George Gamow (March 4, 1904 – August 19, 1968), born Georgiy Antonovich Gamov, was a Soviet-American theoretical physicist and cosmologist. He was an early advocate and developer of Lemaître's Big Bang theory. He discovered a theoretical explanation of alpha decay via quantum tunneling, and worked on radioactive decay of the atomic nucleus, star formation, stellar nucleosynthesis and Big Bang nucleosynthesis (which he collectively called nucleocosmogenesis), and molecular genetics.
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 are still in print more than a half-century after their original publication.
Georgiy Antonovich Gamov
March 4, 1904 (O.S. February 20, 1904)
|Died||August 19, 1968 (aged 64)|
Boulder, Colorado, United States
|Citizenship||Soviet Union, |
|Alma mater||Leningrad State University|
|Known for||Gamow factor|
Liquid drop model
One Two Three ... Infinity
|Awards||Kalinga Prize (1956)|
|Fields||Physicist, science writer|
|Institutions||University of Göttingen|
Niels Bohr Institute
George Washington University
University of California, Berkeley
University of Colorado Boulder
|Doctoral advisor||Alexander Friedmann|
|Doctoral students||Ralph Asher Alpher|
Gamow was born in Odessa, Russian Empire. His father taught Russian language and literature in high school, and his mother taught geography and history at a school for girls. In addition to Russian, Gamow learned to speak some French from his mother and German from a tutor. Gamow learned fluent English in his college years and later. Most of his early publications were in German or Russian, but he later switched to writing in English for both technical papers and for the lay audience.
He was educated at the Institute of Physics and Mathematics in Odessa (1922–23) and at the University of Leningrad (1923–1929). Gamow studied under Alexander Friedmann for some time in Leningrad, until Friedmann's early death in 1925. He aspired to do his doctoral thesis under Friedmann, but had to change dissertation advisors. At the University, Gamow made friends with three other students of theoretical physics, Lev Landau, Dmitri Ivanenko, and Matvey Bronshtein. The four formed a group known as the Three Musketeers, which met to discuss and analyze the ground-breaking papers on quantum mechanics published during those years. He later used the same phrase to describe the Alpher, Herman, and Gamow group.
On graduation, he worked on quantum theory in Göttingen, where his research into the atomic nucleus provided the basis for his doctorate. He then worked at the Theoretical Physics Institute of the University of Copenhagen from 1928 to 1931, with a break to work with Ernest Rutherford at the Cavendish Laboratory in Cambridge. He continued to study the atomic nucleus (proposing the "liquid drop" model), but also worked on stellar physics with Robert Atkinson and Fritz Houtermans.
In 1931, Gamow was elected a corresponding member of the Academy of Sciences of the USSR at age 28 – one of the youngest in the history of this organization. During the period 1931–1933, Gamow worked in the Physical Department of the Radium Institute (Leningrad) headed by Vitaly Khlopin. Europe's first cyclotron was designed under the guidance and direct participation of Igor Kurchatov, Lev Mysovskii and Gamow. In 1932, Gamow and Mysovskii submitted a draft design for consideration by the Academic Council of the Radium Institute, which approved it. The cyclotron was not completed until 1937.
In the early 20th century, radioactive materials were known to have characteristic exponential decay rates, or half-lives. At the same time, radiation emissions were known to have certain characteristic energies. By 1928, Gamow in Göttingen had solved the theory of the alpha decay of a nucleus via tunnelling, with mathematical help from Nikolai Kochin. The problem was also solved independently by Ronald W. Gurney and Edward U. Condon. Gurney and Condon did not, however, achieve the quantitative results achieved by Gamow.
Classically, the particle is confined to the nucleus because of the high energy requirement to escape the very strong nuclear potential well. Also classically, it takes an enormous amount of energy to pull apart the nucleus, an event that would not occur spontaneously. In quantum mechanics, however, there is a probability the particle can "tunnel through" the wall of the potential well and escape. Gamow solved a model potential for the nucleus and derived from first principles a relationship between the half-life of the alpha-decay event process and the energy of the emission, which had been previously discovered empirically and was known as the Geiger–Nuttall law. Some years later, the name Gamow factor or Gamow–Sommerfeld factor was applied to the probability of incoming nuclear particles tunnelling through the electrostatic Coulomb barrier and undergoing nuclear reactions.
Gamow worked at a number of Soviet establishments before deciding to flee the Soviet Union because of increased oppression. In 1931, he was officially denied permission to attend a scientific conference in Italy. Also in 1931, he married Lyubov Vokhmintseva (Russian: Любовь Вохминцева), another physicist in Soviet Union, whom he nicknamed "Rho" after the Greek letter. Gamow and his new wife spent much of the next two years trying to leave the Soviet Union, with or without official permission. Niels Bohr and other friends invited Gamow to visit during this period, but Gamow could not get permission to leave.
Gamow later said that his first two attempts to defect with his wife were in 1932 and involved trying to kayak: first a planned 250-kilometer paddle over the Black Sea to Turkey, and another attempt from Murmansk to Norway. Poor weather foiled both attempts, but they had not been noticed by the authorities.
In 1933, Gamow was suddenly granted permission to attend the 7th Solvay Conference on physics, in Brussels. He insisted on having his wife accompany him, even saying that he would not go alone. Eventually the Soviet authorities relented and issued passports for the couple. The two attended and arranged to extend their stay, with the help of Marie Curie and other physicists. Over the next year, Gamow obtained temporary work at the Curie Institute, University of London, and the University of Michigan.
In 1934, Gamow and his wife moved to the United States. He became a professor at George Washington University (GWU) in 1934 and recruited physicist Edward Teller from London to join him at GWU. In 1936, Gamow and Teller published what became known as the "Gamow–Teller selection rule" for beta decay. During his time in Washington, Gamow would also publish major scientific papers with Mário Schenberg and Ralph Alpher. By the late 1930s, Gamow's interests had turned towards astrophysics and cosmology.
In 1935, Gamow's son, Igor Gamow was born (in his 1947 book, Gamow's dedication was "To my son Igor, who wanted to be a cowboy"). George Gamow became a naturalized American in 1940. He retained his formal association with GWU until 1956.
During World War II, Gamow did not work directly on the Manhattan Project producing the atomic bomb, in spite of his knowledge of radioactivity and nuclear fusion. He continued to teach physics at GWU and consulted for the U.S. Navy.
Gamow was interested in the processes of stellar evolution and the early history of the Solar System. In 1945, he co-authored a paper supporting work by German theoretical physicist Carl Friedrich von Weizsäcker on planetary formation in the early Solar System. Gamow published another paper in the British journal Nature in 1948, in which he developed equations for the mass and radius of a primordial galaxy (which typically contains about one hundred billion stars, each with a mass comparable with that of the Sun).
Gamow's work led the development of the hot "big bang" theory of the expanding universe. He was the earliest to employ Alexander Friedmann's and Georges Lemaître's non-static solutions of Einstein's gravitational equations describing a universe of uniform matter density and constant spatial curvature. Gamow's crucial advance would provide a physical reification of Lemaître's idea of a unique primordial quantum. Gamow did this by assuming that the early universe was dominated by radiation rather than by matter. Most of the later work in cosmology is founded in Gamow's theory. He applied his model to the question of the creation of the chemical elements  and to the subsequent condensation of matter into galaxies, whose mass and diameter he was able to calculate in terms of the fundamental physical parameters, such as the speed of light c, Newton's gravitational constant G, Sommerfeld's fine-structure constant α, and Planck's constant h.
Gamow's interest in cosmology arose from his earlier interest in energy generation and element production and transformation in stars. This work, in turn, evolved from his fundamental discovery of quantum tunneling as the mechanism of nuclear alpha decay, and his application of this theory to the inverse process to calculate rates of thermonuclear reaction.
At first, Gamow believed that all the elements might be produced in the very high temperature and density early stage of the universe. Later, he revised this opinion on the strength of compelling evidence advanced by Fred Hoyle et al. that elements heavier than lithium are largely produced in thermonuclear reactions in stars and in supernovae. Gamow formulated a set of coupled differential equations describing his proposed process and assigned, as a PhD. dissertation topic, his graduate student Ralph Alpher the task of solving the equations numerically. These results of Gamow and Alpher appeared in 1948 as the Alpher–Bethe–Gamow paper. Bethe later referred to this paper as being "wrong". Before his interest turned to the question of the genetic code, Gamow published about twenty papers on cosmology. The earliest was in 1939 with Edward Teller on galaxy formation, followed in 1946 by the first description of cosmic nucleosynthesis. He also wrote many popular articles as well as academic textbooks on this and other subjects.
In 1948, he published a paper dealing with an attenuated version of the coupled set of equations describing the production of the proton and the deuteron from thermal neutrons. By means of a simplification and using the observed ratio of hydrogen to heavier elements he was able to obtain the density of matter at the onset of nucleosynthesis and from this the mass and diameter of the early galaxies. In 1953 he produced similar results, but this time based on another determination of the density of matter and radiation at the point at which they became equal. In this paper Gamow determined the density of the relict background radiation from which a present temperature of 7K is trivially predicted – a value slightly more than twice the presently accepted value. In 1967 he published a reminder and recapitulation of his own work as well as that of Alpher and Robert Herman (both with Gamow and also independently of him). This was prompted by the discovery of the cosmic background radiation by Penzias and Wilson in 1965, for which Gamow, Alpher and Herman felt that they did not receive the credit they deserved for their prediction of its existence and source. Gamow was disconcerted by the fact that the authors of a communication explaining the significance of the Penzias/Wilson observations failed to recognize and cite the previous work of Gamow and his collaborators.
In 1953, Francis Crick, James Watson, Maurice Wilkins and Rosalind Franklin discovered the double helix structure of the DNA macromolecule. Gamow attempted to solve the problem of how the ordering of four different bases (adenine, cytosine, thymine and guanine) in DNA chains might control the synthesis of proteins from their constituent amino acids. Crick has said that Gamow's suggestions helped him in his own thinking about the problem. As related by Crick, Gamow observed that the 43 = 64 possible permutations of the four DNA bases, taken three at a time, would be reduced to 20 distinct combinations if the order was irrelevant.. Gamow proposed that these 20 combinations might code for the twenty amino acids which, he suggested, might well be the sole constituents of all proteins. Gamow's contribution to solving the problem of genetic coding gave rise to important models of biological degeneracy.
The specific system that Gamow was proposing (called "Gamow's diamonds") proved to be incorrect. The triplets were supposed to be overlapping, so that in the sequence GGAC (for example), GGA could produce one amino acid and GAC another, and also non-degenerate (meaning that each amino acid would correspond to one combination of three bases – in any order). Later protein sequencing work proved that this could not be the case; the true genetic code is non-overlapping and degenerate, and changing the order of a combination of bases does change the amino acid.
In 1954, Gamow and Watson co-founded the RNA Tie Club. This was a discussion group of leading scientists concerned with the problem of the genetic code, which counted among its members the physicists Edward Teller and Richard Feynman. In his autobiographical writings, Watson later acknowledged the great importance of Gamow's insightful initiative. However, this did not prevent him from describing this colorful personality as a "zany", card-trick playing, limerick-singing, booze-swilling, practical–joking "giant imp".
Gamow worked at George Washington University from 1934 until 1954, when he became a visiting professor at the University of California, Berkeley. In 1956, he moved to the University of Colorado Boulder, where he remained for the rest of his career. In 1956, Gamow became one of the founding members of the Physical Science Study Committee (PSSC), which later reformed teaching of high-school physics in the post-Sputnik years. Also in 1956, he divorced his first wife. Gamow later married Barbara Perkins (an editor for one of his publishers) in 1958.
In 1959, Gamow, Hans Bethe, and Victor Weisskopf publicly supported the re-entry of Frank Oppenheimer into teaching college physics at the University of Colorado, as the Red Scare began to fade (J. Robert Oppenheimer was the older brother of Frank Oppenheimer, and both of them had worked on the Manhattan Project before their careers in physics were derailed by McCarthyism).:130 While in Colorado, Frank Oppenheimer became increasingly interested in teaching science through simple hands-on experiments, and he eventually moved to San Francisco to found the Exploratorium.:130–152 Gamow would not live to see his colleague's opening of this innovative new science museum, in late August 1969.:152
In his 1961 book The Atom and its Nucleus, Gamow proposed representing the periodic system of the chemical elements as a continuous tape, with the elements in order of atomic number wound round in a three-dimensional helix whose diameter increased stepwise (corresponding to the longer rows of the conventional periodic table).
Gamow continued his teaching at the University of Colorado Boulder and focused increasingly on writing textbooks and books on science for the general public. After several months of ill health, surgeries on his circulatory system, diabetes and liver problems, Gamow was dying from liver failure, which he had called the "weak link" that could not withstand the other stresses.
In a letter written to Ralph Alpher on August 18, he had written, "The pain in the abdomen is unbearable and does not stop". Prior to this, there had been a long exchange of letters with his former student, in which he was seeking a fresh understanding of some concepts used in his earlier work, with Paul Dirac. Gamow relied on Alpher for deeper understanding of mathematics.
On August 19, 1968, Gamow died at age 64 in Boulder, Colorado, and was buried there in Green Mountain Cemetery. The physics department tower at the University of Colorado at Boulder is named for him.
Gamow was a highly successful science writer, with several of his books still in print more than a half-century after their initial publication. As an educator, Gamow recognized and emphasized fundamental principles that were unlikely to become obsolete, even as the pace of science and technology accelerated. He also conveyed a sense of excitement with the revolution in physics and other scientific topics of interest to the common reader. Gamow himself sketched the many illustrations for his books, which added a new dimension to and complemented what he intended to convey in the text. He was unafraid to introduce mathematics wherever it was essential, but he tried to avoid deterring potential readers by including large numbers of equations that did not illustrate essential points.
Before his death, Gamow was working with Richard Blade on a textbook Basic Theories in Modern Physics, but the work was never completed or published under that title. Gamow was also writing My World Line: An Informal Autobiography, which was published posthumously in 1970.
A collection of Gamow's writings was donated to The George Washington University in 1996. The materials include correspondence, articles, manuscripts and printed materials both by and about George Gamow. The collection is currently under the care of GWU's Special Collections Research Center, located in the Estelle and Melvin Gelman Library.
After the initial mathematical work on relativity theory had been done, the Big Bang theory itself was invented by a Belgian priest, Georges Lemaître, improved upon by an avowed atheist, George Gamow, and is now all but universally accepted by those who hold advanced degrees in astronomy and the physical sciences, despite its obvious absurdity.
Surprisingly, the atheist George Gamow enjoyed the Papal attention given to his field of research.
In physical cosmology, the Alpher–Bethe–Gamow paper, or αβγ paper, was created by Ralph Alpher, then a physics PhD student, and his advisor George Gamow. The work, which would become the subject of Alpher's PhD dissertation, argued that the Big Bang would create hydrogen, helium and heavier elements in the correct proportions to explain their abundance in the early universe. While the original theory neglected a number of processes important to the formation of heavy elements, subsequent developments showed that Big Bang nucleosynthesis is consistent with the observed constraints on all primordial elements.
Formally titled "The Origin of Chemical Elements", it was published in the April 1948 issue of Physical Review.Augusta H. Teller
Augusta Maria "Mici" Teller (née Schütz-Harkányi) (30 May 1909 – 4 June 2000) was an American scientist and computer programmer, involved in the development of the Metropolis algorithm.
Born as Auguszta Mária Harkányi, she and her brother, Ede, were adopted by their foster father after their biological father's death, who gave them their second last name. Ede "Szuki" Schütz-Harkányi was a childhood friend of Edward Teller.
In 1932–33, she spent two years at the University of Pittsburgh with a scholarship. When she returned to Hungary, she married her longtime friend, Teller, in February 1934. The Tellers emigrated to the United States in 1935, after Russian-born physicist George Gamow invited Edward to teach at the George Washington University. She and her husband became American citizens on March 6, 1941.
She wrote an initial version of the MANIAC I code for the first paper introducing Markov chain Monte Carlo simulation, though the final code used in the publication was written in entirety by Arianna Rosenbluth.Barbara Perkins Gamow
Barbara Merrihew Perkins "Perky" Gamow (May 22, 1905 - December 1975) was an American publicity manager, editor and translator.CGh physics
cGh physics refers to the mainstream attempts in physics to unify relativity, gravitation and quantum mechanics, in particular following the ideas of Matvei Petrovich Bronstein and George Gamow. The letters are the standard symbols for the speed of light (c), the gravitational constant (G), and Planck's constant (h).
If one considers these three universal constants as the basis for a 3-D coordinate system and envisions a cube, then this pedagogic construction provides a framework, which is referred to as the cGh cube, or physics cube, or cube of theoretical physics (CTP). This cube can used for organizing major subjects within physics as occupying each of the eight corners. The eight corners of the cGh physics cube are:
Classical mechanics (_,_,_)
Special relativity (c,_,_), Gravitation (_,G,_), Quantum mechanics (_,_,h)
General relativity (c,G,_), Quantum field theory (c,_,h), Non-relativistic quantum theory with gravity (_,G,h)
Theory of everything, or relativistic quantum gravity (c,G,h)Other cGh subjects include Planck units, Hawking radiation and black hole thermodynamics.
While there are several other physical constants, these three are given special consideration, because they can be used to define all Planck units and thus all physical quantities. The three constants are therefore used sometimes as a framework for philosophical study and as one of pedagogical patterns.Elevator paradox
The elevator paradox is a paradox first noted by Marvin Stern and George Gamow, physicists who had offices on different floors of a multi-story building. Gamow, who had an office near the bottom of the building noticed that the first elevator to stop at his floor was most often going down, while Stern, who had an office near the top, noticed that the first elevator to stop at his floor was most often going up.At first sight, this created the impression that perhaps elevator cars were being manufactured in the middle of the building and sent upwards to the roof and downwards to the basement to be dismantled. Clearly this was not the case. But how could the observation be explained?Gamov
Gamov or Gamow (Russian: Гамов) is a Russian male surname, its feminine counterpart is Gamova or Gamowa. It may refer to
Dmitry Gamov (1834–1903), Russian explorer
George Gamow (1904–1968), Russian-born physicist and cosmologist
Igor Gamow (born 1936), American inventor, son of George Gamow
Vitaly Gamov (1962–2002), Russian Border Guard Official
Yekaterina Gamova (born 1980), Russian volleyball playerGamow
Gamow may refer to:
Gamów, a village in Poland
Gamow (crater), a large impact crater on the far side of the Moon
GAMOW, an acronym for the Godless Americans March on Washington
George Gamow, theoretical physicist and prize-winning science writerGamow (crater)
Gamow is a large lunar impact crater on the far side of the Moon. It is located in the northern hemisphere, to the southeast of the walled plain Schwarzschild. The crater is named after the Russian-American physicist George Gamow.This is a worn and eroded feature, with a rim that has been battered and overlain by multiple impacts. Gamow V is attached to the western exterior, and the joined crater pair Gamow A and Gamow B overlie the northeastern side. The eastern rim is the most damaged section, while the rim to the west is free from impacts. The western inner wall does display a fine radial groove texture, but is otherwise nearly featureless. Near the midpoint is a palimpsest, or ghost-crater feature consisting of just the rim projecting up through the otherwise relatively level surface.Gamow factor
The Gamow Factor or Gamow-Sommerfeld Factor, named after its discoverer George Gamow, is a probability factor for two nuclear particles' chance of overcoming the Coulomb barrier in order to undergo nuclear reactions, for example in nuclear fusion. By classical physics, there is almost no possibility for protons to fuse by crossing each other's Coulomb barrier, but when George Gamow instead applied quantum mechanics to the problem, he found that there was a significant chance for the fusion due to tunneling.
The probability of two nuclear particles overcoming their electrostatic barriers is given by the following equation:
Where is the Gamow Energy.
Here, is the reduced mass of the two particles. The constant is the fine structure constant, is the speed of light, and and are the respective atomic numbers of each particle.
While the probability of overcoming the Coulomb barrier increases rapidly with increasing particle energy, for a given temperature, the probability of a particle having such an energy falls off very fast, as described by the Maxwell–Boltzmann distribution. Gamow found that, taken together, these effects mean that for any given temperature, the particles that fuse are mostly in a temperature-dependent narrow range of energies known as the Gamow window.Igor Gamow
Rustem Igor Gamow (Georgetown, D.C., November 4, 1935), son of physicist George Gamow, is a former microbiology professor at the University of Colorado and inventor. His best known inventions include the Gamow bag and the Shallow Underwater Breathing Apparatus.
Rustem Igor Gamow was born to George Gamow, the celebrated cosmologist and physicist, and ballet dancer Rho Gamow. Finishing high school at age 17, he joined the National Ballet Company. He held such jobs as breaking horses, delivering packages by motorcycle, and teaching karate before enrolling at the University of Colorado in 1958, where his father taught physics, microbiology and microphysics. Gamow holds a B.A. and M.S. in biology, and a Ph.D. in biophysics, all at University of Colorado.Marjorie Hall Harrison
Marjorie Hall Harrison (September 14, 1918 – August 6, 1986) was an English-born American astronomer.
Hall was born in Nottingham, England in September 1918. In 1947, she authored one of the first scientific books, a dissertation while at the Yerkes Observatory of the University of Chicago, with the word "model" in the title. This work describes the processes that fuel stars and is among the first works that endeavored to create detailed mathematical models for complex physical systems. Along with Subrahmanyan Chandrasekhar, George Gamow and G. Keller, Harrison published models in 1944, 1946 and 1947 discussing stars modeled with hydrogen-depleted and isothermal cores. As a doctoral student of S. Chandrasekhar at the University of Chicago, she received a degree in astronomy in 1947.
A brother, Cecil Hall, was one of Eli Franklin Burton's graduate students who build the first practical electron microscope at the University of Toronto in 1938. Hall Harrison died in Huntsville, Texas in August 1986 at the age of 67.Martynas Yčas
Martynas Yčas was a Lithuanian-born microbiologist. He co-authored the book Mr. Tompkins: Inside Himself with physicist George Gamow. He was a founding member of the RNA Tie Club, a discussion society of scientists who attempted to solve the question of the genetic code and with Gamow and others published early statistical analyses of proteins and DNA which disproved some early models of the genetic code.Mr Tompkins
Mr Tompkins is the title character in a series of four popular science books by the physicist George Gamow. The books are structured as a series of dreams in which Mr Tompkins enters alternative worlds where the physical constants have radically different values from those they have in the real world. Gamow aims to use these alterations to explain modern scientific theories.
Mr Tompkins' adventures begin when he chooses to spend the afternoon of a bank holiday attending a lecture on the theory of relativity. The lecture proves less comprehensible than he had hoped and he drifts off to sleep and enters a dream world in which the speed of light is a mere 4.5 m/s (10 mph). This becomes apparent to him through the fact that passing cyclists are subject to a noticeable Lorentz–FitzGerald contraction. Mr Tompkins becomes acquainted with the Professor delivering the lectures and ultimately marries the Professor's daughter, Maud. Later chapters in the books deal with atomic structure (Mr Tompkins spends time as a conduction electron, returning to consciousness when he is annihilated in an encounter with a positron) and thermodynamics (the Professor expounds an analogy between the second law of thermodynamics and the bias towards the casino in gambling before being confounded by a local reversal of the second law through the intervention of Maxwell's demon who has introduced himself to Maud in one of her dreams). Mr Tompkins' initials are 'C.G.H.' which stand for c (the speed of light), G (the constant of gravitation) and h (Planck's constant). Following their marriage Maud refers to him as 'Cyril'.
Later books in the series tackled biology and advanced cosmology.
In 2010 the first volume of a proposed ten-issue comic book series, The Adventures of Mr. Tompkins, was created by Igor Gamow, George Gamow's son, and illustrator Scorpio Steele. In the book Tompkins learns about relativity from Albert Einstein, radioactivity from Marie Curie and the structure of the atom from Ernest Rutherford. A second volume, in which Tompkins meets Charles Darwin, Gregor Mendel and James Watson, was published in July 2011.
Main belt asteroid 12448 Mr. Tompkins is named after Tompkins.The Scientific Background to the 2017 Nobel Prize in Chemistry begins by citing Mr Tomkins inside himselfOne Two Three... Infinity
One Two Three... Infinity: Facts and Speculations of Science is a popular science book by theoretical physicist George Gamow, first published in 1947, exploring some fundamental concepts in mathematics and science, but written at a level understandable by middle school students up through "intelligent layman" adults. The book is illustrated by Gamow.The Birth and Death of the Sun
The Birth and Death of the Sun is a popular science book by theoretical physicist and cosmologist George Gamow, first published in 1940, exploring atomic chemistry, stellar evolution, and cosmology. The book is illustrated by Gamow. It was revised in 1952.Timeline of stellar astronomy
Timeline of stellar astronomy
2300 BC — First great period of star naming in China.
134 BC — Hipparchus creates the magnitude scale of stellar apparent luminosities
185 AD — Chinese astronomers become the first to observe a supernova, the SN 185
964 — Abd al-Rahman al-Sufi (Azophi) writes the Book of Fixed Stars, in which he makes the first recorded observations of the Andromeda Galaxy and the Large Magellanic Cloud, and lists numerous stars with their positions, magnitudes, brightness, and colour, and gives drawings for each constellation
1000s (decade) — The Persian astronomer, Abū Rayhān al-Bīrūnī, describes the Milky Way galaxy as a collection of numerous nebulous stars
1006 — Ali ibn Ridwan and Chinese astronomers observe the SN 1006, the brightest stellar event ever recorded
1054 — Chinese and Arab astronomers observe the SN 1054, responsible for the creation of the Crab Nebula, the only nebula whose creation was observed
1181 — Chinese astronomers observe the SN 1181 supernova
1580 — Taqi al-Din measures the right ascension of the stars at the Constantinople Observatory of Taqi ad-Din using an "observational clock" he invented and which he described as "a mechanical clock with three dials which show the hours, the minutes, and the seconds"
1596 — David Fabricius notices that Mira's brightness varies
1672 — Geminiano Montanari notices that Algol's brightness varies
1686 — Gottfried Kirch notices that Chi Cygni's brightness varies
1718 — Edmund Halley discovers stellar proper motions by comparing his astrometric measurements with those of the Greeks
1782 — John Goodricke notices that the brightness variations of Algol are periodic and proposes that it is partially eclipsed by a body moving around it
1784 — Edward Pigott discovers the first Cepheid variable star
1838 — Thomas Henderson, Friedrich Struve, and Friedrich Bessel measure stellar parallaxes
1844 — Friedrich Bessel explains the wobbling motions of Sirius and Procyon by suggesting that these stars have dark companions
1906 — Arthur Eddington begins his statistical study of stellar motions
1908 — Henrietta Leavitt discovers the Cepheid period-luminosity relation
1910 — Ejnar Hertzsprung and Henry Norris Russell study the relation between magnitudes and spectral types of stars
1924 — Arthur Eddington develops the main sequence mass-luminosity relationship
1929 — George Gamow proposes hydrogen fusion as the energy source for stars
1938 — Hans Bethe and Carl von Weizsäcker detail the proton-proton chain and CNO cycle in stars
1939 — Rupert Wildt realizes the importance of the negative hydrogen ion for stellar opacity
1952 — Walter Baade distinguishes between Cepheid I and Cepheid II variable stars
1953 — Fred Hoyle predicts a carbon-12 resonance to allow stellar triple alpha reactions at reasonable stellar interior temperatures
1961 — Chūshirō Hayashi publishes his work on the Hayashi track of fully convective stars
1963 — Fred Hoyle and William A. Fowler conceive the idea of supermassive stars
1964 — Subrahmanyan Chandrasekhar and Richard Feynman develop a general relativistic theory of stellar pulsations and show that supermassive stars are subject to a general relativistic instability
1967 — Eric Becklin and Gerry Neugebauer discover the Becklin-Neugebauer Object at 10 micrometres
1977 — (May 25) The Star Wars film is released and became a worldwide phenomenon, boosting interests in stellar systems.
2012 — (May 2) First visual proof of existence of black-holes. Suvi Gezari's team in Johns Hopkins University, using the Hawaiian telescope Pan-STARRS 1, publish images of a supermassive black hole 2.7 million light-years away swallowing a red giant.Urca process
In astroparticle physics, an Urca process is a reaction which emits a neutrino and which is assumed to take part in cooling processes in neutron stars and white dwarfs. The process was first discussed by George Gamow and Mário Schenberg while they were visiting a casino named Cassino da Urca in Rio de Janeiro. Schenberg is reported to have said to Gamow that "the energy disappears in the nucleus of the supernova as quickly as the money disappeared at that roulette table". In Gamow's South Russian dialect, urca (Russian: урка) can also mean a robber or gangster.The direct Urca processes are the simplest neutrino-emitting processes and are thought to be central in the cooling of neutron stars. They have the general form
where B1 and B2 are baryons, ℓ is a lepton, and νl (and νl) are (anti-)neutrinos. The baryons can be nucleons (free or bound), hyperons like Λ, Σ and Ξ, or members of the Δ isobar. The lepton is either an electron or a muon.
The Urca process is especially important in the cooling of white dwarfs, where a lepton (usually an electron) is absorbed by the nucleus of an ion and then convectively carried away from the core of a star. Then, a beta decay occurs. Convection then carries the element back into the interior of the star, and the cycle repeats many times. Because the neutrinos emitted during this process are unlikely to be reabsorbed, this is effectively a cooling mechanism for white dwarfs.The process can also be essential in the cooling of neutron stars. If a neutron star contains a central core in which the direct Urca-process is operative, the cooling timescale shortens by many orders of magnitude.V. G. Khlopin Radium Institute
The V. G. Khlopin Radium Institute, also known as the First Radium Institute, is a research and production institution located in Saint Petersburg specializing in the fields of nuclear physics, radio- and geochemistry, and on ecological topics, associated with the problems of nuclear power engineering, radioecology, and isotope production. It is a subsidiary company of the Rosatom Russian state corporation.The Institute was founded as State Radium Institute in 1922 under the initiative of V. I. Vernadskiy, integrating all radiological enterprises present in St. Petersburg (then Petrograd) at that time. This also included a factory in Bondyuga (Tatarstan), which was used by Vitaly Khlopin and others to generate Russia's first high-enriched radium compound. The Radium Institute was renamed to V. G. Khlopin in his honor in 1950.At the Radium Institute, the first European cyclotron was proposed by George Gamow and Lev Mysovskii in 1932, being constructed with the help of Igor Kurchatov, operational by 1937.Ylem
Ylem is a term that was used by George Gamow, his student Ralph Alpher, and their associates in the late 1940s for a hypothetical original substance or condensed state of matter, which became subatomic particles and elements as we understand them today. The term ylem was actually resuscitated (it appears in Webster's Second "the first substance from which the elements were supposed to have been formed") by Ralph Alpher.In modern understanding, the "ylem" described as by Gamow was the primordial plasma, formed in baryogenesis, which underwent Big Bang nucleosynthesis and was opaque to radiation. Recombination of the charged plasma into neutral atoms made the Universe transparent at the age of 380,000 years, and the radiation released is still observable as cosmic microwave background radiation.