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Roger D. Blandford
Roger David Blandford, FRS, FRAS (born 1949) is a British theoretical astrophysicist, best known for his work on black holes. Early life Blandford was born in Grantham, England and grew up in Birmingham. Career Blandford is famous in the astrophysical community for the Blandford-Znajek process which is a mechanism for powering relativistic jets by the extraction of rotational energy from a black hole. The Blandford-Znajek mechanism has been invoked by the Event Horizon Telescope Collaboration to explain the jet power in the first observation of a black hole shadow in the giant elliptical galaxy M87. Blandford also theorized another mechanism for jet formation through hydromagnetic winds launched from accretion disks. In addition to the Blandford-Znajek and Blandford-Payne mechanisms for the formation of relativistic jets, Roger Blandford also helped devise a widely used theoretical model for jet geometric and spectral properties, the Blandford-Königl conical jet model, used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grantham
Grantham () is a market and industrial town in the South Kesteven district of Lincolnshire, England, situated on the banks of the River Witham and bounded to the west by the A1 road. It lies some 23 miles (37 km) south of the Lincoln and 22 miles (35 km) east of Nottingham. The population in 2016 was put at 44,580. The town is the largest settlement and the administrative centre of South Kesteven District. Grantham was the birthplace of the UK Prime Minister Margaret Thatcher. Isaac Newton was educated at the King's School. The town was the workplace of the UK's first warranted female police officer, Edith Smith in 1914. The UK's first running diesel engine was made there in 1892 and the first tractor in 1896. Thomas Paine worked there as an excise officer in the 1760s. The villages of Manthorpe, Great Gonerby, Barrowby, Londonthorpe and Harlaxton form outlying suburbs of the town. Etymology Grantham's name is first attested in the Domesday Book (1086); its orig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Society
The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, recognising excellence in science, supporting outstanding science, providing scientific advice for policy, education and public engagement and fostering international and global co-operation. Founded on 28 November 1660, it was granted a royal charter by King Charles II as The Royal Society and is the oldest continuously existing scientific academy in the world. The society is governed by its Council, which is chaired by the Society's President, according to a set of statutes and standing orders. The members of Council and the President are elected from and by its Fellows, the basic members of the society, who are themselves elected by existing Fellows. , there are about 1,700 fellows, allowed to use the postnominal title FRS (Fellow of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Academies Press
The US National Academies Press (NAP) was created to publish the reports issued by the National Academies of Sciences, Engineering, and Medicine, the National Academy of Engineering, the National Academy of Medicine, and the National Research Council. It publishes nearly 200 books a year on a wide range of topics in the sciences. The NAP's stated mission is seemingly self-contradictory: to disseminate as widely as possible the works of the National Academies of Sciences, Engineering, and Medicine, and to be financially self-sustaining through sales. This mission has led to great experimentation in openness regarding online publishing. The National Academy Press (as it was known in 1993) was the first self-sustaining publisher to make its material available on the Web, for free, in an open access model. By 1997, 1000 reports were available as sequential page images (starting with i, then ii, then iii, then iv...), with a minimal navigational envelope. Their experience up to 1998 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astro2010
The Astronomy and Astrophysics Decadal Survey is a review of astronomy and astrophysics literature produced approximately every ten years by the National Research Council of the National Academy of Sciences in the United States. The report surveys the current state of the field, identifies research priorities, and makes recommendations for the coming decade. The decadal survey represents the recommendations of the research community to governmental agencies on how to prioritize scientific funding within astronomy and astrophysics. The editing committee is informed by topical panels and subcommittees, dedicated conferences, and direct community input in the form of white papers summarizing the state of the art in each subdiscipline. The most recent report, Astro2020, was released in 2021. Ground-Based Astronomy: A Ten-Year Program, 1964 The first report, ''Ground-Based Astronomy: A Ten-Year Program'', was released in 1964. The authoring committee was chaired by Albert Whitford. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
George W
George Walker Bush (born July 6, 1946) is an American politician who served as the 43rd president of the United States from 2001 to 2009. A member of the Republican Party, Bush family, and son of the 41st president George H. W. Bush, he previously served as the 46th governor of Texas from 1995 to 2000. While in his twenties, Bush flew warplanes in the Texas Air National Guard. After graduating from Harvard Business School in 1975, he worked in the oil industry. In 1978, Bush unsuccessfully ran for the House of Representatives. He later co-owned the Texas Rangers of Major League Baseball before he was elected governor of Texas in 1994. As governor, Bush successfully sponsored legislation for tort reform, increased education funding, set higher standards for schools, and reformed the criminal justice system. He also helped make Texas the leading producer of wind powered electricity in the nation. In the 2000 presidential election, Bush defeated Democratic incum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blast Wave
In fluid dynamics, a blast wave is the increased pressure and flow resulting from the deposition of a large amount of energy in a small, very localised volume. The flow field can be approximated as a lead shock wave, followed by a self-similar subsonic flow field. In simpler terms, a blast wave is an area of pressure expanding supersonically outward from an explosive core. It has a leading shock front of compressed gases. The blast wave is followed by a blast wind of Pressure#Negative pressures, negative gauge pressure, which sucks items back in towards the center. The blast wave is harmful especially when one is very close to the center or at a location of constructive interference. High explosives that detonation, detonate generate blast waves. Sources High-order explosives (HE) are more powerful than low-order explosives (LE). HE Detonation, detonate to produce a defining supersonic over-pressurization shock wave. Several sources of HE include trinitrotoluene, C-4 (explosive), C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Messier 87
Messier 87 (also known as Virgo A or NGC 4486, generally abbreviated to M87) is a supergiant elliptical galaxy with several trillion stars in the constellation Virgo. One of the largest and most massive galaxies in the local universe, it has a large population of globular clusters — about 15,000 compared with the 150–200 orbiting the Milky Way — and a jet of energetic plasma that originates at the core and extends at least , traveling at a relativistic speed. It is one of the brightest radio sources in the sky and a popular target for both amateur and professional astronomers. The French astronomer Charles Messier discovered M87 in 1781, and cataloged it as a nebula. M87 is about from Earth and is the second-brightest galaxy within the northern Virgo Cluster, having many satellite galaxies. Unlike a disk-shaped spiral galaxy, M87 has no distinctive dust lanes. Instead, it has an almost featureless, ellipsoidal shape typical of most giant elliptical gala ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elliptical Galaxy
An elliptical galaxy is a type of galaxy with an approximately ellipsoidal shape and a smooth, nearly featureless image. They are one of the four main classes of galaxy described by Edwin Hubble in his Hubble sequence and 1936 work ''The Realm of the Nebulae'', with their intermediate scale disks, a subset of the "early-type" galaxy population. Most elliptical galaxies are composed of older, low-mass stars, with a sparse interstellar medium and minimal star formation activity, and they tend to be surrounded by large numbers of globular clusters. Elliptical galaxies are believed to make up approximately 10–15% of galaxies in the Virgo Supercluster, and they are not the dominant type of galaxy in the universe overall. They are preferentially found close to the centers of galaxy clusters. Elliptical galaxies range in size from dwarf ellipticals with tens of millions of stars, to supergiants of over one hundred trillion stars that dominate their galaxy clusters. Original ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Event Horizon Telescope
The Event Horizon Telescope (EHT) is a large telescope array consisting of a global network of radio telescopes. The EHT project combines data from several very-long-baseline interferometry (VLBI) stations around Earth, which form a combined array with an angular resolution sufficient to observe objects the size of a supermassive black hole's event horizon. The project's observational targets include the two black holes with the largest angular diameter as observed from Earth: the black hole at the center of the supergiant elliptical galaxy Messier 87 (M87*, pronounced "M87-Star"), and Sagittarius A* (Sgr A*, pronounced "Sagittarius A-Star") at the center of the Milky Way. The Event Horizon Telescope project is an international collaboration that was launched in 2009 after a long period of theoretical and technical developments. On the theory side, work on the photon orbit and first simulations of what a black hole would look like progressed to predictions of VLBI imaging for the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Relativistic Jets
An astrophysical jet is an astronomical phenomenon where outflows of ionised matter are emitted as an extended beam along the axis of rotation. When this greatly accelerated matter in the beam approaches the speed of light, astrophysical jets become relativistic jets as they show effects from special relativity. The formation and powering of astrophysical jets are highly complex phenomena that are associated with many types of high-energy astronomical sources. They likely arise from dynamic interactions within accretion disks, whose active processes are commonly connected with compact central objects such as black holes, neutron stars or pulsars. One explanation is that tangled magnetic fields are organised to aim two diametrically opposing beams away from the central source by angles only several degrees wide Jets may also be influenced by a general relativity effect known as frame-dragging. Most of the largest and most active jets are created by supermassive black holes (SMBH) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Birmingham
Birmingham ( ) is a city and metropolitan borough in the metropolitan county of West Midlands in England. It is the second-largest city in the United Kingdom with a population of 1.145 million in the city proper, 2.92 million in the West Midlands metropolitan county, and approximately 4.3 million in the wider metropolitan area. It is the largest UK metropolitan area outside of London. Birmingham is known as the second city of the United Kingdom. Located in the West Midlands region of England, approximately from London, Birmingham is considered to be the social, cultural, financial and commercial centre of the Midlands. Distinctively, Birmingham only has small rivers flowing through it, mainly the River Tame and its tributaries River Rea and River Cole – one of the closest main rivers is the Severn, approximately west of the city centre. Historically a market town in Warwickshire in the medieval period, Birmingham grew during the 18th century during the Midla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
