by neufer » Sat Oct 02, 2010 1:16 pm
Chris Peterson wrote:
Adventures, indeed!
http://en.wikipedia.org/wiki/Alexander_Friedmann wrote:
Alexander Alexandrovich Friedman or Friedmann (Александр Александрович Фридман) (June 16, 1888, Saint Petersburg, Russian Empire – September 16, 1925, Leningrad, USSR) was a Russian and Soviet cosmologist and mathematician. Alexander Friedmann lived much of his life in Saint Petersburg.
He fought in World War I (on behalf of Imperial Russia) as a bomber and later lived through the Russian Revolution of 1917.
He discovered the expanding-universe solution to the general relativity field equations in 1922, which was corroborated by Edwin Hubble's observations in 1929. Friedmann's 1924 papers, including "Über die Möglichkeit einer Welt mit konstanter negativer Krümmung des Raumes" (On the possibility of a world with constant negative curvature of space) published by the German physics journal Zeitschrift für Physik (Vol. 21, pp. 326-332), demonstrated that he had command of all three Friedmann models describing positive, zero and negative curvature respectively, a decade before Robertson and Walker published their analysis. This dynamic cosmological model of general relativity would come to form the standard for the Big Bang and steady state theories. Friedmann's work supports both theories equally, so it was not until the detection of the cosmic microwave background radiation that the steady state theory was abandoned in favor of the current favorite Big Bang paradigm. Another famous physicist, George Gamow, was a student of Friedmann.
In addition to general relativity, Friedmann's interests included hydrodynamics and meteorology. In July 1925 he participated in a record-setting balloon flight, reaching the elevation of 7,400 m (24,300 ft). Friedmann died on September 16, 1925, at the age of 37, from typhoid fever that he contracted during a vacation in
Crimea.>>
http://en.wikipedia.org/wiki/George_Gamow wrote:
<<George Gamow (March 4 [O.S. February 20] 1904 – August 19, 1968), born Georgiy Antonovich Gamov (Георгий Антонович Гамов), was a Russian-born theoretical physicist and cosmologist. He discovered alpha decay via quantum tunneling and worked on radioactive decay of the atomic nucleus, star formation, stellar nucleosynthesis, big bang nucleosynthesis, cosmic microwave background, nucleocosmogenesis and genetics.
Gamow was born in the city of Odessa, Russian Empire (now in Ukraine) to mixed Russian-Ukrainian parents. He was educated at the Novorossiya University in Odessa (1922–23) and at the University of Leningrad (1923–1929). Gamow studied under Alexander Friedmann for some time in Leningrad, though Friedmann died in 1925. At the University Gamow made friends with three other students of theoretical physics, Lev Landau, Dmitri Ivanenko, and Matvey Bronshtein (who was arrested in 1937 and executed in 1938 by the Soviet regime). 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.
Gamow then worked at a number of Soviet establishments before deciding to flee Russia because of increased oppression. His first two attempts to defect with his wife, Lyubov Vokhminzeva, were in 1932 and involved attempting to kayak: first a 250-kilometer paddle over the Black Sea to Turkey and then from Murmansk to Norway. Poor weather foiled both attempts. In 1933, the two tried a less dramatic approach - Gamow managed to obtain permission for himself and his wife (who was also a physicist) to attend the Solvay Conference for physicists in Brussels. The two attended and promptly defected. In 1934, they moved to the United States. He began working at The George Washington University in 1934. Gamow became a naturalized American in 1940.
Gamow produced an important cosmogony paper with his student Ralph Alpher, which was published as "The Origin of Chemical Elements" (Physical Review, April 1, 1948). This paper became known as the Alpher-Bethe-Gamow theory. Gamow had the name of Hans Bethe listed on the article as "H. Bethe, Cornell University, Ithaca, New York" to make a pun on the first three letters of the Greek alphabet, alpha, beta and gamma. Bethe had no other role in the α-β-γ paper. The paper outlined how the present levels of hydrogen and helium in the universe (which are thought to make up over 99% of all matter) could be largely explained by reactions that occurred during the "big bang". This lent theoretical support to the Big Bang theory, although it did not explain the presence of elements heavier than helium (this was done later by Fred Hoyle). In this paper, no estimate of the strength of the present day residual cosmic microwave background radiation (CMB) was made. Shortly thereafter, Alpher and Robert Herman predicted that the afterglow of the big bang would have cooled down after billions of years, filling the universe with a radiation five degrees above absolute zero. Astronomers and scientists did not make any effort to detect this background radiation at that time, due to both a lack of interest and the immaturity of microwave observation. Consequently, Gamow's prediction in support of the big bang was not substantiated until 1964, when Arno Penzias and Robert Wilson made the accidental discovery for which they were awarded the Nobel Prize in Physics in 1978. Their work determined that the universe's background radiation was 2.7 degrees above absolute zero, just 2.3 degrees lower than Gamow's 1948 prediction.
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).>>
[quote="Chris Peterson"][quote="RJN"][url]http://adsabs.harvard.edu/abs/2008AmJPh..76..265N[/url][/quote]
Adventures, indeed![/quote]
[quote=" http://en.wikipedia.org/wiki/Alexander_Friedmann"]
[float=right][img]http://upload.wikimedia.org/wikipedia/commons/thumb/6/62/Aleksandr_Fridman.png/200px-Aleksandr_Fridman.png[/img][/float]Alexander Alexandrovich Friedman or Friedmann (Александр Александрович Фридман) (June 16, 1888, Saint Petersburg, Russian Empire – September 16, 1925, Leningrad, USSR) was a Russian and Soviet cosmologist and mathematician. Alexander Friedmann lived much of his life in Saint Petersburg.[b][color=#0000FF] He fought in World War I (on behalf of Imperial Russia) as a bomber and later lived through the Russian Revolution of 1917.
[/color][/b]
He discovered the expanding-universe solution to the general relativity field equations in 1922, which was corroborated by Edwin Hubble's observations in 1929. Friedmann's 1924 papers, including "Über die Möglichkeit einer Welt mit konstanter negativer Krümmung des Raumes" (On the possibility of a world with constant negative curvature of space) published by the German physics journal Zeitschrift für Physik (Vol. 21, pp. 326-332), demonstrated that he had command of all three Friedmann models describing positive, zero and negative curvature respectively, a decade before Robertson and Walker published their analysis. This dynamic cosmological model of general relativity would come to form the standard for the Big Bang and steady state theories. Friedmann's work supports both theories equally, so it was not until the detection of the cosmic microwave background radiation that the steady state theory was abandoned in favor of the current favorite Big Bang paradigm. Another famous physicist, George Gamow, was a student of Friedmann.
In addition to general relativity, Friedmann's interests included hydrodynamics and meteorology. In July 1925 he participated in a record-setting balloon flight, reaching the elevation of 7,400 m (24,300 ft). Friedmann died on September 16, 1925, at the age of 37, from typhoid fever that he contracted during a vacation in [b][color=#FF0000]Crimea[/color][/b].>>[/quote][quote=" http://en.wikipedia.org/wiki/George_Gamow"]
[float=right][img]http://upload.wikimedia.org/wikipedia/commons/thumb/6/67/GamovGA_1930.jpg/150px-GamovGA_1930.jpg[/img][/float]<<George Gamow (March 4 [O.S. February 20] 1904 – August 19, 1968), born Georgiy Antonovich Gamov (Георгий Антонович Гамов), was a Russian-born theoretical physicist and cosmologist. He discovered alpha decay via quantum tunneling and worked on radioactive decay of the atomic nucleus, star formation, stellar nucleosynthesis, big bang nucleosynthesis, cosmic microwave background, nucleocosmogenesis and genetics.
[color=#0000FF]Gamow was born in the city of Odessa, Russian Empire (now in Ukraine) to mixed Russian-Ukrainian parents.[/color] He was educated at the Novorossiya University in Odessa (1922–23) and at the University of Leningrad (1923–1929). Gamow studied under Alexander Friedmann for some time in Leningrad, though Friedmann died in 1925. At the University Gamow made friends with three other students of theoretical physics, Lev Landau, Dmitri Ivanenko, and Matvey Bronshtein (who was arrested in 1937 and executed in 1938 by the Soviet regime). 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.
[color=#0000FF]Gamow then worked at a number of Soviet establishments before deciding to flee Russia because of increased oppression. His first two attempts to defect with his wife, Lyubov Vokhminzeva, were in 1932 and involved attempting to kayak: first a 250-kilometer paddle over the Black Sea to Turkey and then from Murmansk to Norway. Poor weather foiled both attempts.[/color] In 1933, the two tried a less dramatic approach - Gamow managed to obtain permission for himself and his wife (who was also a physicist) to attend the Solvay Conference for physicists in Brussels. The two attended and promptly defected. In 1934, they moved to the United States. He began working at The George Washington University in 1934. Gamow became a naturalized American in 1940.
[b][color=#FF00FF]Gamow produced an important cosmogony paper with his student Ralph Alpher, which was published as "The Origin of Chemical Elements" (Physical Review, April 1, 1948). This paper became known as the Alpher-Bethe-Gamow theory. Gamow had the name of Hans Bethe listed on the article as "H. Bethe, Cornell University, Ithaca, New York" to make a pun on the first three letters of the Greek alphabet, alpha, beta and gamma. Bethe had no other role in the α-β-γ paper.[/color][/b] The paper outlined how the present levels of hydrogen and helium in the universe (which are thought to make up over 99% of all matter) could be largely explained by reactions that occurred during the "big bang". This lent theoretical support to the Big Bang theory, although it did not explain the presence of elements heavier than helium (this was done later by Fred Hoyle). In this paper, no estimate of the strength of the present day residual cosmic microwave background radiation (CMB) was made. Shortly thereafter, Alpher and Robert Herman predicted that the afterglow of the big bang would have cooled down after billions of years, filling the universe with a radiation five degrees above absolute zero. Astronomers and scientists did not make any effort to detect this background radiation at that time, due to both a lack of interest and the immaturity of microwave observation. Consequently, Gamow's prediction in support of the big bang was not substantiated until 1964, when Arno Penzias and Robert Wilson made the accidental discovery for which they were awarded the Nobel Prize in Physics in 1978. Their work determined that the universe's background radiation was 2.7 degrees above absolute zero, just 2.3 degrees lower than Gamow's 1948 prediction.
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).>>[/quote]