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Cosmic Background Radiation
Cosmic background radiation is electromagnetic radiation that fills all space. The origin of this radiation depends on the region of the spectrum that is observed. One component is the cosmic microwave background. This component is redshifted photons that have freely streamed from an epoch when the Universe became transparent for the first time to radiation. Its discovery and detailed observations of its properties are considered one of the major confirmations of the Big Bang. Background radiation is largely homogeneous and isotropic. A slight detectable anisotropy is present which correlates to galaxy filaments and voids. The discovery (by chance in 1965) of the cosmic background radiation suggests that the early universe was dominated by a radiation field, a field of extremely high temperature and pressure. There is background radiation observed across all wavelength regimes, peaking in microwave, but also notable in infrared and X-ray regimes. Fluctuations in cosmic backgr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extragalactic Background Light
The diffuse extragalactic background light (EBL) is all the accumulated radiation in the universe due to star formation processes, plus a contribution from active galactic nuclei (AGNs). This radiation covers almost all wavelengths of the electromagnetic spectrum, except the microwave, which is dominated by the primordial cosmic microwave background. The EBL is part of the diffuse extragalactic background radiation (DEBRA), which by definition covers the entire electromagnetic spectrum. After the cosmic microwave background, the EBL produces the second-most energetic diffuse background, thus being essential for understanding the full energy balance of the universe. The understanding of the EBL is also fundamental for extragalactic very-high-energy (VHE, 30 GeV-30 TeV) astronomy. VHE photons coming from cosmological distances are attenuated by pair production with EBL photons. This interaction is dependent on the spectral energy distribution (SED) of the EBL. Therefore, it is nece ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Robert Herman
Robert Herman (August 29, 1914 – February 13, 1997) was an American astronomer, best known for his work with Ralph Alpher in 1948–50, on estimating the temperature of cosmic microwave background radiation from the Big Bang explosion. Biography and career Born in the Bronx, New York City, Herman graduated cum laude with special honors in physics from the City College of New York in 1935, and in 1940 was awarded master's and doctoral degrees in physics from Princeton University in the area of molecular spectroscopy. As a graduate student, Herman already exhibited eclectic tendencies in diverse fields by also working in solid state physics, as well as straddling theory and experiment. He spent the academic year 1940-41 working on the Bush differential analyzer at the Moore School of Electrical Engineering, University of Pennsylvania, and another year teaching physics at the City College of New York. In 1942, he left teaching to work at the Department of Terrestrial Magnetism ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ralph Alpher
Ralph Asher Alpher (February 3, 1921 – August 12, 2007) was an American cosmologist, who carried out pioneering work in the early 1950s on the Big Bang model, including Big Bang nucleosynthesis and predictions of the cosmic microwave background radiation. Childhood and education Alpher was the son of a Jewish immigrant, Samuel Alpher ( Ilfirovich), from Vitebsk, Russian Empire. His mother, Rose Maleson, died of stomach cancer in 1938, and his father later remarried. Alpher graduated at age 15 from Theodore Roosevelt High School in Washington, D.C., and held the ranks of Major and Commander of his school's Cadet program. He worked in the high school theater as stage manager for two years, supplementing his family's Depression-era income. He also learned Gregg shorthand, and in 1937 began working for the director of the American Geophysical Union as a stenographer. In 1940, he was hired by the Department of Terrestrial Magnetism of the Carnegie Foundation, where he worked ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
George Gamow
George Gamow (sometimes Gammoff; born Georgiy Antonovich Gamov; ; 4 March 1904 – 19 August 1968) was a Soviet and American polymath, theoretical physicist and cosmologist. He was an early advocate and developer of Georges Lemaître's Big Bang theory. Gamow discovered a theoretical explanation of alpha decay by quantum tunneling, invented the liquid drop model (the first mathematical model of the atomic nucleus), worked on radioactive decay, star formation, stellar nucleosynthesis, Big Bang nucleosynthesis (which he collectively called nucleocosmogenesis), and predicted the existence of the cosmic microwave background radiation and molecular genetics. Gamow was a key figure in the development and understanding of quantum tunneling. In his middle and late career, Gamow directed much of his attention to teaching and wrote popular books on science, including '' One Two Three... Infinity'' and the '' Mr Tompkins'' series of books (1939–1967). Some of his books remain in print ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Robert Beringer
The name Robert is an ancient Germanic given name, from Proto-Germanic "fame" and "bright" (''Hrōþiberhtaz''). Compare Old Dutch ''Robrecht'' and Old High German ''Hrodebert'' (a compound of '' Hruod'' () "fame, glory, honour, praise, renown, godlike" and ''berht'' "bright, light, shining"). It is the second most frequently used given name of ancient Germanic origin.Reaney & Wilson, 1997. ''Dictionary of English Surnames''. Oxford University Press. It is also in use as a surname. Another commonly used form of the name is Rupert. After becoming widely used in Continental Europe, the name entered England in its Old French form ''Robert'', where an Old English cognate form (''Hrēodbēorht'', ''Hrodberht'', ''Hrēodbēorð'', ''Hrœdbœrð'', ''Hrœdberð'', ''Hrōðberχtŕ'') had existed before the Norman Conquest. The feminine version is Roberta. The Italian, Portuguese, and Spanish form is Roberto. Robert is also a common name in many Germanic languages, including Eng ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Robert Dicke
Robert Henry Dicke (; May 6, 1916 – March 4, 1997) was an American astronomer and physicist who made important contributions to the fields of astrophysics, atomic physics, cosmology and gravity. He was the Albert Einstein Professor in Science at Princeton University (1975–1984). Biography Born in St. Louis, Missouri, Dicke completed his bachelor's degree at Princeton University and his doctorate, in 1939, from the University of Rochester in nuclear physics. During the Second World War he worked in the Radiation Laboratory at the Massachusetts Institute of Technology where he worked on the development of radar and designed the Dicke radiometer, a microwave receiver. He used this to set a limit on the temperature of the microwave background radiation, from the roof of the Radiation Laboratory, of less than 20 kelvins. In 1946, he returned to Princeton University, where he remained for the remainder of his career. He did some work in atomic physics, particularly on the l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Walther Nernst
Walther Hermann Nernst (; 25 June 1864 – 18 November 1941) was a German physical chemist known for his work in thermodynamics, physical chemistry, electrochemistry, and solid-state physics. His formulation of the Nernst heat theorem helped pave the way for the third law of thermodynamics, for which he won the 1920 Nobel Prize in Chemistry. He is also known for developing the Nernst equation in 1887. He studied physics and mathematics at the universities of Zürich, Berlin, Graz and Würzburg, where he received his doctorate 1887. In 1889, he finished his habilitation at University of Leipzig. Life and career Early years Nernst was born in Briesen, Germany (now Wąbrzeźno, Poland) to Gustav Nernst (1827–1888) and Ottilie Nerger (1833–1876). His father was a country judge. Nernst had three older sisters and one younger brother. His third sister died of cholera. Nernst went to elementary school at Graudenz, Germany (now Grudziądz, Poland). Studies Nernst started ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erich Regener
Erich Rudolf Alexander Regener (12 November 1881 – 27 February 1955) was a German physicist known primarily for the design and construction of instruments to measure cosmic ray intensity at various altitudes. He is also known for predicting a Cosmic microwave background, for the invention of the scintillation counter which contributed to the discovery of the structure of the atom, for his calculation of the charge of an electron and for his early work on atmospheric ozone. He is also credited with the first use of rockets for scientific research. Regener was born in Schleusenau (Wilczak) near Bromberg (Bydgoszcz), West Prussia. He studied physics from 1900 to 1905 at the University of Berlin under Emil Warburg and from 1909 worked with Heinrich Rubens. In 1911 he became professor of experimental physics and meteorology at the Agricultural University of Berlin. In 1920 he became the professor in experimental physics at the University of Stuttgart working alongside the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Starlight
Starlight is the light emitted by stars. It typically refers to visible electromagnetic radiation from stars other than the Sun, observable from Earth at night, although a component of starlight is observable from Earth during daytime. Sunlight is the term used for the Sun's starlight observed during daytime. During nighttime, albedo describes solar reflections from other Solar System objects, including moonlight, planetshine, and zodiacal light. Observation Observation and measurement of starlight through telescopes is the basis for many fields of astronomy, including photometry and stellar spectroscopy. Hipparchus did not have a telescope or any instrument that could measure apparent brightness accurately, so he simply made estimates with his eyes. He sorted the stars into six brightness categories, which he called magnitudes.''Astronomy''. https://d3bxy9euw4e147.cloudfront.net/oscms-prodcms/media/documents/Astronomy-Draft-20160817.pdf: Rice University. 2016. p. 761. - v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthur Eddington
Sir Arthur Stanley Eddington, (28 December 1882 – 22 November 1944) was an English astronomer, physicist, and mathematician. He was also a philosopher of science and a populariser of science. The Eddington limit, the natural limit to the luminosity of stars, or the radiation generated by accretion onto a compact object, is named in his honour. Around 1920, he foreshadowed the discovery and mechanism of nuclear fusion processes in stars, in his paper "The Internal Constitution of the Stars".The Internal Constitution of the Stars A. S. Eddington The Scientific Monthly Vol. 11, No. 4 (Oct., 1920), pp. 297–303 At that time, the source of stellar energy was a complete mystery; Eddington was the first to correctly speculate that the source was fusion of hydrogen into helium. Eddington wrote a number of articles that announced and explained Einstein's theory of general relativity to the English-speaking world. World War I had severed many lines of scientific communication, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kelvin
The kelvin (symbol: K) is the base unit for temperature in the International System of Units (SI). The Kelvin scale is an absolute temperature scale that starts at the lowest possible temperature (absolute zero), taken to be 0 K. By definition, the Celsius scale (symbol °C) and the Kelvin scale have the exact same magnitude; that is, a rise of 1 K is equal to a rise of 1 °C and vice versa, and any temperature in degrees Celsius can be converted to kelvin by adding 273.15. The 19th century British scientist Lord Kelvin first developed and proposed the scale. It was often called the "absolute Celsius" scale in the early 20th century. The kelvin was formally added to the International System of Units in 1954, defining 273.16 K to be the triple point of water. The Celsius, Fahrenheit, and Rankine scales were redefined in terms of the Kelvin scale using this definition. The 2019 revision of the SI now defines the kelvin in terms of energy by setting the Bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
