His life nearly spanning the 20th century and productively extending into the 21st, Hans Bethe (1906-2005), née Hans Albrecht Bethe, earned a position in the highest rank of pioneer physicists of the 20th century.    He devoted much of intellectual energy in helping develop the theory of atomic nuclei and of nuclear reactions. That work led him to discover the reactions in the sun that generate and deliver energy to its surrounding, including Earth, for which discovery, and for his discovery of the different set of nuclear reactions that generates the radiant energy of stars more massive than the sun, and for his many contributions to the theory of nuclear reactions, he received the Nobel Prize in Physics in 1967, as sole recipient. He concluded his Nobel Lecture as follows:
If all this is true, stars have a life cycle much like animals. They get born, they grow, they go through a definite internal development, and finally they die, to give back the material of which they are made so that new stars may live.
During World War II, he headed the theoretical physics division at Los Alamos, New Mexico, where he contributed to the development of the first atomic bomb.
Life and work
Hans Bethe joined the ranks of humanity in Strasbourg, in the then German (now French) Alsace-Lorraine region. He was born on July 2, 1906, and died in Ithaca, New York State, on March 6, 2005, leaving humanity with a invaluable legacy of knowledge about the nature of the universe and of humanity itself. He spent his boyhood growing up in an educated family, his father, Albrecht, was a professor of physiology, his mother, Anna, was Jewish, and a daughter of a university professor. Hans received private tutorship and showed precocity in mathematics. He attended Goethe Gymnasium in Frankfurt, when his family moved there in 1915, his father having received an invitation to establish a department of physiology at the university there. At age 18 years (1924), he began undergraduate studies at the University of Frankfurt, where he remained for two years.
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- Biography: Hans Bethe, The Nobel Prize in Physics 1967.
- Excerpt: Bethe's main work is concerned with the theory of atomic nuclei. Together with Peierls, he developed a theory of the deuteron in 1934 which he extended in 1949. He resolved some contradictions in the nuclear mass scale in 1935. He studied the theory of nuclear reactions in 1935-1938, predicting many reaction cross sections. In connection with this work, he developed Bohr's theory of the compound nucleus in a more quantitative fashion. This work and also the existing knowledge on nuclear theory and experimental results, was summarized in three articles in the Reviews of Modern Physics which for many years served as a textbook for nuclear physicists.
- Biography from Los Alamos National Laboratory
- Excerpt: Over the winter of 1942-43, Project Y came together at Los Alamos under the leadership of General Leslie R. Groves and Oppenheimer. Hans Bethe emerged as a primary candidate to work at the Los Alamos project. Edward Teller, his old friend and Berkeley summer colleague, urged an ambivalent Bethe to join the project. Bethe finally gave in, and Oppenheimer made him chief of the Theoretical Division, a position Teller sorely coveted. This slight marked the beginning of a feud that would last for decades.
- About Hans Bethe. From website: Quantum Physics Made Relatively Simple: Personal and Historical Perspectives of Hans Bethe 2004. Last accessed: December 30, 2008.
- Excerpt: In the decade following World War II, Bethe and Feynman and their students played a central role in developing quantum electrodynamics, work for which Feynman shared the Nobel Prize. From 1945, until his retirement from the Cornell faculty in 1975, Bethe trained and inspired a large number of graduate students. Many have gone on to become internationally known scientists, among them Freeman Dyson. Bethe and his co-workers published important work across the whole spectrum of physics. Even today, in his nineties, his unique mastery of such diverse subjects as thermonuclear processes, shock waves and neutrino reactions have kept Bethe at the forefront of research in astrophysics.
- Sun: Internal structure - Energy generation and transport (2008). In Encyclopædia Britannica. Retrieved December 30, 2008, from Encyclopædia Britannica Online. Full-text online free.
- Hans Bethe. Energy Production in Stars The Nobel Prize in Physics 1967. Nobel Lecture, December 11, 1967.
- Excerpt: From time immemorial people must have been curious to know what keeps the sun shining. The first scientific attempt at an explanation was by Helmholtz about one hundred years ago, and was based on the force most familiar to physicists at the time, gravitation....if gravitation supplies the energy, there is enough energy available to supply the radiation for about 1015 sec which is about 30 million years....This was long enough for nineteenth century physicists, and certainly a great deal longer than man’s recorded history. It was not long enough for the biologists of the time. Darwin’s theory of evolution had just become popular, and biologists argued with Helmholtz that evolution would require a longer time than 30 million years, and that therefore his energy source for the sun was insufficient. They were right.
- From the Los Alamos National Laboratory
- Bethe's description of his work supervising the theoretical physics division: Supervision of the work of the theoretical division of the Los Alamos Project. The work of the Division in the first year was mostly concerned with the prediction of the critical mass and multiplication rate of a fission bomb....The larger fraction of the effort since Nov. 1943 was devoted to the theoretical study of the hydrodynamics of implosion. From March to June 1944 I had direct charge of the group concerned with implosion hydrodynamics. The emphasis of my own work shifted with that of the division....In 1945 I worked on the theory of the initiator.... and most recently on the hydrodynamics connected with the propagation of radiation in the nuclear explosion....The largest fraction of my time was concerned with the correlation of the work of the division.