Hans Bethe, a scrupulously open-minded Nobel Prize winner who was perhaps the last survivor of the scientific titans who created nuclear physics and nuclear weapons, died March 5 at his home in Ithaca, N.Y., near Cornell University. He was 98.
His wife, Rose, daughter of a famed German university professor, said he died of congestive heart failure.
Hans Bethe at Cornell in 1996. In the background is his famous carbon cycle equation for nuclear energy generation in stars.
Dr. Bethe's Nobel Prize, awarded in 1967, came for work that stirred the imagination: He explained with pencil and paper how starlight is produced and what makes the sun shine.
What he described in detail in the 1930s were thermonuclear reactions of a kind that would later make possible the hydrogen bomb.
Dr. Bethe, a man viewed as a genius by colleagues and co-workers who were themselves regarded as among the most brilliant figures of their time, was also a principal figure in the development of the atom bomb, which ended World War II.
At Los Alamos, the secret New Mexico laboratory where the A-bomb was designed and built during the war, Dr. Bethe, esteemed for his knowledge and his reliability, was named to head the theoretical division.
After having met him in Europe as a young man, Edward Teller, known as the father of the hydrogen bomb, said Dr. Bethe had "the most comprehensive knowledge of theoretical physics that I had ever encountered."
Among the luminaries of 20th-century physics, Dr. Bethe was acknowledged to be in the front rank, serving as teacher, colleague and friend, and as a beacon in some of the moral confusions that sometimes accompanied their accomplishments.
The celebrated Richard Feynman worked for him at Los Alamos and studied with him at Cornell. Dr. Bethe testified for J. Robert Oppenheimer, who headed the atom bomb project, at Oppenheimer's security hearing; he gave a eulogy at Oppenheimer's 1967 funeral.
A participant in the postwar public debate over weapons policy, he appeared able to take strong stands without alienating his friends on the other side, and without depriving them of credit for their abilities and achievements.
He was widely regarded as the conscience of the nuclear science community.
When he first spoke in favor of limits on bomb testing, his impeccable reputation gave immediate credibility to that position.
He was also considered one of the most persuasive opponents of many of the schemes proposed in the 1980s to provide a shield against nuclear-armed missiles.
Nuclear physics, which was to seize the popular imagination in the second half of the 20th century, was in its infancy in the 1930s, when Dr. Bethe, in a literal sense, wrote the book on it.