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Tsvi Piran
Tsvi Piran (born May 6, 1949) is an Israeli theoretical physicist and astrophysicist, best known for his work on Gamma-ray Bursts (GRBs) and on numerical relativity. The recipient of the 2019 EMET prize award in Physics and Space Research. At a time when most astronomers believed that GRBs were galactic (see however an earlier suggestion by Bohdan Paczynski ) with Eichler, Livio and Schramm, Piran proposed that GRBs originate from cosmological neutron star binary mergers, a model that is generally accepted today. During the early nineties when the cosmological vs. galactic debate took place, Piran was one of the strongest and most vocal proponents of cosmological origin, which was confirmed in 1997 with the discovery of cosmological redshifts from GRB's afterglow. Even before the cosmological origin of GRBs was discovered Piran laid the foundation to the generally accepted cosmic fireball model. He suggested that GRBs herald the formation of a newborn black hole. Later o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tel Aviv
Tel Aviv-Yafo ( he, תֵּל־אָבִיב-יָפוֹ, translit=Tēl-ʾĀvīv-Yāfō ; ar, تَلّ أَبِيب – يَافَا, translit=Tall ʾAbīb-Yāfā, links=no), often referred to as just Tel Aviv, is the most populous city in the Gush Dan metropolitan area of Israel. Located on the Israeli coastal plain, Israeli Mediterranean coastline and with a population of , it is the Economy of Israel, economic and Technology of Israel, technological center of the country. If East Jerusalem is considered part of Israel, Tel Aviv is the country's second most populous city after Jerusalem; if not, Tel Aviv is the most populous city ahead of West Jerusalem. Tel Aviv is governed by the Tel Aviv-Yafo Municipality, headed by Mayor Ron Huldai, and is home to many List of diplomatic missions in Israel, foreign embassies. It is a Global city, beta+ world city and is ranked 57th in the 2022 Global Financial Centres Index. Tel Aviv has the List of cities by GDP, third- or fourth-largest e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quasinormal Mode
Quasinormal modes (QNM) are the modes of energy dissipation of a perturbed object or field, ''i.e.'' they describe perturbations of a field that decay in time. Example A familiar example is the perturbation (gentle tap) of a wine glass with a knife: the glass begins to ring, it rings with a set, or superposition, of its natural frequencies — its modes of sonic energy dissipation. One could call these modes ''normal'' if the glass went on ringing forever. Here the amplitude of oscillation decays in time, so we call its modes ''quasi-normal''. To a high degree of accuracy, quasinormal ringing can be approximated by :\psi(t) \approx e^\cos\omega^t where \psi\left(t\right) is the amplitude of oscillation, \omega^ is the frequency, and \omega^ is the decay rate. The quasinormal frequency is described by two numbers, :\omega = \left(\omega^ , \omega^\right) or, more compactly :\psi\left(t\right) \approx \operatorname(e^) :\omega =\omega^ + i\omega^ Here, \mathbf is what is comm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hebrew University Of Jerusalem Alumni
Hebrew (; ; ) is a Northwest Semitic language of the Afroasiatic language family. Historically, it is one of the spoken languages of the Israelites and their longest-surviving descendants, the Jews and Samaritans. It was largely preserved throughout history as the main liturgical language of Judaism (since the Second Temple period) and Samaritanism. Hebrew is the only Canaanite language still spoken today, and serves as the only truly successful example of a dead language that has been revived. It is also one of only two Northwest Semitic languages still in use, with the other being Aramaic. The earliest examples of written Paleo-Hebrew date back to the 10th century BCE. Nearly all of the Hebrew Bible is written in Biblical Hebrew, with much of its present form in the dialect that scholars believe flourished around the 6th century BCE, during the time of the Babylonian captivity. For this reason, Hebrew has been referred to by Jews as '' Lashon Hakodesh'' (, ) since anci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Israeli Astrophysicists
Israeli may refer to: * Something of, from, or related to the State of Israel * Israelis, citizens or permanent residents of the State of Israel * Modern Hebrew, a language * ''Israeli'' (newspaper), published from 2006 to 2008 * Guni Israeli (born 1984), Israeli basketball player See also * Israelites, the ancient people of the Land of Israel * List of Israelis Israelis ( he, ישראלים ''Yiśraʾelim'') are the citizens or permanent residents of the State of Israel, a multiethnic state populated by people of different ethnic backgrounds. The largest ethnic groups in Israel are Jews (75%), foll ... {{disambiguation Language and nationality disambiguation pages ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Living People
Related categories * :Year of birth missing (living people) / :Year of birth unknown * :Date of birth missing (living people) / :Date of birth unknown * :Place of birth missing (living people) / :Place of birth unknown * :Year of death missing / :Year of death unknown * :Date of death missing / :Date of death unknown * :Place of death missing / :Place of death unknown * :Missing middle or first names See also * :Dead people * :Template:L, which generates this category or death years, and birth year and sort keys. : {{DEFAULTSORT:Living people 21st-century people People by status ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1949 Births
Events January * January 1 – A United Nations-sponsored ceasefire brings an end to the Indo-Pakistani War of 1947. The war results in a stalemate and the division of Kashmir, which still continues as of 2022. * January 2 – Luis Muñoz Marín becomes the first democratically elected Governor of Puerto Rico. * January 11 – The first "networked" television broadcasts take place, as KDKA-TV in Pittsburgh, Pennsylvania goes on the air, connecting east coast and mid-west programming in the United States. * January 16 – Şemsettin Günaltay forms the new government of Turkey. It is the 18th government, last One-party state, single party government of the Republican People's Party. * January 17 – The first Volkswagen Beetle, VW Type 1 to arrive in the United States, a 1948 model, is brought to New York City, New York by Dutch businessman Ben Pon Sr., Ben Pon. Unable to interest dealers or importers in the Volkswagen, Pon sells the sample car to pay his ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Institute For Advanced Study
The Institute for Advanced Study (IAS), located in Princeton, New Jersey, in the United States, is an independent center for theoretical research and intellectual inquiry. It has served as the academic home of internationally preeminent scholars, including J. Robert Oppenheimer, Albert Einstein, Hermann Weyl, John von Neumann, and Kurt Gödel, many of whom had emigrated from Europe to the United States. It was founded in 1930 by American educator Abraham Flexner, together with philanthropists Louis Bamberger and Caroline Bamberger Fuld. Despite collaborative ties and neighboring geographic location, the institute, being independent, has "no formal links" with Princeton University. The institute does not charge tuition or fees. Flexner's guiding principle in founding the institute was the pursuit of knowledge for its own sake.Jogalekar. The faculty have no classes to teach. There are no degree programs or experimental facilities at the institute. Research is never contracted or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bryce DeWitt
Bryce Seligman DeWitt (January 8, 1923 – September 23, 2004), was an American theoretical physicist noted for his work in gravitation and quantum field theory. Life He was born Carl Bryce Seligman, but he and his three brothers, including the noted ichthyologist Hugh Hamilton DeWitt, added "DeWitt" from their mother's side of the family, at the urging of their father, in 1950. In the early-1970s, this change of name so angered Felix Bloch that he blocked DeWitt's appointment to Stanford University and DeWitt and his wife Cecile DeWitt-Morette, a mathematical physicist, accepted faculty positions at the University of Texas at Austin. DeWitt served in World War II as a naval aviator. He died September 23, 2004 from pancreatic cancer at the age of 81. He is buried in France, and was survived by his wife and four daughters. Work He pioneered work in the quantization of general relativity and, in particular, developed canonical quantum gravity, manifestly covariant methods ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dennis William Sciama
Dennis William Siahou Sciama, (; 18 November 1926 – 18/19 December 1999) was a British physicist who, through his own work and that of his students, played a major role in developing British physics after the Second World War. He was the PhD supervisor to many famous cosmologists, including Stephen Hawking, Martin Rees and David Deutsch; he is considered one of the fathers of modern cosmology. Education and early life Sciama was born in Manchester, England, the son of Nelly Ades and Abraham Sciama. He was of Syrian-Jewish ancestry — his father born in Manchester and his mother born in Egypt, but both traced their roots back to Aleppo, Syria. Sciama earned his PhD in 1953 at the University of Cambridge supervised by Paul Dirac, with a dissertation on Mach's principle and inertia. His work later influenced the formulation of scalar-tensor theories of gravity. Career and research Sciama taught at Cornell University, King's College London, Harvard University and the Univer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cosmic Censorship Hypothesis
The weak and the strong cosmic censorship hypotheses are two mathematical conjectures about the structure of gravitational singularities arising in general relativity. Singularities that arise in the solutions of Einstein's equations are typically hidden within event horizons, and therefore cannot be observed from the rest of spacetime. Singularities that are not so hidden are called ''naked''. The weak cosmic censorship hypothesis was conceived by Roger Penrose in 1969 and posits that no naked singularities exist in the universe. Basics Since the physical behavior of singularities is unknown, if singularities can be observed from the rest of spacetime, causality may break down, and physics may lose its predictive power. The issue cannot be avoided, since according to the Penrose–Hawking singularity theorems, singularities are inevitable in physically reasonable situations. Still, in the absence of naked singularities, the universe, as described by the general theory of relativi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Numerical Relativity
Numerical relativity is one of the branches of general relativity that uses numerical methods and algorithms to solve and analyze problems. To this end, supercomputers are often employed to study black holes, gravitational waves, neutron stars and many other phenomena governed by Einstein's theory of general relativity. A currently active field of research in numerical relativity is the simulation of relativistic binaries and their associated gravitational waves. Overview A primary goal of numerical relativity is to study spacetimes whose exact form is not known. The spacetimes so found computationally can either be fully dynamical, stationary or static and may contain matter fields or vacuum. In the case of stationary and static solutions, numerical methods may also be used to study the stability of the equilibrium spacetimes. In the case of dynamical spacetimes, the problem may be divided into the initial value problem and the evolution, each requiring different methods. Numeri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
