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One of the fathers of the atom bomb and one of the greatest scientists of the 20th century. 
This guy was seriously good, but at least he had a good life and contributed a lot 
.
This guy was seriously good, but at least he had a good life and contributed a lot .
Hans Bethe
Wideranging physicist who helped to develop the atomic bomb and won the Nobel Prize for his work on stellar and solar energy
HANS BETHE was one of the world’s greatest scientists, unusually highly respected by the scientific community. He made considerable contributions to the development of the atomic bomb and nuclear energy during the Second World War. But he was best known for his work on developing a theory for the production of energy in stars. For this, he was awarded the 1967 Nobel Prize.
Hans Albrecht Bethe was born in 1906 in Strasbourg, Alsace (then in the German Empire), where his father was a distinguished physiologist. The family later moved to Frankfurt, where Bethe went to school at the Gymnasium from 1915 to 1924.
He read physics at Frankfurt before moving to the University of Munich in 1926. There, as a protégé of Arnold Sommerfeld, he took his doctorate in theoretical physics in 1928. His thesis was a study of the passage of electrons through crystals, a fashionable subject since quantum theory had surprisingly predicted that electrons, formerly thought to be particles, could, like light, also behave as waves.
Bethe worked for a year as a physics lecturer at the universities of Frankfurt and Stuttgart (where he worked with P. P. Ewald on X-ray diffraction in crystals), before moving in 1929 to the University of Munich. In the winter of 1932-33, he became an assistant professor at the University of Tübingen.
In January 1933, Hitler became Chancellor of Germany and many Jewish academics lost their jobs, including Bethe. Fearing that worse was to come, he emigrated to England, where he was given a temporary lectureship at Manchester University followed by a fellowship at Bristol University. In early 1935, he moved on to the US, having been appointed an assistant professor at Cornell University, at Ithaca, New York. Apart from a leave of absence during the Second World War between 1942 and 1945, and sabbatical leaves, he was to stay at Cornell for the rest of his working life.
In 1930 he and Sommerfeld wrote a review article on the electron theory of metals. The article was mainly Bethe’s work, and not only described the papers already published in the field but contributed many new ideas. Bethe also studied the problem of how particles travelling at high speeds lost energy as they passed through matter. It was an important problem at the time because the relationship between the energy and the range of (the distance travelled by) a particle was an important tool for measuring the energy of a particle.
Between 1935 and 1938, Bethe worked on the theory of nuclear reactions, predicting the cross-sections of many reactions (the probabilities that particular interactions will take place). This led him to the discovery of the nuclear reactions that provide the energy in the stars. Bethe described his research and experimental results in three articles in the Reviews of Modern Physics, which for many years were essential reading for nuclear physicists.
In his 1939 paper Energy Production in Stars, a classic, he explained where stars get their energy from. He proposed that the energy came from a series of six nuclear reactions, beginning with the reaction of a nucleus of an atom of an isotope of carbon (carbon-12) with a proton (a nucleus of a hydrogen atom), and ending with the production of another carbon-12 nucleus and a nucleus of helium (helium-4). In the process a large amount of energy (27 million electron volts) is released.
The carbon-carbon process is the way in which all stars, including our sun, produce the huge amounts of energy they need. For this work — the first explanation of stellar and solar energy, the origin of the bulk of the energy we use on Earth — Bethe was awarded the Nobel Prize in Physics.
In 1942, during the war, Bethe worked on microwave radar at the Radiation Laboratory at the Massachusetts Institute of Technology; in 1943, he went to work at the Los Alamos Scientific Laboratory in New Mexico, where he worked on the Manhattan Project, America's programme to develop nuclear weapons. Invited by Robert Oppenheimer to work on the project, he was one of the first group of scientists to join it, and he headed the Theoretical Physics Division at Los Alamos.
The success of the atomic bomb project owes a great deal to Bethe. Yet he did not at first want to get involved with it. He did not believe that an atomic bomb was a practical idea. He changed his mind when he saw the primitive nuclear reactor that Enrico Fermi had built on the tennis court at Chicago University. He was, in any case, anxious to contribute to the war effort because of his conviction that the Nazis must not be allowed to win the war.
Three nuclear weapons were fabricated at Los Alamos during the war. One was tested in the desert near Alamogordo, New Mexico, on July 16, 1945 (the Trinity test); one was exploded over Hiroshima on August 6, 1945; and the third was exploded over Nagasaki on August 9, 1945. Together the explosions over the two Japanese cities killed about 250,000 people.
Bethe watched the Trinity nuclear test. He said of it: “This was a necessary test for us. We did not know whether the device we had invented, designed, and built would explode. Like others who had worked on the atomic bomb, I was exhilarated by our success — and terrified by the event.” After the war, he became a strong advocate of nuclear disarmament.
In 1947 Bethe, back at Cornell, was the first to explain the Lamb-shift, a small difference in energy levels in the hydrogen atom that led to the modern development of an esoteric new subject called quantum electrodynamics. This achievement is another example of the extraordinary range of Bethe’s accomplishments.
On September 23, 1949, the Soviet Union tested its first nuclear weapon. Like many others, Bethe was surprised that the Soviets were able to do so only four years after the Americans had done. Soon after the Soviet test, Edward Teller, an old friend of Bethe, visited him and tried to persuade him to go back to Los Alamos to work on the development of the hydrogen (H-) bomb or thermonuclear weapon (called the “super bomb” by Teller). Teller argued that the Americans needed the H-bomb to maintain their nuclear superiority over the Soviets.
Bethe thought long and hard about the H-bomb, but decided not to be involved in its development. He came to the conclusion that a war fought with H-bombs would be so destructive that it would leave a world not worth preserving. Although Bethe returned to Los Alamos as a consultant from time to time, he did not change his mind about the development of thermonuclear weapons and argued strongly for the end of the nuclear arms race and for nuclear disarmament.
After leaving Los Alamos, Bethe became involved in the Klaus Fuchs spy case. On January 27, 1950, Fuchs, a British scientist who had worked with Bethe at Los Alamos, confessed to being a Soviet spy. He was tried at the Old Bailey and found guilty on March 1, 1950. Bethe had known Fuchs since 1934, when he met him at Bristol University, and supervised his work in the Theoretical Division from 1944 to 1946. The two men became friends. Bethe regarded Fuchs as an extremely brilliant theoretical physicist without whose contribution the atomic bomb would not have been completed as soon as it was. Bethe had no reason to suspect that Fuchs was spying for the Soviets or even to consider him pro-Soviet. Bethe was very shocked by the arrest of Fuchs, whom he regarded as absolutely loyal and trustworthy.
Another postwar controversy that Bethe took part in was the notorious hearings, which began on April 12, 1954, in which Robert Oppenheimer, then director of the famous Institute for Advanced Study at Princeton University, was alleged to have been disloyal to the USA, mainly because he opposed the American development of the H-bomb. Found guilty, he was branded a security risk and lost his security clearance. It was an odd reward for a brilliant theoretical physicist and an inspiring leader who, as director of the Los Alamos Laboratory, was responsible for the development of the America's atom bomb.
Bethe had a very high opinion of Oppenheimer and testified for him at his hearings. When Oppenheimer died on February 18, 1967, at Princeton, New Jersey, Bethe said: “It was as if an older brother had died.”
As a member of President Eisenhower's Science Advisory Committee between 1956 and 1959, Bethe was involved in the negotiation with the Soviet Union of a treaty banning the testing of nuclear weapons. He continued to argue strongly for a ban on nuclear testing but it was not until September 24, 1996, that a comprehensive test ban treaty was opened for signature. In February 1997, Bethe, then 90 years old, wrote to President Clinton, urging him to stop all tests of nuclear weapons, and also not to sponsor computer simulation of nuclear explosions “or even creative thought designed to produce new categories of nuclear weapons”.
Two years earlier he had written an open letter to all scientists in all countries saying, as one of the few remaining senior scientists on the Manhattan project still alive: “I call on all scientists in all countries to cease and desist from work creating, developing, improving and manufacturing further nuclear weapons; and, for that matter, other weapons of potential mass destruction such as chemical and biological weapons.”
During decades of pure research Bethe and his co-workers made fundamental contributions to more subjects than can be listed here, among them, in addition to those already mentioned, was: solid-state theory; the theory of metals; and a theory of order and disorder in alloys. He became one of the world’s most prominent physicists and scholars, highly respected for his extraordinary achievements and for his great moral integrity. In the words of a former colleague: “He was the last survivor of the golden age of nuclear physics.”
Bethe shone as a solver of tangible problems, rather than abstract ones, at a time when the individual scientist was able to make a fundamental contribution. He was one of the old school of physicists. In more recent times, the physicist solving problems in his laboratory has given way to large groups working on big and very expensive equipment in large international centres, such as CERN in Switzerland. Research papers in physics journals now have a long string of authors rather than one or two.
Bethe’s interest in the nuclear physics of stars continued in his retirement. He studied how stars explode, and he worked with other physicists on why so few of the theoretically predicted neutrinos emitted from the sun reach the Earth. These mysterious and elusive particles interact so weakly with matter that they are extremely difficult to detect.
Bethe was particularly fond of walking, in the mountains or in the countryside. He had a serious manner but also a fine sense of humour, a combination that delighted his students, friends and colleagues. He had numerous honours, among them the Nobel Prize, the Enrico Fermi prize and Foreign Membership of the British Royal Society.
In 1939, Bethe married Rose Ewald, the daughter of the researcher he worked with at Stuttgart in 1929. She survives him with their son and daughter.
Hans Bethe, physicist, was born on July 2, 1906. He died on March 6, 2005, aged 98.
Wideranging physicist who helped to develop the atomic bomb and won the Nobel Prize for his work on stellar and solar energy
HANS BETHE was one of the world’s greatest scientists, unusually highly respected by the scientific community. He made considerable contributions to the development of the atomic bomb and nuclear energy during the Second World War. But he was best known for his work on developing a theory for the production of energy in stars. For this, he was awarded the 1967 Nobel Prize.
Hans Albrecht Bethe was born in 1906 in Strasbourg, Alsace (then in the German Empire), where his father was a distinguished physiologist. The family later moved to Frankfurt, where Bethe went to school at the Gymnasium from 1915 to 1924.
He read physics at Frankfurt before moving to the University of Munich in 1926. There, as a protégé of Arnold Sommerfeld, he took his doctorate in theoretical physics in 1928. His thesis was a study of the passage of electrons through crystals, a fashionable subject since quantum theory had surprisingly predicted that electrons, formerly thought to be particles, could, like light, also behave as waves.
Bethe worked for a year as a physics lecturer at the universities of Frankfurt and Stuttgart (where he worked with P. P. Ewald on X-ray diffraction in crystals), before moving in 1929 to the University of Munich. In the winter of 1932-33, he became an assistant professor at the University of Tübingen.
In January 1933, Hitler became Chancellor of Germany and many Jewish academics lost their jobs, including Bethe. Fearing that worse was to come, he emigrated to England, where he was given a temporary lectureship at Manchester University followed by a fellowship at Bristol University. In early 1935, he moved on to the US, having been appointed an assistant professor at Cornell University, at Ithaca, New York. Apart from a leave of absence during the Second World War between 1942 and 1945, and sabbatical leaves, he was to stay at Cornell for the rest of his working life.
In 1930 he and Sommerfeld wrote a review article on the electron theory of metals. The article was mainly Bethe’s work, and not only described the papers already published in the field but contributed many new ideas. Bethe also studied the problem of how particles travelling at high speeds lost energy as they passed through matter. It was an important problem at the time because the relationship between the energy and the range of (the distance travelled by) a particle was an important tool for measuring the energy of a particle.
Between 1935 and 1938, Bethe worked on the theory of nuclear reactions, predicting the cross-sections of many reactions (the probabilities that particular interactions will take place). This led him to the discovery of the nuclear reactions that provide the energy in the stars. Bethe described his research and experimental results in three articles in the Reviews of Modern Physics, which for many years were essential reading for nuclear physicists.
In his 1939 paper Energy Production in Stars, a classic, he explained where stars get their energy from. He proposed that the energy came from a series of six nuclear reactions, beginning with the reaction of a nucleus of an atom of an isotope of carbon (carbon-12) with a proton (a nucleus of a hydrogen atom), and ending with the production of another carbon-12 nucleus and a nucleus of helium (helium-4). In the process a large amount of energy (27 million electron volts) is released.
The carbon-carbon process is the way in which all stars, including our sun, produce the huge amounts of energy they need. For this work — the first explanation of stellar and solar energy, the origin of the bulk of the energy we use on Earth — Bethe was awarded the Nobel Prize in Physics.
In 1942, during the war, Bethe worked on microwave radar at the Radiation Laboratory at the Massachusetts Institute of Technology; in 1943, he went to work at the Los Alamos Scientific Laboratory in New Mexico, where he worked on the Manhattan Project, America's programme to develop nuclear weapons. Invited by Robert Oppenheimer to work on the project, he was one of the first group of scientists to join it, and he headed the Theoretical Physics Division at Los Alamos.
The success of the atomic bomb project owes a great deal to Bethe. Yet he did not at first want to get involved with it. He did not believe that an atomic bomb was a practical idea. He changed his mind when he saw the primitive nuclear reactor that Enrico Fermi had built on the tennis court at Chicago University. He was, in any case, anxious to contribute to the war effort because of his conviction that the Nazis must not be allowed to win the war.
Three nuclear weapons were fabricated at Los Alamos during the war. One was tested in the desert near Alamogordo, New Mexico, on July 16, 1945 (the Trinity test); one was exploded over Hiroshima on August 6, 1945; and the third was exploded over Nagasaki on August 9, 1945. Together the explosions over the two Japanese cities killed about 250,000 people.
Bethe watched the Trinity nuclear test. He said of it: “This was a necessary test for us. We did not know whether the device we had invented, designed, and built would explode. Like others who had worked on the atomic bomb, I was exhilarated by our success — and terrified by the event.” After the war, he became a strong advocate of nuclear disarmament.
In 1947 Bethe, back at Cornell, was the first to explain the Lamb-shift, a small difference in energy levels in the hydrogen atom that led to the modern development of an esoteric new subject called quantum electrodynamics. This achievement is another example of the extraordinary range of Bethe’s accomplishments.
On September 23, 1949, the Soviet Union tested its first nuclear weapon. Like many others, Bethe was surprised that the Soviets were able to do so only four years after the Americans had done. Soon after the Soviet test, Edward Teller, an old friend of Bethe, visited him and tried to persuade him to go back to Los Alamos to work on the development of the hydrogen (H-) bomb or thermonuclear weapon (called the “super bomb” by Teller). Teller argued that the Americans needed the H-bomb to maintain their nuclear superiority over the Soviets.
Bethe thought long and hard about the H-bomb, but decided not to be involved in its development. He came to the conclusion that a war fought with H-bombs would be so destructive that it would leave a world not worth preserving. Although Bethe returned to Los Alamos as a consultant from time to time, he did not change his mind about the development of thermonuclear weapons and argued strongly for the end of the nuclear arms race and for nuclear disarmament.
After leaving Los Alamos, Bethe became involved in the Klaus Fuchs spy case. On January 27, 1950, Fuchs, a British scientist who had worked with Bethe at Los Alamos, confessed to being a Soviet spy. He was tried at the Old Bailey and found guilty on March 1, 1950. Bethe had known Fuchs since 1934, when he met him at Bristol University, and supervised his work in the Theoretical Division from 1944 to 1946. The two men became friends. Bethe regarded Fuchs as an extremely brilliant theoretical physicist without whose contribution the atomic bomb would not have been completed as soon as it was. Bethe had no reason to suspect that Fuchs was spying for the Soviets or even to consider him pro-Soviet. Bethe was very shocked by the arrest of Fuchs, whom he regarded as absolutely loyal and trustworthy.
Another postwar controversy that Bethe took part in was the notorious hearings, which began on April 12, 1954, in which Robert Oppenheimer, then director of the famous Institute for Advanced Study at Princeton University, was alleged to have been disloyal to the USA, mainly because he opposed the American development of the H-bomb. Found guilty, he was branded a security risk and lost his security clearance. It was an odd reward for a brilliant theoretical physicist and an inspiring leader who, as director of the Los Alamos Laboratory, was responsible for the development of the America's atom bomb.
Bethe had a very high opinion of Oppenheimer and testified for him at his hearings. When Oppenheimer died on February 18, 1967, at Princeton, New Jersey, Bethe said: “It was as if an older brother had died.”
As a member of President Eisenhower's Science Advisory Committee between 1956 and 1959, Bethe was involved in the negotiation with the Soviet Union of a treaty banning the testing of nuclear weapons. He continued to argue strongly for a ban on nuclear testing but it was not until September 24, 1996, that a comprehensive test ban treaty was opened for signature. In February 1997, Bethe, then 90 years old, wrote to President Clinton, urging him to stop all tests of nuclear weapons, and also not to sponsor computer simulation of nuclear explosions “or even creative thought designed to produce new categories of nuclear weapons”.
Two years earlier he had written an open letter to all scientists in all countries saying, as one of the few remaining senior scientists on the Manhattan project still alive: “I call on all scientists in all countries to cease and desist from work creating, developing, improving and manufacturing further nuclear weapons; and, for that matter, other weapons of potential mass destruction such as chemical and biological weapons.”
During decades of pure research Bethe and his co-workers made fundamental contributions to more subjects than can be listed here, among them, in addition to those already mentioned, was: solid-state theory; the theory of metals; and a theory of order and disorder in alloys. He became one of the world’s most prominent physicists and scholars, highly respected for his extraordinary achievements and for his great moral integrity. In the words of a former colleague: “He was the last survivor of the golden age of nuclear physics.”
Bethe shone as a solver of tangible problems, rather than abstract ones, at a time when the individual scientist was able to make a fundamental contribution. He was one of the old school of physicists. In more recent times, the physicist solving problems in his laboratory has given way to large groups working on big and very expensive equipment in large international centres, such as CERN in Switzerland. Research papers in physics journals now have a long string of authors rather than one or two.
Bethe’s interest in the nuclear physics of stars continued in his retirement. He studied how stars explode, and he worked with other physicists on why so few of the theoretically predicted neutrinos emitted from the sun reach the Earth. These mysterious and elusive particles interact so weakly with matter that they are extremely difficult to detect.
Bethe was particularly fond of walking, in the mountains or in the countryside. He had a serious manner but also a fine sense of humour, a combination that delighted his students, friends and colleagues. He had numerous honours, among them the Nobel Prize, the Enrico Fermi prize and Foreign Membership of the British Royal Society.
In 1939, Bethe married Rose Ewald, the daughter of the researcher he worked with at Stuttgart in 1929. She survives him with their son and daughter.
Hans Bethe, physicist, was born on July 2, 1906. He died on March 6, 2005, aged 98.
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