microwave background radiation, regarded as evidence for the Big Bang, Big Bang theory, was made through radio astronomy. Radio astronomy is conducted using large Antenna (radio), radio antennas referred to as ''radio telescopes'', that are either used alone, or with multiple linked telescopes utilizing the techniques of Astronomical interferometer, radio interferometry and aperture synthesis. The use of interferometry allows radio astronomy to achieve high angular resolu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astrophysical Sciences
Astrophysics is a science that employs the methods and principles of physics and chemistry in the study of astronomical objects and phenomena. As one of the founders of the discipline, James Keeler, said, astrophysics "seeks to ascertain the nature of the heavenly bodies, rather than their positions or motions in space—''what'' they are, rather than ''where'' they are", which is studied in celestial mechanics. Among the subjects studied are the Sun (solar physics), other stars, galaxies, extrasolar planets, the interstellar medium, and the cosmic microwave background. Emissions from these objects are examined across all parts of the electromagnetic spectrum, and the properties examined include luminosity, density, temperature, and chemical composition. Because astrophysics is a very broad subject, ''astrophysicists'' apply concepts and methods from many disciplines of physics, including classical mechanics, electromagnetism, statistical mechanics, thermodynamics, quantum mec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Twistor Theory
In theoretical physics, twistor theory was proposed by Roger Penrose in 1967 as a possible path to quantum gravity and has evolved into a widely studied branch of theoretical and mathematical physics. Penrose's idea was that twistor space should be the basic arena for physics from which space-time itself should emerge. It has led to powerful mathematical tools that have applications to differential and integral geometry, nonlinear differential equations and representation theory, and in physics to general relativity, quantum field theory, and the theory of scattering amplitudes. Twistor theory arose in the context of the rapidly expanding mathematical developments in Einstein's theory of general relativity in the late 1950s and in the 1960s and carries a number of influences from that period. In particular, Roger Penrose has credited Ivor Robinson as an important early influence in the development of twistor theory, through his construction of so-called ''Robinson congruences ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Roger Penrose
Sir Roger Penrose (born 8 August 1931) is an English mathematician, mathematical physicist, Philosophy of science, philosopher of science and Nobel Prize in Physics, Nobel Laureate in Physics. He is Emeritus Rouse Ball Professor of Mathematics in the University of Oxford, an emeritus fellow of Wadham College, Oxford, and an honorary fellow of St John's College, Cambridge, and University College London. Penrose has contributed to the mathematical physics of general relativity and physical cosmology, cosmology. He has received several prizes and awards, including the 1988 Wolf Prize in Physics, which he shared with Stephen Hawking for the Penrose–Hawking singularity theorems, and the 2020 Nobel Prize in Physics "for the discovery that black hole formation is a robust prediction of the general theory of relativity". He won the Royal Society Prizes for Science Books, Royal Society Science Books Prize for ''The Emperor's New Mind'' (1989), which outlines his views on physics and con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bel–Robinson Tensor
In general relativity and differential geometry, the Bel–Robinson tensor is a tensor defined in the abstract index notation by: :T_=C_C_ ^ _ ^ + \frac\epsilon_^ \epsilon_^_ C_ C_^_^ Alternatively, :T_ = C_C_ ^ _ ^ - \frac g_ C_ C^_^ where C_ is the Weyl tensor. It was introduced by Lluís Bel in 1959. The Bel–Robinson tensor is constructed from the Weyl tensor in a manner analogous to the way the electromagnetic stress–energy tensor is built from the electromagnetic tensor. Like the electromagnetic stress–energy tensor, the Bel–Robinson tensor is totally symmetric and traceless: :\begin T_ &= T_ \\ T^_ &= 0 \end In general relativity, there is no unique definition of the local energy of the gravitational field. The Bel–Robinson tensor is a possible definition for local energy, since it can be shown that whenever the Ricci tensor In differential geometry, the Ricci curvature tensor, named after Gregorio Ricci-Curbastro, is a geometric object which is determined ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Professor Emeritus
''Emeritus/Emerita'' () is an honorary title granted to someone who retirement, retires from a position of distinction, most commonly an academic faculty position, but is allowed to continue using the previous title, as in "professor emeritus". In some cases, the term is conferred automatically upon all persons who retire at a given rank, but in others, it remains a mark of distinguished performance (usually in the area of research) awarded selectively on retirement. It is also used when a person of distinction in a profession retires or hands over the position, enabling their former rank to be retained in their title. The term ''emeritus'' does not necessarily signify that a person has relinquished all the duties of their former position, and they may continue to exercise some of them. In descriptions of deceased professors emeriti listed at U.S. universities, the title ''emeritus'' is replaced by an indication of the years of their appointments, except in Obituary, obituaries, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Texas At Dallas
The University of Texas at Dallas (UTD or UT Dallas) is a public research university in Richardson, Texas, United States. It is the northernmost institution of the University of Texas System. It was initially founded in 1961 as a private research arm of Texas Instruments. The university is classified among "R1: Doctoral Universities – Very high research activity". It is associated with four Nobel Prizes and has members of the National Academy of Sciences and National Academy of Engineering on its faculty with research projects including the areas of Space Science, Bioengineering, Cybersecurity, Nanotechnology, and Behavioral and Brain Sciences. UT Dallas offers more than 140 academic programs across its seven schools and hosts more than 50 research centers and institutes. While the main campus is officially under the city jurisdiction of Richardson, one-third of it is within the borders of Dallas County. UTD also operates several locations in downtown Dallas – this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
