Hans Bethe

Hans Albrecht Bethe is an American physicist of German origin, born the July 2nd 1906 with Strasbourg then German and dead the March 6th 2005 with Ithaca in the state of New York. It exiled Germany in 1933 to settle definitively in the United States in 1935. He was prize winner of the Nobel Prize of physics in 1967 for his contribution to the comprehension of the stellar nucleosynthesis.

During the Second world war, it directed the division of theoretical physics of the National laboratory of Los Alamos which manufactured the first atomic bomb. Its team worked on the critical mass of Uranium 235 necessary to obtain a reaction of fission in chain.

The first atomic bomb of the history exploded on the site of Trinity in the desert of New Mexico the July 16th 1945. Witness of the explosion, Hans Bethe declared himself concerned only by the good success of the experiment and not by the implication which it would have for the world. He declared: " I am not a philosophe".

He also played a big role in the development of the Bombe to hydrogen in the years 1950.

Later, Bethe made countryside with Albert Einstein within the emergency Comité of the scientists nuclear physicists against the nuclear tests and the arms race.

It influenced near the White House for the signature of the treaties of prohibition of the atmospheric nuclear tests in 1963 like the missiles anti-ballistics (SALT I) in 1972.

Biography

Bethe was born with Strasbourg (then in Germany). He studied physics at the University of Frankfurt and obtained his doctorate at the University of Munich. He accomplished thereafter a stay postdoctoral with Cambridge and the laboratory of Enrico Fermi in Rome. He left Germany in 1933 when the Nazis arrived at the capacity and that he lost his work at the University of Tübingen (his/her mother was Jewish). He exiled himself first of all in the United Kingdom where he exerted a post of professor for the year 1933-1934 then of post-doctoral researcher starting from the autumn 1934 at the Bristol-board University.

In 1935, Hans Bethe went to the United States where it started to teach as a professor with the Université Cornell. In Cornell, Bethe was made known like one of the most talented theorists of its generation. It published a series of articles on the Nuclear physics, summarizing about totality of what was known then on the subject. These articles very quickly became known like the “Bethe' S Bible” and remained the standard of the discipline for many years. It was naturalized states-unien in 1941.

When the war burst, Bethe wanted to contribute to the effort of war. According to the councils of his friend Theodore von Karman, aerodynamicist with Caltech, Bethe collaborated with Edward Teller, then at the University George Washington on the theory of the shock waves produced by the passage of the projectiles through gases.

This work was later useful for the researchers who studied the missiles. Bethe also worked on a theory of the penetration of the shieldings.

During the summer 1942, it took part in special sessions of teaching to the university of Berkeley, California, where it was invited by Robert Oppenheimer. It was during these sessions that the first ideas of atomic bomb were imagined.

Initially, Bethe was skeptic on the possibility of producing a nuclear weapon starting from uranium (he had written a theoretical article in the Thirties rejecting the concept of nuclear fission), but when Teller showed him the Atomic pile that Enrico Fermi was building at the University of Chicago, Bethe was convinced that such a project was feasible.

When Oppenheimer created the secret laboratory devoted to the manufacture of the new nuclear weapons with Los Alamos, it engaged Bethe as a director of the division of theoretical physics, which irritated Teller with more not, him which had coveted this station so much. During the Project Manhattan, Klaus Fuchs, which made pass from the sensitive informations to the Russians, belonged to the team directed by Bethe. Like all the other scientist of the project, Bethe forever suspected Fuchs of being a spy.

After the end of Second world war, Bethe decided against the development of the Bombe to hydrogen, but after Harry Truman announced the implementation of this program and that the Guerre of Korea burst, Bethe was joined the team associated with this project with bomb with hydrogen and played a crucial role in its development. Although he wanted to see the project carried out in the long term, Bethe wished that it was impossible to produce such a weapon.

Between 1935 and 1938, he studied the nuclear reactions and the cross sections of the reactions of the Cycle carbon-nitrogenize-oxygen. This research was useful for the quantitative development of the theory of the atomic nucleus of Bohr. He accepted the Médaille max Planck in 1955 then the Franklin Médaille in 1959. In 1961, it accepted the Médaille Eddington of the Royal Astronomical Society for its work on the creative processes of energy in stars. Six years later, in 1967, Bethe accepted the Nobel Prize of physics for its contribution to the theory of the nuclear Reactions, and mainly its discoveries concerning the energy production in stars.

He had proposed that the source of this energy was reactions of thermonuclear fusion in which hydrogen is converted into helium (nucléosynthère stellar).

Bethe was known for these theories on the atomic properties. At the end of the years 1940, he proposed the first solution with infinite which appeared in the theory of the Décalage of Lamb. This work was the base of work pioneer continued later by Richard Feynman, Julian Schwinger and others which marked the beginning of the modern quantum electrodynamics.

In 1954, Bethe testified in favor of Robert Oppenheimer, which underwent a political lawsuit, being communist sympathizer. During this lawsuit, Bethe and his wife tried to convince Teller not to testify in discredit of Oppenheimer, but Teller refused and its testimony exploited a big role the exit of the lawsuit and the judgment of Oppenheimer.

Whereas Bethe and Teller had been in very good terms in the prewar years, the conflict appeared between them lasting the Manhattan project, and particularly during the Oppenheimer lawsuit, their relation darkens durably. In 1957, he becomes foreign member of the Royal Society.

In 1960, Bethe, with the physicist of IBM Richard Garwin, in detail wrote an article criticizing the new defense system anti-missile which the government states-unien prepared. In this article published in the review, the two physicists described in detail how any counter-attack that the United States could engage would be futile, owing to the fact that the enemy could thwart all the system by adapted easy ways. Bethe was one of the scientific voices more in sight behind the signature of the Treaty of prohibition partial of the atmospheric nuclear tests of 1963.

During years 1980 and 1990, Bethe made countryside for the peaceful use of nuclear energy. After the accident of Tchernobyl, Bethe set up a committee of experts to analyze the incident and concludes that a similar episode could not have arrived in an engine at the United States, owing to the fact that the Russian engine suffered from design defects and that human errors had also contributed strongly to the accident. During all its life, Bethe remained a fervent supporter of nuclear energy to produce electricity.

During years 1980, it was opposed savagely with other physicists to the program of " War of Etoiles" conceived by the administration Reagan, by proposing the enormous money sums concerned and the return of feelings of mistrust and animosity that was going to generate.

In 1995, then 88 years old, Bethe wrote an open letter inviting all the scientists to immediately cease any activity relating to the development of nuclear weapons. In 2004, it signed a letter with 47 other prizes winner of the Nobel Prize to encourage the candidature of John Kerry against George W. Bush, by showing this last of a misuse of science.

Bethe continued to carry out research tasks on the Supernova E, the neutron stars, the black holes and other problems of theoretical astrophysics until more than 90 years. The Astéroïde (30828) Bethe was named in its honor. Then octogenarian, it wrote an important article about the Problème of the solar neutrinos.

He was prize winner of the Médaille Bruce in 2001.

Bethe had a passion for the history and the collection of the stamps. On this subject, he declared one day that it was the only place where all the countries of the world could cohabit the ones beside the others in peace.

Hans Bethe died at his place with Ithaca in March 2005. He was then Professor of highly skilled physics to the Université Cornell.

Quotations

"Just has few months before, the Korean war had broken out, and for the first time I saw direct confrontation with the Communist S. It was too disturbing. The Cold war looked ace yew it were butt to get hot. I knew then I had to reverse my earlier position. Yew I didn' T work one the bomb, somebody else would -- and I had thought yew I were around Los Alamos I might still Be has force for disarmament. So I agreed to join in developing the H-bomb. It seemed quite logical. Goal sometimes I wish I were more consist year Idealist. " - 1968 (in Schweber, p.166)

"After the H-bomb was made, reporters started to cal Teller the father off the H-bomb. For the sake off history, I think it is more specifies to say that Ulam is the father, because He provided the seed, and Teller is the mother, because He remained with the child. Ace for me, I guess I amndt the midwife." - 1968 (Schweber, p.166)

References

Bernstein, Jeremy, Hans Bethe, Prophet off Energy , 1980
Bethe, Hans A., The Road from Los Alamos , NY: Simon and Schuster, 1991, ISBN 0671740121, nap collected essays one nuclear topics.
Schweber, S.S. In the shadow off the bomb: Bethe, moral Oppenheimer, and the responsibility off the scientist . Princeton, N.J.: Princeton University Near, 2000.

External bonds

Hans Bethe Nobel readings
Hans Bethe World off Science
Hans Bethe Britannica Nobel Prizes
Text of the speech of handing-over of the medal Eddington
Page of the medal Bruce
Three courses in video by Hans Bethe

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