Everything about Hans Bethe totally explained
Hans Albrecht Bethe (
July 2 1906 –
March 6,
2005) was a
German-
American physicist, and
Nobel laureate in
physics for his work on the theory of
stellar nucleosynthesis. Bethe also made important contributions to
quantum electrodynamics,
nuclear physics and
particle astrophysics. During
World War II, he was head of the Theoretical Division at the secret
Los Alamos laboratory developing the first
atomic bombs. There he played a key role in calculating the
critical mass of the weapons, and did theoretical work on the
implosion method used in both the
Trinity test and the "
Fat Man" weapon dropped on
Nagasaki,
Japan.
During the early 1950s, Bethe also played an important role in the development of the larger
hydrogen bomb, though he'd originally joined the project with the hope of proving it couldn't be made. Bethe later campaigned together with
Albert Einstein in the
Emergency Committee of Atomic Scientists against
nuclear testing and the
nuclear arms race. He influenced the
White House to sign the
ban of atmospheric nuclear tests in 1963 and the 1972
Anti-Ballistic Missile Treaty,
SALT I. His scientific research never ceased even into the later years of his life. He is one of the few scientists who can claim a major paper in his field every decade of his career, which spanned nearly sixty years.
Freeman Dyson called Bethe the "supreme problem solver of the 20th century."
Early Years
Bethe was born in
Strassburg,
Germany, which since 1919 has been in
France. Although his mother was
Jewish, he was raised in the religion of his father,
Christianity. Bethe studied
physics at
JWG University, Frankfurt, and went on to earn his doctorate from the
University of Munich with supervisor
Arnold Sommerfeld, after which he did postdoctoral stints in
Cambridge and at
Enrico Fermi's laboratory in
Rome. He was influenced by Fermi's simplicity and Sommerfeld's rigor in approaching problems, and these qualities influenced his own later research.
Bethe left Germany in 1933 when the
Nazis came to power and he lost his job at the
University of Tübingen, 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 England, Bethe worked with the theoretician
Rudolf Peierls on a comprehensive theory of the
deuteron. In 1929, Bethe made an important contribution to solid state physics and chemistry, with his formulation of the basic concepts of
crystal field theory. His paper is regarded as the starting point for all serious later discussions of the topic. In 1930, he devised a formula for the energy loss of swift charged particles in matter called the
Bethe formula, which is now as important as it was then.
In 1935 Bethe moved to the
United States, and joined the faculty at
Cornell University, a position which he occupied throughout his career. During 1948-1949 he was a Visiting Professor at
Columbia University. At Cornell, Bethe became known as one of the leading theoretical physicists of his generation, and along with upcoming physicists such as
cyclotron pioneer
Milton Stanley Livingston, and later, after the war, experimentalist
Robert R. Wilson and theoretician
Robert Bacher, put Cornell on the world physics map. Together with
Robert Bacher and Livingston, Bethe published a series of three articles which summarized most of what was known on the subject of nuclear physics 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 this account, he also continued where others left off, filling in gaps from the older literature. From 1935-1938, he studied
nuclear reactions and reaction
cross sections,
carbon-oxygen-nitrogen cycle, leading to his important contribution to
stellar nucleosynthesis. This research was later useful to Bethe in more quantitatively developing
Niels Bohr's
theory of the compound nucleus.
Bethe became a
naturalized citizen of the United States in 1941. He was an honorary member of the
International Academy of Science.
Manhattan Project
When the war began, Bethe wanted to contribute to the war effort. Following the advice of the
Caltech aerodynamicist
Theodore von Karman, Bethe collaborated with his friend
Edward Teller, then at
George Washington University, on a theory of shock waves which are generated by the passage of a projectile through a gas. This work was later useful to researchers investigating
missile reentry. Bethe also worked on a theory of armor penetration, which was immediately classified by the Army, making it inaccessible to Bethe, who wasn't an American citizen at the time.
During the summer of 1942 he served as part of a special session at the
University of California, Berkeley at the invitation of
Robert Oppenheimer, which outlined the first designs for the
atomic bomb. Initially, Bethe was skeptical of the possibility of making a nuclear weapon from uranium. In the late 1930s, he wrote a theoretical paper arguing against fission, but was convinced by Teller to join the Manhattan Project. When Oppenheimer was put in charge of forming a secret weapons design laboratory,
Los Alamos, he appointed Bethe Director of the Theoretical Division, a move that irked Teller, who had coveted the job for himself.
Bethe's work at Los Alamos included calculating the
critical mass of
uranium-235 and the multiplication of
nuclear fission in an exploding atomic bomb. Along with
Richard Feynman, he developed a formula for calculating the explosive yield of the bomb. After November 1943, when the laboratory had been reoriented to solve the
implosion problem of the
plutonium bomb, Bethe spent much of his time studying the hydrodynamic aspects of implosion, a job which he continued into 1944. In 1945, his work concerned working out the workings of the
neutron initiator, and later on radiation propagation from an exploding atomic bomb.
During the project,
Klaus Fuchs, who was leaking nuclear secrets to the Russians, was also in Bethe's division (often doing work which had originally been assigned to Teller). Like everyone else, Bethe had no knowledge that Fuchs was a spy.
When the first implosion atomic bomb was detonated in the New Mexico desert on July 16, 1945, at the
Trinity test, Bethe's immediate concern was for its efficient operation, and not its moral implications and is reported to have commented: "I am not a philosopher."
Hydrogen bomb
After the war, Bethe argued that a crash project for the
hydrogen bomb shouldn't be attempted, though after President
Harry 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'd see the project through to its end, in Bethe's account he personally hoped that it would be impossible to create the hydrogen bomb. He would later remark in 1968 on the apparent contradiction in his stance, having first opposed the development of the weapon and later helping to create it:
Teller-Ulam priority dispute, Bethe later said that:
At the time of his death, he was the John Wendell Anderson Professor of Physics Emeritus at
Cornell University. He also was, reaching the age of 98, the second-oldest Nobel laureate ever. Since his death, Cornell has announced that the third of five new
residential colleges, each of which will be named after a distinguished former member of the Cornell faculty, will be named the
Hans Bethe House. Bethe with his wife Rose, had two children, Henry and Monica.
Honours and awards
Awards
Further Information
Get more info on 'Hans Bethe'.
|
External Link Exchanges
Do you know how hard it is to get a link from a large encyclopaedia? Well we're different and will prove it. To get a link from us just add the following HTML to your site on a relevant page:
<a href="http://hans_bethe.totallyexplained.com">Hans Bethe Totally Explained</a>
Then simply click through this link from your web page. Our crawlers will verify your link, extract the title of your web page and instantly add a link back to it. If you like you can remove the words Totally Explained and embed the link in article text.
As long as your link remains in place, we'll keep our link to you right here. Please play fair - our crawlers are watching. Your site must be closely related to this one's topic. Any kind of spamming, dubious practises or removing the link will result in your link from us being dropped and, potentially, your whole site being banned. |
