|
Paul Steinhardt
Paul Joseph Steinhardt (born December 25, 1952) is an American theoretical physicist whose principal research is in cosmology and condensed matter physics. He is currently the Albert Einstein Professor in Science at Princeton University, where he is on the faculty of both the Departments of Physics and of Astrophysical Sciences. Steinhardt is best known for his development of new theories of the origin, evolution and future of the universe. He is also well known for his exploration of a new form of matter, known as quasicrystals, which were thought to exist only as man-made materials until he co-discovered the first known natural quasicrystal in a museum sample. He subsequently led a separate team that followed up that discovery with several more examples of natural quasicrystals recovered from the wilds of the Kamchatka Peninsula in far eastern Russia. Several years later, he and collaborators reported the accidental synthesis of a previously unknown type of quasicrystal in the r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Katie Mack (astrophysicist)
Katherine J. Mack (born 1 May 1981) is a theoretical cosmologist who holds the Hawking Chair in Cosmology and Science Communication at Perimeter Institute. Her academic research investigates dark matter, vacuum decay and the epoch of reionisation. Mack is also a popular science communicator who participates in social media and regularly writes for ''Scientific American'', ''Slate'', ''Sky & Telescope'', ''Time'' and ''Cosmos''. Early life and education Mack became interested in science as a child and built solar-powered cars out of Lego blocks. Her mother is a fan of science fiction, and encouraged Mack to watch ''Star Trek'' and ''Star Wars''. Her grandfather was a student at Caltech and worked on the Apollo 11 mission. She became more interested in spacetime and the Big Bang after attending talks by scientists such as Stephen Hawking. Mack attended California Institute of Technology, and appeared as an extra in the opening credits of the 2001 American comedy film ''Legall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Niels Bohr
Niels Henrik David Bohr (; 7 October 1885 – 18 November 1962) was a Danish physicist who made foundational contributions to understanding atomic structure and quantum theory, for which he received the Nobel Prize in Physics in 1922. Bohr was also a philosopher and a promoter of scientific research. Bohr developed the Bohr model of the atom, in which he proposed that energy levels of electrons are discrete and that the electrons revolve in stable orbits around the atomic nucleus but can jump from one energy level (or orbit) to another. Although the Bohr model has been supplanted by other models, its underlying principles remain valid. He conceived the principle of complementarity: that items could be separately analysed in terms of contradictory properties, like behaving as a wave or a stream of particles. The notion of complementarity dominated Bohr's thinking in both science and philosophy. Bohr founded the Institute of Theoretical Physics at the University of Cope ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Scott Award
John Scott Award, created in 1816 as the John Scott Legacy Medal and Premium, is presented to men and women whose inventions improved the "comfort, welfare, and happiness of human kind" in a significant way. "...the John Scott Medal Fund, established in 1816...". Since 1919 the Board of Directors of City Trusts of Philadelphia provide this award, recommended by an advisory committee. Eugene Garfield is member of the Advisory Committee. In 1822 the first awards were given to thirteen people by the Philadelphia Society for Promoting Agriculture entrusted by the "Philadelphia City Council, Corporation of the city of Philadelphia". The druggist John Scott of Edinburgh organized a $4,000 fund which, after his death in 1815 was administered by a merchant until the first award, a copper medal and "an amount not to exceed twenty dollars", was given in 1822. (At the time, $20 could buy one ox or a 12-volume encyclopedia.) Several hundred recipients have since been selected by the Philadelph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oliver E
Oliver may refer to: Arts, entertainment and literature Books * ''Oliver the Western Engine'', volume 24 in ''The Railway Series'' by Rev. W. Awdry * ''Oliver Twist'', a novel by Charles Dickens Fictional characters * Ariadne Oliver, in the novels of Agatha Christie * Oliver (Disney character) * Oliver Fish, a gay police officer on the American soap opera ''One Life to Live'' * Oliver Hampton, in the American television series ''How to Get Away with Murder'' * Oliver Jones (''The Bold and the Beautiful''), on the American soap opera ''The Bold and the Beautiful'' * Oliver Lightload, in the movie ''Cars'' * Oliver Oken, from ''Hannah Montana'' * Oliver (paladin), a paladin featured in the Matter of France * Oliver Queen, DC Comic book hero also known as the Green Arrow * Oliver (Thomas and Friends character), a locomotive in the Thomas and Friends franchise * Oliver Trask, a controversial minor character from the first season of ''The O.C.'' * Oliver Twist (character ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dirac Medal
The Dirac Medal is the name of four awards in the field of theoretical physics, computational chemistry, and mathematics, awarded by different organizations, named in honour of Professor Paul Dirac, one of the great theoretical physicists of the 20th century. The Dirac Medal and Lecture (University of New South Wales) The first-established prize is the Dirac Medal for the Advancement of Theoretical Physics, awarded by the University of New South Wales, Sydney, Australia, jointly with the Australian Institute of Physics on the occasion of the public Dirac Lecture. The Lecture and the Medal commemorate the visit to the university in 1975 of Professor Dirac, who gave five lectures there. These lectures were subsequently published as a book: ''Directions of Physics'' (Wiley, 1978 – H. Hora and J. Shepanski, eds.). Professor Dirac donated the royalties from this book to the University for the establishment of the Dirac Lecture series. The prize, first awarded in 1979, includes a sil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guggenheim Fellowship
Guggenheim Fellowships are grants that have been awarded annually since by the John Simon Guggenheim Memorial Foundation to those "who have demonstrated exceptional capacity for productive scholarship or exceptional creative ability in the arts." Each year, the foundation issues awards in each of two separate competitions: * One open to citizens and permanent residents of the United States and Canada. * The other to citizens and permanent residents of Latin America and the Caribbean. The Latin America and Caribbean competition is currently suspended "while we examine the workings and efficacy of the program. The U.S. and Canadian competition is unaffected by this suspension." The performing arts are excluded, although composers, film directors, and choreographers are eligible. The fellowships are not open to students, only to "advanced professionals in mid-career" such as published authors. The fellows may spend the money as they see fit, as the purpose is to give fellows "b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Icosahedrite
Icosahedrite is the first known naturally occurring quasicrystal phase. It has the composition Al63Cu24Fe13 and is a mineral approved by the International Mineralogical Association in 2010. Its discovery followed a 10-year-long systematic search by an international team of scientists led by Luca Bindi and Paul J. Steinhardt to find the first natural quasicrystal. It occurs as tiny grains in a small sample labelled "khatyrkite" (catalog number 46407/G, housed in The Museum of Natural History, University of Florence, Italy), collected from an outcrop of weathered serpentinite in the Khatyrka ultramafic zone of the Koryak-Kamchatka area, Koryak Mountains, Russia. The rock sample also contains spinel, diopside, forsterite, nepheline, sodalite, corundum, stishovite, khatyrkite, cupalite and an unnamed AlCuFe alloy. Evidence shows that the sample is actually extraterrestrial in origin, delivered to the Earth by a CV3 carbonaceous chondrite asteroid that dates back 4.5 Gya. A geological ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quasicrystal
A quasiperiodic crystal, or quasicrystal, is a structure that is ordered but not periodic. A quasicrystalline pattern can continuously fill all available space, but it lacks translational symmetry. While crystals, according to the classical crystallographic restriction theorem, can possess only two-, three-, four-, and six-fold rotational symmetries, the Bragg diffraction pattern of quasicrystals shows sharp peaks with other symmetry orders—for instance, five-fold. Aperiodic tilings were discovered by mathematicians in the early 1960s, and, some twenty years later, they were found to apply to the study of natural quasicrystals. The discovery of these aperiodic forms in nature has produced a paradigm shift in the field of crystallography. In crystallography the quasicrystals were predicted in 1981 by a five-fold symmetry study of Alan Lindsay Mackay,—that also brought in 1982, with the crystallographic Fourier transform of a Penrose tiling,Alan L. Mackay, "Crystallography ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Self-interacting Dark Matter
In astrophysics and particle physics, self-interacting dark matter (SIDM) is an alternative class of dark matter particles which have strong interactions, in contrast to the standard cold dark matter model (CDM). SIDM was postulated in 2000 as a solution to the core-cusp problem. In the simplest models of DM self-interactions, a Yukawa-type potential and a force carrier φ mediates between two dark matter particles. On galactic scales, DM self-interaction leads to energy and momentum exchange between DM particles. Over cosmological time scales this results in isothermal cores in the central region of dark matter haloes. If the self-interacting dark matter is in hydrostatic equilibrium, its pressure and density follow: :\nabla P_\chi/\rho_\chi = \nabla \Phi_ = \nabla (\Phi_\chi + \Phi_b) where \Phi_ and \Phi_ are the gravitational potential of the dark matter and a baryon respectively. The equation naturally correlates the dark matter distribution to that of the baryonic matter d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quintessence (physics)
In physics, quintessence is a hypothetical form of dark energy, more precisely a scalar field, postulated as an explanation of the observation of an accelerating rate of expansion of the universe. The first example of this scenario was proposed by Ratra and Peebles (1988) and Wetterich (1988). The concept was expanded to more general types of time-varying dark energy, and the term "quintessence" was first introduced in a 1998 paper by Robert R. Caldwell, Rahul Dave and Paul Steinhardt. It has been proposed by some physicists to be a fifth fundamental force. Quintessence differs from the cosmological constant explanation of dark energy in that it is dynamic; that is, it changes over time, unlike the cosmological constant which, by definition, does not change. Quintessence can be either attractive or repulsive depending on the ratio of its kinetic and potential energy. Those working with this postulate believe that quintessence became repulsive about ten billion years ago, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ekpyrotic Universe
The ekpyrotic universe () is a physical cosmology, cosmological model of the early universe that explains the origin of the large-scale structure of the cosmos. The model has also been incorporated in the cyclic universe theory (or ekpyrotic cyclic universe theory), which proposes a complete cosmological history, both the past and future. Origins The original ekpyrotic model was introduced by Justin Khoury, Burt Ovrut, Paul Steinhardt and Neil Turok in 2001. Steinhardt created the name based on the Ancient Greek word ekpyrosis (ἐκπύρωσις, "conflagration"), which refers to a Stoicism, Stoic cosmological model in which the universe is caught in an eternal cycle of fiery birth, cooling and rebirth. The theory addresses the fundamental question that remains unanswered by the Big Bang inflationary model, "What happened before the Big Bang?" The explanation, according to the ekpyrotic theory, is that the Big Bang was actually a big bounce, a transition from a previous epo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
