Iosef S. Shklovskii, a seminal and prolific Soviet astrophysicist best known in this country for his speculations on extraterrestrial life, died Sunday in Moscow at 68.
Although he was Jewish and an outspoken critic of the Soviet system, Shklovskii's contributions to astronomy and to the Soviet unmanned planetary space program protected him from reprisals by Russian authorities. He was a gifted teacher whose students included today's leaders of the Soviet scientific space program.
"He made absolutely essential and major contributions to astrophysics over an extremely wide range of subjects," Carl Sagan, the Cornell University astronomer who collaborated with Shklovskii on a book on extraterrestrial intelligence, said Wednesday by telephone from his office in Ithaca, N.Y. Shklovskii made basic discoveries in the understanding of neutron stars, quasars, exploding galaxies and planetary physics, and he was the first to propose an explanation for the non-thermal radiation from the Crab Nebula.
He also led the Soviet Union's move into the search for extraterrestrial intelligence, a subject on which he wrote a book in 1962. In 1966 Shklovskii's manuscript was translated into English, and Sagan wrote extensive annotations for it. The resulting collaborative effort was published as "Intelligent Life in the Universe," a book that is still in print and widely used as a textbook for general introduction to science.
Book Cites Odds
In the book, the first comprehensive discussion of the subject, Shklovskii and Sagan argued that even if the chance of each individual event leading to the creation of life is very small, there are so many stars and so many planets that the odds favor the existence of thousands of other planets with intelligent life. They argued further that the present moment is the first time in human history that mankind has the technology to find out, and they proposed imaginative ways for conducting the search.
Because the argument demands discussion of physics, chemistry, astronomy, biology and the origin of life, among other topics, the book wound up being a concise and highly readable introduction to these subjects, which helped make it a popular textbook.
It was an unusual collaboration between two authors who had never met when the book was published. In the introduction, Sagan quoted a letter from Shklovskii in which the Russian told his co-author: "The probability of our meeting is . . . smaller than the probability of a visit to the Earth by an extraterrestrial cosmonaut." At the time, Shklovskii was being kept under wraps in the Soviet Union, but it was never clear whether that was the result of his criticisms of the Russian state or his involvement in sensitive military work. "He spoke to me and to many others about anti-Semitism in the Soviet Union," Sagan said.
In any case, shortly after the book came out in English, Shklovskii was allowed to travel outside Russia, and he and Sagan met in New York. Based on his letter, Sagan recalled: "When we actually met, I told him I was now confident that we would find extraterrestrial intelligence.
"He was primarily a main line and superb theoretical astrophysicist," Sagan said Wednesday. "If he had never thought about this subject (of extraterrestrial life), his contributions would be extremely lasting."
Shklovskii was born in Glukhov in the Ukraine on July 1, 1916, and he graduated from Moscow University in 1938. He was associated with the Shternberg Astronomical Institute and the Institute of Space Research in Moscow. He received the Lenin Prize in 1960 and was a corresponding member of the Soviet Academy of Sciences. The cause of his death was not announced.