Hans Albrecht Bethe (1906 - 2005)

Bethe was born in Straßburg (then part of Germany, now Strasbourg, France). He studied physics at Frankfurt and obtained his doctorate from the University of Munich, after which he did postdoctoral stints in Cambridge and at Enrico Fermi's laboratory in Rome. He left Germany in 1933 when the Nazis came to power and he lost his job (his mother was Jewish) at the University of Tubingen, moving first to England where he held a provisory position of Lecturer for the year 1933-1934 and in the fall of 1934, a fellowship at the University of Bristol. In 1935 Bethe moved to the United States, where he taught as a professor at Cornell University. At Cornell, Bethe became known as one of the leading theoretical physicists of his generation. He published a series of articles on nuclear physics, summarizing most of what was known until that time, an account that became informally known as 'Bethe's Bible', and remained the standard work on the subject for many years. In 1941 he became a naturalized citizen of the United States. During World War II, he served as part of a special summer session at the University of California, Berkeley at the invitation of Robert Oppenheimer, which outlined the first designs for the atomic bomb. Initially, Bethe had been skeptical about the possibility of making a nuclear weapon from uranium, but when his friend Edward Teller showed him the atomic pile that Enrico Fermi was building uder the football stands at the University of Chicago, he became convinced that such a project might actually be feasible. When Oppenheimer started the secret weapons design laboratory, Los Alamos, he appointed Bethe as Director of the Theoretical Division. After the war, Bethe argued that a crash project for the hydrogen bomb should not be attempted, though after President Truman announced the beginning of such a crash project, and the outbreak of the Korean War, Bethe signed up and played a key role in the weapon's development. Though he would see the project through to its end, in Bethe's account he personally hoped that it would be impossible to create the hydrogen bomb. From 1935 - 1938, he studied nuclear reactions and reaction cross sections (carbon-oxygen-nitrogen cycle). This research was useful to Bethe in more quantitatively developing Niels Bohr's theory of the compound nucleus. He received the Max Planck medal in 1955. In 1961 he was awarded the Eddington Medal of the Royal Astronomical Society for work in identifying the energy generating processes in stars. In 1967, Bethe was awarded the Nobel Prize in Physics "for his contributions to the theory of nuclear reactions, especially his discoveries concerning the energy production in stars" . He postulated that the source of this energy are thermonuclear reactions in which hydrogen is converted into helium. See: stellar nucleosynthesis. Bethe was noted for his theories on atomic properties. In the late 1940s, he provided the first way out of the infinities that plagued the explanation of the so called Lamb shift. This work was the impetus for the pioneering later work done by Richard Feynman, Julian Schwinger and others which marked the beginning of modern quantum electrodynamics. In 1960, Bethe, along with IBM physicist Richard Garwin, wrote an article criticising in detail the new anti- ICBM defense system that the Government was planning to install. In the article that was published in Scientific American, the two physicists described in detail how almost any countermeasure that the US could take would be futile, as the enemy would be able to thwart the system through the use of suitable decoys. During the '80s and '90s Bethe campaigned for the peaceful use of nuclear energy. After the Chernobyl accident, Bethe put together a committee of experts that analysed the incident, and concluded that a similar episode would not happen in any good US reactor, as the Russian reactor suffered from a fundamentally faulty design and human error also had significantly contributed to the accident. Throughout his life, Bethe remained a strong advocate for electricity from nuclear energy. In the 1980s, he, along with other physicists widely opposed the Strategic Defense Initiative missile system that was being conceived by the Reagan administration, arguing against the enormous sums of money spent on it and the feelings of instability and animosity that it would foster. In 1995, at the age of 88, Bethe wrote an open letter calling on all scientists to "cease and desist" from working on any aspect of nuclear weapons development and manufacture. In 2004, he signed a letter along with 47 other Nobel laureates endorsing John Kerry for president of the United States citing Bush's misuse of science. He continued to do research on supernovae, neutron stars, black holes, and other problems in theoretical astrophysics into his late nineties. In doing this, he collaborated with Gerald Brown of SUNY-Stony Brook. The asteroid 30828 Bethe is named after him. In his 80s, he wrote an important article about the solar neutrino problem. He won the Bruce Medal in 2001. Hans Bethe died in his home in Ithaca, New York. At the time of his death, he was the John Wendell Anderson Professor of Physics Emeritus at Cornell University. He is survived by his wife Rose, his son Henry and his daughter Monica.

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