George Gamow

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Ukrainian–American physicist (1904–1968)

Gamow was born the son of a teacher at Odessa, now in Ukraine. He was educated at the University of Leningrad where he obtained his doctorate in 1928 and later served as professor of physics (1931–34). Before his move to America in 1934 he spent long periods at Göttingen, Copenhagen, and Cambridge, England, the major centers of the revolution then taking place in physics. In America he spent his career as professor of physics at George Washington University (1934–55) and then at the University of Colorado (1956–68).

Gamow made many contributions to nuclear and atomic physics, but is mainly noted for his work on interesting problems in cosmology and molecular biology.

In cosmology he revised and extended the big-bang theory of the creation of the universe (first formulated by Georges Lemaître). This postulates that the universe expanded from a single point in space and time. It was first announced in Gamow's famous ‘alpha beta gamma’ paper in 1948, which he wrote in collaboration with Ralph Alpher (1921––sp;–sp;) and Hans Bethe. A fuller account was later published by Gamow in his Creation of the Universe (1952). Gamow dated the expansion to about 17 billion years ago, probably the result of an earlier contraction. The difficulty with any such theory was in accounting for the formation of the chemical elements. He supposed the primeval atom to consist of ‘Ylem’, an old word used by Gamow to refer to a mixture of protons, electrons, and neutrons. Using the conditions of temperature and density prevailing in the first half hour of the universe's history he tried to work out ways in which the elements could be formed by nuclear aggregation. There was no difficulty in showing that ¹H, ²H, ³H, ³He, and ⁴He would be formed but at that point he could see no way to advance the chain further, for there is no stable element with an atomic weight of 5. Add either a proton or a neutron to the nucleus of ⁴He and either ⁵Li or ⁵He will be formed, both of which are unstable and decay in less than 10^–20 sec back to the original ⁴He.

The only solution was to suppose that more than one particle collided with the ⁴He nucleus simultaneously but, as Gamow realized, the universe by this time would be insufficiently dense and hot enough to permit such collisions to occur with the required frequency. He was therefore forced to conclude in 1956 that most of the heavy elements have been formed later in the hot interior of stars. One prediction that did emerge from his work and was to have important consequences for cosmology was his claim that the original explosion would produce a uniform radiation background; the discovery of such radiation in 1964 by Arno Penzias and Robert Wilson did more than anything else to stimulate interest once more in Gamow's theory.

Gamow later moved from showing how the universe began to the no less interesting question of how life began. He was quick to see the significance of the DNA model proposed by James Watson and Francis Crick in 1953. The problem was to show how the sequences of the four nucleic acid bases that constitute the DNA chain could control the construction of proteins, which may be made from 20 or more amino acids. Gamow had the insight to see that the bases must contain a code for the construction of amino acids. But the question of how this worked still remained. It could not be one base to one amino acid for then there would be only four amino acids. Nor would two bases be sufficient for they could produce only 4 × 4 = 16 amino acids. It would therefore need a sequence of three bases to produce one amino acid, a language with a capacity of 4 × 4 × 4 = 64 words, which was more than adequate for the construction of all proteins. Gamow also produced convincing arguments to show that the code is not overlapping.

The work on DNA allowed Gamow to indulge his passion for science fantasy. He founded the RNA tie club for which he actually designed a tie. It was restricted to 20 members, one for each amino acid. Each member took the name of one of the acids – Gamow was ‘phe’ (the usual abbreviation for phenylalanine) while Crick was ‘tyr’ (tyrosine). Meetings were held, information was exchanged, and considerable progress was made.

Gamow was also known as one of the most successful popular science writers of his day. He wrote many books, most of which are still in print, which convey much of the excitement of the revolution in physics that he lived through.

The Russian-American physicist George Gamow (1904-1968) made important contributions to nuclear physics. He also did significant work in the fields of astrophysics and biology and wrote books popularizing science.

George Gamow was born in Odessa, Russia, on March 4, 1904. He became interested in physics at an early age, and when he was 18 he enrolled in the physico-mathematical faculty at Novorossia University in Odessa. After a year he transferred to the University of Leningrad, from which he eventually received a Ph.D. in 1928. That summer he visited the university in Göttingen, Germany. His work impressed the Danish physicist Niels Bohr so much that he was invited to be a fellow of theoretical physics at the University of Copenhagen. He remained in Denmark for one year, then spent the next year studying with Ernest Rutherford at the Cavendish Laboratory in England. He subsequently returned to the University of Copenhagen for another year.

In 1931 Gamow accepted the position of professor of physics at the University of Leningrad. After denying him permission to leave the country for two years, the Soviet government allowed him and his wife, Lynbov Vokhminzeva, to attend the 1933 Solvay Congress in Belgium; he took this opportunity to leave the Soviet Union forever. He spent the rest of the year at various scientific institutions all over Europe and was appointed professor of physics at the George Washington University in Washington, D.C., in 1934. Gamow remained there until 1956, when he transferred to the University of Colorado and divorced his wife. He married Barbara Perkins in 1958, and they remained in Colorado until his death in 1968. His career was extremely diverse: he delved into nuclear physics, astrophysics, biology, and writing.

Gamow's first major contribution to nuclear physics took place in Göttingen. He was intrigued by an unusual phenomenon that Rutherford had reported as a result of an alpha particle scattering experiment. When a uranium sample is bombarded with alpha particles (positively charged particles composed, like helium nuclei, of two protons and two neutrons), the particles are repelled by the electrostatic force exerted on them by the uranium nuclei, which are also positively charged. However, a uranium nucleus already contains alpha particles, and these remain there for a long time because the repulsive force exerted by a nucleus on alpha particles is overcome by the attractive force of the strong nuclear interactions at very close distances. The classical theories of physics maintained that the particles could never leave the nucleus because of the barrier that is created at the distance where the repulsive force becomes an attractive one. What puzzled Rutherford was that some alpha particles do leak out of the nucleus, though very slowly.

Gamow applied the new wave mechanics theories to this problem. In wave mechanics, the motion of particles is determined by "pilot waves," which are waves that can penetrate through any barrier. He showed that the alpha particles were in a sense "riding" on the pilot waves, enabling them to "tunnel" out through the barrier. This theory explained not only Rutherford's puzzle but also the relationship between the alpha particles emitted by different radioactive substances and the half-lives of the substances.

Gamow's second major contribution to nuclear physics was in the form of the Gamow-Teller selection rule for beta decay, a process whereby the nucleus of a radioactive atom emits an electron, thereby transforming itself into a different atom. In his theory of beta decay, Enrico Fermi had said that the electron leaves the nucleus straight out along the radius vector. Working with Edward Teller, Gamow showed that the electron could escape just as easily by moving in a hyperbolic trajectory. This discovery brought considerable insight into the magnetic interaction between the electron and the nucleus.

After this work Gamow turned his attention towards the application of nuclear physics to astrophysics. There had been previous, unsuccessful attempts to explain the abundance of nuclei in the cosmos in terms of thermodynamic equilibrium conditions. One of the problems with this approach was that the conditions for the formation of heavier nuclei were not the same as those for the formation of lighter nuclei. Gamow advocated the theory of the big bang and the expanding universe as a means of resolving the problem. He theorized that before the bang there was a fundamental state of matter he called "ylem" that consisted of a mixture of neutrons, electrons, and protons held together in a ball of high energy radiation. This ball then exploded and began to expand, allowing the fundamental particles to combine and form nuclei, and, eventually, elements - this is a process known as nucleo synthesis. He suggested that because such a universe was continually expanding, and hence changing, there would be sufficiently diverse conditions for elements of all different atomic weights to form in a non-equilibrium process. This theory also led Gamow to predict that there should be a certain level of remnant radiation from the big bang. This radiation was discovered accidentally almost 20 years later by researchers at Bell labs.

In 1954 Gamow turned to the field of biology, building on the work done by Francis Crick and James Watson on the helical structure of DNA (deoxyribonucleic acid). Gamow's work was in genetic coding theory, which deals with the way information is transferred in the genes. He used combinatorial mathematics to show that it was possible to establish the validity of certain proposed coding schemes by studying known sequences of amino acids.

Gamow also wrote many books popularizing science in an entertaining, innovative manner. This achievement won him the UNESCO Kalinga Award in 1956. He was a member of numerous scientific societies, among them the American Physical Society, the Washington Philosophical Society, the International Astronomical Union, and the Royal Danish Academy of Sciences and Letters.

Further Reading

Among the many books Gamow wrote to explain science to the layman are the well-known Mr. Tompkins books. Mr. Tompkins in Wonderland (1940) explains the theory of relativity, and Mr. Tompkins Explores the Atom (1944) discusses modern theories of the atom. He wrote several books on cosmology, including The Moon (1953) and a trilogy published in 1955 composed of The Birth and Death of the Sun, Biography of the Earth, and The Creation of the Universe. He had also been working on an autobiography, My World Line, at the time of his death. Incomplete, the book was published post-humously in 1970.

George Gamow
Born	March 4, 1904(1904-03-04) Odessa, Russian Empire
Died	August 19, 1968 (aged 64) Boulder, Colorado, US
Nationality	United States, Russia
Fields	Physicist, Science writer
Institutions	University of Göttingen Niels Bohr Institute Cavendish Laboratory The George Washington University University of California, Berkeley University of Colorado at Boulder
Doctoral advisor	Alexander Friedmann
Known for	Cosmic microwave background radiation, Quantum tunnelling, Big Bang
Notable awards	Kalinga Prize (1956)

George Gamow (Russian pronunciation: [ˈɡaməf]; March 4, 1904 – August 19, 1968) , born Georgiy Antonovich Gamov (Георгий Антонович Гамов), was a Russian Empire-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 Radiation, nucleocosmogenesis and genetics.

Contents 1 Life and early career 2 Big bang theory work 3 DNA and later career 4 Writings 5 Books 5.1 Popular 5.1.1 Mr. Tompkins series 5.2 Science textbooks 6 See also 7 References 8 External links

Life and early career

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 two other students of theoretical physics, Lev Landau and Dmitri Ivanenko. The three 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.

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, 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 the early 1900s, 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 had solved the theory of the alpha decay of a nucleus via tunnelling, with mathematical help from Kochin^[1]. Classically, the particle is confined to the nucleus because of the high energy requirement to escape the very strong potential. Also classically, it takes an enormous amount of energy to pull apart the nucleus. In quantum mechanics, however, there is a probability the particle can tunnel through the potential 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. (For Gamow's derivation of this law, see [1].)

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, where he published articles with Edward Teller, Mario Schenberg and Ralph Alpher. Gamow became a naturalized American in 1940.

Big bang theory work

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 not had any 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, Ralph 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.

Gamow published another paper in the British journal Nature later 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).

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.

DNA and later career

Grave of George Gamow in Green Mountain Cemetery, Boulder, Colorado, USA

After the discovery of the structure of DNA in 1953 by Francis Crick and James Watson, Gamow attempted to solve the problem of how the order of the four different kinds of bases (adenine, cytosine, thymine and guanine) in DNA chains could control the synthesis of proteins from amino acids.^[2] Crick has said^[3] that Gamow's suggestions helped him in his own thinking about the problem. As related by Crick,^[4] Gamow suggested that the twenty combinations of four DNA bases taken three at a time correspond to twenty amino acids used to form proteins. This led Crick and Watson to enumerate the twenty amino acids which are common to most proteins.

However the specific system proposed by Gamow (known as "Gamow's diamonds") was incorrect, as 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 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.

Gamow later created an informal RNA Tie club. He had some ties and tie clips created for the club and the members were his circle of accomplished friends within the discipline. At times some members did get together to discuss abstract issues such as deriving the genetic code from first principles. In this sense, the club produced no results but it did set a disciplined scientific tone for which to consider such problems.

Gamow remained at George Washington University until 1954, then worked at University of California, Berkeley (1954), and University of Colorado at Boulder (1956–1968).

On August 19, 1968, George Gamow died at age 64 in Boulder, Colorado, and was buried there in Green Mountain Cemetery. The University of Colorado at Boulder Physics department tower is named after him.

The George Gamow Tower at the University of Colorado at Boulder

Writings

Gamow was a highly successful science writer, with several of his books still in print. He conveyed the excitement of the revolution in physics and other scientific topics of interest to the common reader. Gamow himself prepared the illustrations for his books, which added a new dimension to and complemented what Gamow intended to convey in the text. Wherever it was essential, he used mathematics.

In 1956, he was awarded the Kalinga Prize by UNESCO for his work in popularizing science with his Mr. Tompkins... series of books (1939–1967), One Two Three ... Infinity, and other works.

Gamow was working on a textbook entitled Basic Theories in Modern Physics, with Richard Blade, but it was not completed before he died. He wrote a book entitled My World Line: An Informal Autobiography, which was published posthumously in 1970.

Books

Popular

• The Birth and Death of the Sun (1940)
• The Biography of the Earth (1941)
• One, Two, Three...Infinity (1947), Viking Press (copyright renewed by Barbara Gamow, 1974), Dover Publications, ISBN 0-486-25664-2, illustrated by the author. Dedicated to his son, Igor Gamow ("who wanted to be a cowboy") The book winds from mathematics to biology, through physics, crystallography, and more.
• The Moon (1953)
• Gamow, George; Stern, Marvin (1958), Puzzle-Math, Viking Press, ISBN 978-0-333-08637-7 

• Biography of Physics (1961)
• Gravity (1962) Dover Publications, ISBN 0-486-42563-0. Profiles of Galileo, Newton, and Einstein
• A Planet Called Earth (1963)
• A Star Called the Sun (1964)
• Thirty Years That Shook Physics: The Story of Quantum Theory, 1966, Dover Publications, ISBN 0-486-24895-X. Illustrated by the author and with period photographs, Gamow describes an insider's view of the development of quantum theory. Having worked with Niels Bohr and Ernest Rutherford, he not only can expound the theory, he supplies candid photos of Edward Teller on skis, Bohr on a motorcycle, Werner Heisenberg having a swim, and Enrico Fermi playing tennis. The finale is a dramatic playscript (also illustrated) of the history of atomic physics with the scientists cast in roles after the model of Goethe's Faust.
• My World Line: An Informal Autobiography (1970) Viking Press, ISBN 0-670-50376-2

Mr. Tompkins series

• Mr. Tompkins in Wonderland (1940) Originally published in serial form in Discovery magazine (UK) in 1938.
• Mr. Tompkins Explores the Atom (1945)
• Mr. Tompkins Learns the Facts of Life (1953), about biology
• Mr. Tompkins in Paperback (1965), combines Mr. Tompkins in Wonderland with Mr. Tompkins Explores the Atom, Cambridge University Press, 1993 Canto edition with foreword by Roger Penrose, ISBN 0-521-44771-2. Creatively illustrated by the author, and complete with a scored musical composition ("The Cosmic Opera"), the book explains the principles of relativity and quantum theory in a fashion that is entertaining to young people and adults.
• Mr. Tompkins Inside Himself (1967), A rewritten version of Mr. Tompkins Learns the Facts of Life gives a broader view of biology, including recent developments in molecular biology. It was coauthored by M. Ycas.

Throughout these books, Tompkins is introduced as "C. G. H. Tompkins" to emphasize the notion of cGħ physics.

Science textbooks

• The Constitution of Atomic Nuclei and Radioactivity (1931)
• Structure of Atomic Nuclei and Nuclear Transformations (1937)
• Atomic Energy in Cosmic and Human Life (1947)
• Theory of Atomic Nucleus and Nuclear Energy Sources (1949) coauthor C. L. Critchfield
• The Creation of the Universe (1952)
• Matter, Earth and Sky (1958)
• Physics: Foundations & Frontiers (1960) coauthor John M. Cleveland
• The Atom and its Nucleus (1961)
• Mr. Tompkins Gets Serious: The Essential George Gamow (2005) Pi Press, ISBN 0-13-187291-5. Incorporates material from Matter, Earth, and Sky and The Atom and Its Nucleus. Notwithstanding the title, this book is not part of the Mr. Tompkins series.

See also

• Urca process
• Ylem

References

1. ^ http://www.aip.org/history/ohilist/4325.html Interview with George Gamow by Charles Weiner at Professor Gamow's home in Boulder, Colorado, April 25, 1968. (In the transcript Kochin is spelled Kotshchin.)
2. ^ Segrè, Gino (2000-03-30), "The Big Bang and the genetic code", Nature 404 (6777): 437, doi:10.1038/35006517, http://www.nature.com/cgi-taf/DynaPage.taf?file=nature/journal/v404/n6777/full/404437a0_r.html 
3. ^ "DNA: An "Amateur" Makes a Real Contribution". http://www.loc.gov/exhibits/treasures/trr115.html. Retrieved 2007-07-11. 
4. ^ Crick, Francis "What Mad Pursuit" (Basic Books 1998), Chap.8 The Genetic Code

External links

Wikiquote has a collection of quotations related to: George Gamow

Wikimedia Commons has media related to: George Gamow

• Memorial Lecture Series (University of Colorado, at Boulder)
• Brief biography
• "Getting a Bang Out of Gamow"
• "A Respectable Scientist" ~ Signal + Noise : All Models Are False, Some Are Useful (28 November 2003)
• Biographic sketch (in PDF)
• Gamow Books
• Complete Gamow bibliography
• Annotated bibliography for George Gamow from the Alsos Digital Library for Nuclear Issues
• Gamow memorial at George Washington University
• George Gamow: Combining physics with humor
• [http://www.aip.org/history/ohilist/4325.html Oral History interview transcript with George
• http://images.google.com.au/imgres?imgurl=http://www.nndb.com/people/349/000099052/george-gamow-1-sized.jpg&imgrefurl=http://www.nndb.com/people/349/000099052/&usg=__UkHGUg2JUgBaAcpy9IVOqOSyT_s=&h=323&w=241&sz=23&hl=en&start=1&um=1&tbnid=hMllLEm587Ba7M:&tbnh=

Gamow 25 April 1968, American Institute of Physics, Niels Bohr Library and Archives]

Persondata
NAME	Gamow, George
ALTERNATIVE NAMES	Georgiy Antonovich Gamov, Георгий Антонович Гамов
SHORT DESCRIPTION	Russian-American physicist and science writer
DATE OF BIRTH	1904-3-4
PLACE OF BIRTH	Odessa, Russian Empire
DATE OF DEATH	1968-8-19
PLACE OF DEATH	Boulder, Colorado, US

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