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Chris Hirata
Christopher Michael Hirata (born November 30, 1982) is an American cosmologist and astrophysicist. Hirata was 13 years old when he won the gold medal in 1996 at the International Physics Olympiad. He received a bachelor's degree in Physics at Caltech in 2001, at the age of 18. He received his PhD under the supervision of Uroš Seljak in 2005 from Princeton University in Astrophysics (thesis: "Weak Gravitational Lensing Theory and Data Analysis"). From 2005 to 2007 he was a visiting scholar at the Institute for Advanced Study. From 2006 to 2012 he was assistant professor and then full professor at Caltech before moving to the Ohio State University the following academic year in the same capacity. He is currently a professor at OSU's Center for Cosmology and AstroParticle Physics (CCAPP). Research Hirata's research emphasis is Cosmic Microwave Background (CMB), Dark energy and accelerating expansion of the universe, galaxy clusters and the large-scale structure of the universe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lake Wildwood, California
Lake Wildwood is a census-designated place (CDP) in Nevada County, California, United States. The population was 4,991 at the 2010 census, up from 4,868 at the 2000 census. Lake Wildwood is mainly a gated community and news about the CDP is published in a twice a month newspaper''The Wildwood Independent''.Local businesses and residences are listed in the annual "Penn Valley Area Directory" published b"Pine Tree Press". History Lake Wildwood was laid out by property developers in the 1960s. In September 1988, the 49er Fire was accidentally started by a homeless and schizophrenic local man near Highway 49. The fire went on to burn well over a hundred homes and more than 33,000 acres in Nevada County, including many homes in the Lake Wildwood area. Geography Lake Wildwood is located at (39.234885, -121.203026). According to the United States Census Bureau, the CDP has a total area of , of which is land and (12.89%) is water. Demographics 2010 The 2010 United States Cens ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galaxy Cluster
A galaxy cluster, or a cluster of galaxies, is a structure that consists of anywhere from hundreds to thousands of galaxies that are bound together by gravity, with typical masses ranging from 1014 to 1015 solar masses. They are the second-largest known gravitationally bound structures in the universe after galaxy filaments and were believed to be the largest known structures in the universe until the 1980s, when superclusters were discovered. One of the key features of clusters is the intracluster medium (ICM). The ICM consists of heated gas between the galaxies and has a peak temperature between 2–15 keV that is dependent on the total mass of the cluster. Galaxy clusters should not be confused with ''galactic clusters'' (also known as open clusters), which are star clusters ''within'' galaxies, or with globular clusters, which typically orbit galaxies. Small aggregates of galaxies are referred to as galaxy groups rather than clusters of galaxies. The galaxy groups and c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helen B
Helen may refer to: People * Helen of Troy, in Greek mythology, the most beautiful woman in the world * Helen (actress) (born 1938), Indian actress * Helen (given name), a given name (including a list of people with the name) Places * Helen, Georgia, United States, a small city * Helen, Maryland, United States, an unincorporated place * Helen, Washington, an unincorporated community in Washington state, US * Helen, West Virginia, a census-designated place in Raleigh County * Helen Falls, a waterfall in Ontario, Canada * Lake Helen (other), several places called Helen Lake or Lake Helen * Helen, an ancient name of Makronisos island, Greece * The Hellenic Republic, Greece Arts, entertainment, and media * ''Helen'' (album), a 1981 Grammy-nominated album by Helen Humes * ''Helen'' (2008 film), a British drama starring Annie Townsend * ''Helen'' (2009 film), an American drama film starring Ashley Judd * ''Helen'' (2017 film), an Iranian drama film * ''Helen'' (2019 fil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Simons Foundation
The Simons Foundation is a private foundation established in 1994 by Marilyn and Jim Simons with offices in New York City. As one of the largest charitable organizations in the US with assets of over $5 billion in 2022, the foundation's mission is to advance the frontiers of research in mathematics and the basic sciences. The foundation supports science by making grants to individual researchers and their projects. In 2021, Marilyn Simons stepped down as president after 26 years at the helm, and astrophysicist David Spergel was appointed president. The Flatiron Institute In 2016, the foundation launched the Flatiron Institute, its in-house multidisciplinary research institute focused on computational science. The Flatiron Institute hosts centers for computational science in five areas: Funding Areas The foundation makes grants in four program areas: Simons Investigators awardees Among other programs, the Simons Foundation funds the Simons Investigators in MPS program ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PECASE
The Presidential Early Career Award for Scientists and Engineers (PECASE) is the highest honor bestowed by the United States government on outstanding scientists and engineers in the early stages of their independent research careers. The White House, following recommendations from participating agencies, confers the awards annually. To be eligible for a Presidential Award, an individual must be a US citizen, national or permanent resident. Some of the winning scientists and engineers receive up to a five-year research grant. History In February 1996, the National Science and Technology Council (NSTC), was commissioned by President Bill Clinton to create an award program that would honor and support the achievements of young professionals at the outset of their independent research careers in the fields of science and technology. The stated aim of the award is to help maintain the leadership position of the United States in science. Originally, 60 recipients received the PEC ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nancy Grace Roman Space Telescope
The Nancy Grace Roman Space Telescope (shortened as Roman or the Roman Space Telescope, and formerly the Wide-Field Infrared Survey Telescope or WFIRST) is a NASA infrared space telescope currently in development and scheduled to launch by May 2027. Roman was recommended in 2010 by the United States National Research Council Astronomy and Astrophysics Decadal Survey, Decadal Survey committee as the top priority for the next decade of astronomy. On 17 February 2016, WFIRST was approved for development and launch. The Roman Space Telescope is based on an existing wide field of view primary mirror and will carry two scientific instruments. The Wide-Field Instrument (WFI) is a 300.8-megapixel multi-band visible and Infrared, near-infrared camera, providing a sharpness of images comparable to that achieved by the Hubble Space Telescope over a 0.28 square degree field of view, 100 times larger than imaging cameras on the Hubble. The coronagraph, Coronagraphic Instrument (CGI) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scalar Field
In mathematics and physics, a scalar field is a function (mathematics), function associating a single number to every point (geometry), point in a space (mathematics), space – possibly physical space. The scalar may either be a pure Scalar (mathematics), mathematical number (dimensionless) or a scalar (physics), scalar physical quantity (with unit of measurement, units). In a physical context, scalar fields are required to be independent of the choice of reference frame, meaning that any two observers using the same units will agree on the value of the scalar field at the same absolute point in space (or spacetime) regardless of their respective points of origin. Examples used in physics include the temperature distribution throughout space, the pressure distribution in a fluid, and spin-zero quantum fields, such as the Higgs field. These fields are the subject of scalar field theory. Definition Mathematically, a scalar field on a Region (mathematical analysis), region ''U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
General Relativity
General relativity, also known as the general theory of relativity and Einstein's theory of gravity, is the geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of gravitation in modern physics. General relativity generalizes special relativity and refines Newton's law of universal gravitation, providing a unified description of gravity as a geometric property of space and time or four-dimensional spacetime. In particular, the ' is directly related to the energy and momentum of whatever matter and radiation are present. The relation is specified by the Einstein field equations, a system of second order partial differential equations. Newton's law of universal gravitation, which describes classical gravity, can be seen as a prediction of general relativity for the almost flat spacetime geometry around stationary mass distributions. Some predictions of general relativity, however, are beyond Newton's law of universal gravitat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Recombination (cosmology)
In cosmology, recombination refers to the epoch during which charged electrons and protons first became bound to form electrically neutral hydrogen atoms. Recombination occurred about 370,000 yearsRecombination time frames: * Edward L. Wright'Javascript Cosmology Calculator(last modified 23 July 2018). With a default H_0 = (based on ), the calculated age of the universe with a redshift of ''z'' = is in agreement with Olive and Peacock (about 370,000 years). * : "Going forward in time now, the temperature declined, and at ''T''∼3000 K, few of the photons in the radiation field, even in its high-energy tail, had the energy required to ionize a hydrogen atom. Most of the electrons and protons then recombined. Once this happened, at a time ''t''rec = 380,000 yr after the Big Bang, the major source of opacity disappeared, and the Universe became transparent to radiation of most frequencies." * : "The million dollar question is now, 'when did recombination happen? ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dark Matter
Dark matter is a hypothetical form of matter thought to account for approximately 85% of the matter in the universe. Dark matter is called "dark" because it does not appear to interact with the electromagnetic field, which means it does not absorb, reflect, or emit electromagnetic radiation and is, therefore, difficult to detect. Various astrophysical observationsincluding gravitational effects which cannot be explained by currently accepted theories of gravity unless more matter is present than can be seenimply dark matter's presence. For this reason, most experts think that dark matter is abundant in the universe and has had a strong influence on its structure and evolution. The primary evidence for dark matter comes from calculations showing that many galaxies would behave quite differently if they did not contain a large amount of unseen matter. Some galaxies would not have formed at all and others would not move as they currently do. Other lines of evidence include observa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baryonic Matter
In particle physics, a baryon is a type of composite subatomic particle which contains an odd number of valence quarks (at least 3). Baryons belong to the hadron family of particles; hadrons are composed of quarks. Baryons are also classified as fermions because they have half-integer spin. The name "baryon", introduced by Abraham Pais, comes from the Greek word for "heavy" (βαρύς, ''barýs''), because, at the time of their naming, most known elementary particles had lower masses than the baryons. Each baryon has a corresponding antiparticle (antibaryon) where their corresponding antiquarks replace quarks. For example, a proton is made of two up quarks and one down quark; and its corresponding antiparticle, the antiproton, is made of two up antiquarks and one down antiquark. Because they are composed of quarks, baryons participate in the strong interaction, which is mediated by particles known as gluons. The most familiar baryons are protons and neutrons, both of which co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cosmological Perturbation Theory
In physical cosmology, cosmological perturbation theory is the theory by which the ''evolution of structure'' is understood in the Big Bang model. It uses general relativity to compute the gravitational forces causing small perturbations to grow and eventually seed the formation of stars, quasars, galaxies and clusters. It only applies to situations in which the universe is predominantly homogeneous, such as during cosmic inflation and large parts of the Big Bang. The universe is believed to still be homogeneous enough that the theory is a good approximation on the largest scales, but on smaller scales more involved techniques, such as N-body simulations, must be used. Because of the gauge invariance of general relativity, the correct formulation of cosmological perturbation theory is subtle. In particular, when describing an inhomogeneous spacetime there is often not a preferred coordinate choice. There are currently two distinct approaches to perturbation theory in classical gener ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
