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Shklovskii, Iosif Samuilovich


(b. Glukhov, Ukraine (then Russia), 1 July 1916; d. Moscow, USSR, 3 March 1985), theoretical astrophysics.

Shklovskii’s major scientific achievement was to show that both the radio and optical emissions from the Crab Nebula can be explained as synchrotron radiation. He is also known for his book Intelligent Life in the Universe(1966), co-authored with Carl Sagan. Shklovskii organized the radio astronomy department at Moscow University and later served as chief of the astrophysics department of the new Institute of Space Research in Moscow, having overcome many of the obstacles confronting Soviet scientists of his generation.

Youth The son of a rabbi, Shklovskii (Josif Shklovsky is an alternative transliteration) grew up in a traditional Jewish environment in Glukhov, a small Ukrainian town. He regarded himself as an October Revolution baby, fortunate to have survived famine during World War I, the October Revolution of 1917, and the Russian Civil War from 1918 to 1920. His family was desperately poor, especially after his father died. Conditions worsened with the forced collectivization of agriculture beginning in 1929, and in 1930 Shklovskii’s family migrated to Kazakhstan. Leaving behind his Jewish childhood, Shklovskii became, he later said, a modern Soviet youth. Though henceforth never a practicing Jew, on travel outside the Soviet Union he would visit Jewish memorials.

In 1931 Shklovskii graduated from secondary school in Akmolinsk (now Astana). Students then attended seven years of school before entering a factory-plant school for further education and training as workers. Shklovskii worked as a foreman in railroad construction. In 1933 he began studies in physics and mathematics at the Far-Eastern State University in Vladivostok, and in 1935 transferred to the physics department of the Moscow State University. Open competition in entrance examinations had begun two years earlier, though preference was still given to those with better biographical particulars. Students lived in wooden barracks on the northern edge of Moscow, an hour by tram when slowed by winter snow and ice. Trenches served as latrines, with frozen stalagmites of repulsive composition. Nonetheless, many of the students were carefree. They ate meat at the beginnings of months, and bread, sugar, and hot water when their monthly stipends ran low.

Not so pleasant were what Shklovskii later called in his autobiographical Five Billion Vodka Bottles to the Moon: Tales of a Soviet Scientist (1991) the “mass psychoses” that “rolled over us like tidal waves.” A roommate envious of Shklovskii’s easy academic success denounced him for Trotskyite agitation, but the matter was quickly dropped. More worrisome was a summons to the Lubyanka. There Shklovskii was asked about another student, answered that he knew nothing incriminating, and was dismissed, though not before seeing a man escorted with his hands behind his back and blood streaming down his face.

Back in the student quarter, Shklovskii was making an impression. He challenged history students to present him with ten questions, all of which he would answer, while their champion would answer only one of Shklovskii’s ten history questions. He later claimed to have won decisively all the monthly tournaments; he focused his reading in history rather than physics during this period. Shklovskii was also an artist, having begun drawing at the age of three with a piece of chalk, or a brick, or anything else at hand, and he drew wonderful portraits of fellow students.

Shternberg Astronomical Institute Upon graduation in 1938, Shklovskii received a two-year work assignment to swamp forests in Siberia. With a wife and a newborn daughter, he was reluctant to go. The physics department would not admit him for graduate work, and he didn't like the atmosphere at the Physical Chemistry Institute. He saw a notice in a newspaper about the P. K. Shternberg State Astronomical Institute, the astronomy department of Moscow University. Astrophysics was becoming recognized as an important branch of astronomy, and the Moscow astronomy department, eager to bring in physics students, admitted Shklovskii.

The department survived the great purge of the late 1930s, in contrast to the Pulkovo Observatory, outside Leningrad (now St. Petersburg). There a disgruntled graduate student, after failing an examination, denounced his adviser for possessing foreign scientific correspondence. Arrested and beaten, the professor confessed to being the leader of a Fascist-Trotskyite-Zinovievite terrorist organization in league with German intelligence to establish a fascist dictatorship in the Soviet Union, and also named fellow conspirators. In the chain reaction and conflagration that followed, approximately 80 percent of the Pulkovo staff were repressed and a majority perished. In the 1950s the Office of the Military Procurator, finding no evidence of any crimes having been committed, would fully rehabilitate the victims, in most cases posthumously.

At Shternberg a student also failed an examination and denounced his advisor, as a nonproletarian scientist blocking the entry of workers into science. The astronomer was also accused of collaborating with an arrested enemy of the people: the director of the Pulkovo Observatory. Other students in the red graduate student organization rebuffed the provocation, the complaining student was expelled, and no one was repressed. (Many years later, during the Cold War, Soviet scientists dared send only published papers and standard new year’s greetings to foreign colleagues.)

Following the German invasion in 1941, Shklovskii lived briefly in one of a score of freight cars very slowly evacuating students to Ashkhabad. He lent Andrei Sakharov, a fellow inhabitant, a physics book. Once in Central Asia, many of the students were sent to military schools and then as junior lieutenants to the front, where fewer than 5 percent would survive. Myopia disqualified Shklovskii from military service. He was in Ashkhabad for ten months, and then Sverdlovsk, where he rejoined the Astronomical Institute in September 1942.

In April 1943 Shklovskii and the institute were back in Moscow. He wrote his candidate thesis (nearly equivalent to a PhD thesis in the West) in 1944, on the concept of the electron temperature in astronomy, and his doctoral thesis (usually by someone over thirty years old and the author of dozens of papers; and conferring the right to hold a professor’s post) in 1949, on the physics of the solar corona, including its confinement by magnetic fields, its extraordinarily high temperature, of more than a million Kelvin, and its radio emission. Holding the only doctorate in his subfaculty at the Astronomical Institute, Shklovskii was nicknamed the Doctor.

In the summer of 1946, Shklovskii learned from a fragment of a review report he heard by accident at a scientific meeting, that during the war the British Royal Air Force had detected radio emissions from the Sun. Already working for the past three years on the physics of the solar corona, Shklovskii realized immediately that the emission must be from the corona. Another Soviet scientist, Vitaly Ginzburg, came to the same realization independently, from his work on a project to bounce radio waves off the Sun and the Moon. The leader of this project, a favorite of Joseph Stalin, obtained (out of a country ravished by war) funding for a complicated and expensive solar eclipse expedition to Brazil in 1947. Shklovskii was assigned to the optical part of the expedition, whose efforts were frustrated by cloudy conditions. But radio observations found the radio diameter of the Sun larger than its optical diameter, confirming Shklovskii’s hypothesis.

Accompanying the expedition was an individual assigned to ensure ideological restraint by the real scientists. At a public celebration, Shklovskii induced this comrade to sing a particular Russian song, some of whose words sounded like obscene Portuguese words. The women walked out while the men yelled and applauded. Shklovskii was not permitted to travel abroad again for eighteen years, though probably more as a matter of general Soviet policy restricting contact with the rest of the world than in reprisal for his Brazilian linguistic escapade. The time in Brazil, contrasted with a poverty-stricken boyhood and wartime privations, was the happiest period of Shklovskii’s life.

In 1951 Shklovskii and other Jews were dismissed from Shternberg. He was reinstated two weeks later by the rector of the university, who appreciated Shklovskii as a star in the Soviet astronomical firmament. Still, Shklovskii was a Jew. In 1953 Jewish doctors at a Kremlin hospital were accused of poisoning Soviet elite; the pending pogrom was forestalled only by Stalin’s death.

Crab Nebula In 1953 Shklovskii made his most significant scientific achievement. Waiting for the tram to the student barracks, he was thinking about the Crab Nebula and its emissions. In the radio range they were too strong to be an extension of thermal optical emissions. Why not, he wondered, instead try to explain the optical radiation as an extension of nonthermal radio emissions. He hypothesized that the light emitted by the Crab Nebula was synchrotron radiation from charged particles spiraling at nearly the speed of light through a large and well-ordered magnetic field, and then during the 45-minute trolley ride he did in his head the entire theoretical calculation establishing that, rather than a dense plasma, only a small number of relativistic electrons of sufficiently high energy could produce optical radiation of the observed intensity. Then he wrote it up, with no revisions.

The impossibility of reconciling the optical and radio emissions as thermal in origin was discussed by American astronomers Jesse Greenstein and Rudolph Minkowski in a 1953 paper in the Astrophysical Journal, but seemingly this paper was not known to Shklovskii; he did not cite it in his paper. He did cite Minkowski’s 1942 paper on the optical emission and a 1949 paper reporting that that the radio emission was a thousand times more intense than the optical emission. Also, in 1950 the Swedish physicist Hannes Alfrén had proposed the general idea of synchrotron radiation. Shklovskii’s breakthrough achievement was to link these phenomena, quantitatively as well as suggestively; he connected the dots. It was a major step in the transformation of astronomy from optical to all-wave studies and to high-energy astrophysics with magnetic fields and high-energy particles. Ginzburg had also thought to apply synchrotron radiation to astronomy, and would later claim priority.

Shklovskii did not note in his paper that, if the emissions from the Crab Nebula were synchrotron radiation, they must be polarized. Other Soviet astronomers realized this and quickly reported finding polarization. Few astronomers in the west believed the initial claims, but Jan Oort in the Netherlands convinced his friend Greenstein to use the Mount Palomar telescope, the largest optical telescope in the world, to search for polarization, which he found. Continuing this line of research, Shklovskii suggested in a paper for a 1955 symposium that emission from the galaxy M 87 (NGC 4486) likely was similar to that from the Crab Nebula. A note added in proof in 1957 reported confirmation. Another test of Shklovskii’s theory occurred in the 1960s, when he predicted that a young supernova remnant with its rapid expansion would have a correspondingly rapid decrease in the strength of its magnetic field and also its synchrotron radiation. This was confirmed within a year.

Honors and Promotions In 1954 Shklovskii was appointed a professor and he organized a radio astronomy department. The previous year he had given a series of lectures on radio astronomy. He now moved out of the single room in the student barracks which he and his family had occupied for nineteen years, and into a relatively luxurious three-room apartment in another Moscow University building; and his son was admitted to the university.

Shklovskii received the Order of Lenin, his country’s highest civil order, in 1960. The Soviet Union was ready in 1959 to send a rocket to the Moon, after the Americans had failed four times in 1958, but had no radio telescope capable of tracking a lunar rocket. Shklovskii proposed turning the rocket into an “artificial comet” by vaporizing on board several kilograms of sodium, which would scatter the yellow rays of the Sun, resulting in a cloud of resonance fluorescence bright enough to be observed optically. The successful Lunik 2 was so observed.

Not until 1966, however, was this outspoken Jew elected to the Soviet Academy of Sciences, as a corresponding member, on his fifth try, and he was never elected a full member, failing in some dozen elections. Corresponding members of the Soviet Academy of Sciences received, in addition to regular salaries, a 250 ruble monthly stipend, and full members 500 rubles, when the monthly salary of a young scientist was 150 to 200 rubles and heads of departments were paid 500 rubles. Membership could be the difference between life and death; in 1967 Shklovskii was treated in the academy’s hospital for a heart attack.

Shklovskii was highly honored abroad. He was elected a foreign member of the Royal Astronomical Society in 1964, of the American Academy of Arts and Sciences in 1966, an honorary member of the U.S. National Academy of Sciences in 1972, and also a foreign member of the American Astronomical Society and the Royal Astronomical Society of Canada. He received the Jansky Prize of the U.S. National Radio Astronomy Observatory in 1968 and the prestigious Bruce Medal of the Astronomical Society of the Pacific in 1972. And asteroid 2849 Shklovskij [sic] is named in his honor.

Travel and Publications Abroad After the Brazil expedition in 1947, Shklovskii applied for travel visas dozens of times, and in 1965 in the university dining hall talking to someone he hardly knew, Shklovskii remarked that he was busy with his hobby of hopelessly filling out travel forms. The person worked in the foreign section of the university, and three days later Shklovskii was on a train to Prague, having accepted a repeated invitation to give a talk there. He had attained, so he later recounted in his Five Billion Vodka Bottles, the “first cosmic velocity.” A year later, with his election to the Soviet Academy of Sciences, he attained the “second cosmic velocity,” which made possible trips to capitalist countries. In 1967 he traveled to the United States and France, and Prague again, for the International Astronomical Union meeting there. He impressed foreign colleagues as a very smart, quick-thinking, talkative, and amusing guy, with a sound knowledge of astronomy and astrophysics. For the meeting in Paris, his visa was so late that he only made the last day of the conference. He stayed on, wandering the streets and living on not much more than a kilo of bread a day until his pitifully meager travel funds and his visa expired a week later. At the conference in the United States, he mentioned an interest in visiting several observatories, and his hosts immediately supplied him with airplane tickets and money; Edward Teller was among those eager to talk with Shklovskii. In 1973, after forty Soviet academicians signed a document condemning Andrei Sakharov, Shklovskii signed a letter in Sakharov’s defense, and lost his travel privileges. Foreign colleagues were informed that he was ill. When restrictions on his travel were later eased, Shklovskii explained that he had had diabetes from too much Sakharov (the Russian word for sugar is sakhar).

Only he who does nothing makes no mistakes, Shklovskii often said. Measurements of the position of Mars’s moon Phobos suggested that it was spiraling inward toward Mars. In 1959 Shklovskii hypothesized that friction with the outer atmosphere of Mars was producing a drag on the satellite. However, to explain the inward spiraling quantitatively, Phobos had to be hollow. Perhaps it was an artificial space station launched long ago by a now-extinct Martian civilization. The resulting furor was great fun for Shklovskii and a needed distraction from his mother’s death. (Later studies have found the acceleration to be only half as much, and explainable with a solid satellite affected by forces due to tides it raises in Mars. Phobos will crash into Mars in 40 million years.) Carl Sagan, recognizing a fellow spirit, mailed Shklovskii a preprint of his paper on direct contact among galactic civilizations by relativistic interstellar space flight.

Shklovskii next wrote a book on the possible existence of life elsewhere in the universe. Reasoning that censors would not have time to do much in the rush to meet a deadline set by authorities, he had volunteered at a meeting of Soviet space scientists to write a book to celebrate the fifth anniversary of Sputnik the following year. (Actually, he was on safe ideological ground, in as much as members of the Soviet Institute of Astrobotany had concluded that the existence of extraterrestrial life was required by dialectical materialism, and its absence would be clear disproof of the philosophical basis of communism.)

Shklovskii’s book sold out fifty thousand copies in a few hours; went through five editions in his lifetime; a sixth, posthumously, in 1987; and many translations, including one into Braille. Sagan, now on the board of a new book publisher hoping to profit from public interest in science fueled by Sputnik, wanted to reprint Shklovskii’s book in English. Shklovskii agreed, and invited Sagan to add material. Shklovskii thought his invitation applied to biological issues, on which Sagan was more knowledgeable; Sagan added as he saw fit. His travel still restricted, Shklovskii wrote to Sagan that “The probability of our meeting [to cooperate on the book] is unlikely to be smaller than the probability of a visit to the Earth by an extraterrestrial cosmonaut” (Davidson, 1999, p. 150). The resulting book, Intelligent Life in the Universe, appeared in 1966. To Shklovskii’s surprise, it contained more than twice as many words as he had written, not just on biology, and Sagan’s name on the title page as coauthor. At least their respective contributions were delineated. Absent any U.S.-Soviet copyright convention then, Shklovskii received only a token one thousand dollars from the publisher and no share of Sagan’s royalties. The first edition was twenty-five thousand copies in hardback, and a paperback edition appeared in the same year. In Sagan’s 1985 novel Contact, the Russian scientist Vaygay is modeled after Shklovskii, including the episode of the Russian scientist picking up a campaign button in Berkeley with the slogan “Pray for Sex” and commenting that it only offended for one reason in the United States, but for two reasons in his country.

In 1965 Shklovskii joined the newly formed Institute of Space Research in Moscow, and from 1972 until his death in 1985 he was chief of its astrophysics department. He trained some thirty graduate students, and directed the first successful Soviet astrophysical experiments in space. In 1967 he hypothesized that x-ray stars are close binary systems, including an accreting neutron star. Near the end of his life, Shklovskii despaired of success in the search for extraterrestrial intelligence. If there were many other civilizations, some of them would be more advanced than ours, and if so, why had not they contacted us yet? Shklovskii observed that he was the only male of his high school graduating class to survive World War II, and in the subsequent Cold War with its doctrine of mutually assured destruction he perhaps came to worry that intelligent civilizations tend to self-destruct. Surgery for a blood clot in his leg released another blood clot to his brain, and Shklovskii died of a stroke on 3 March 1985.


For additional scientific papers by Shklovskii see the Web site for Bruce Medalists of the Astronomical Society of the Pacific:


“O prirode svecheniia krabovidnai tumannosti.” Doklady Akademii Nauk SSSR 90(1953): 983–986. Shklovskii’s most significant scientific paper. English translation with commentary: “The Nature of the Crab Nebula’s Optical Emission.” In A Source Book in Astronomy and Astrophysics, 1900–1975, edited by Kenneth R. Lang and Owen Gingerich. Cambridge, MA: Harvard University Press, 1979.

“On the Nature of Planetary Nebulae.” In Non-Stable Stars, edited by George H. Herbig. International Astronomical Union Symposium, no. 3. Cambridge, U.K.: Cambridge University Press, 1957.”

On the Nature of the Emission from the Galaxy NGC4486.” In Radio Astronomy, edited by H. C. van de Hulst. International Astronomical Union Symposium, no. 4. Cambridge, U.K.: Cambridge University Press, 1957.

“Optical Emission from the Crab Nebula in the Continuous Spectrum.” In Radio Astronomy, edited by H. C. van de Hulst. International Astronomical Union Symposium, no. 4. Cambridge, U.K.: Cambridge University Press, 1957.

“Some Problems of Meta-Galactic Radio-Emission.” In Radio Astronomy, edited by H. C. van de Hulst. International Astronomical Union Symposium, no. 4. Cambridge, U.K.: Cambridge University Press, 1957.

Cosmic Radio Waves. Translated by Richard B. Rodman and Carlos M. Varsavsky. Cambridge, MA: Harvard University Press, 1960.

Physics of the Solar Corona. International Series of Monographs in Natural Philosophy, vol. 6. Oxford: Pergamon Press, 1965.”

Possible Secular Variation of the Flux and Spectrum of Radio Emissions of Source 1934–63.” Nature206 (1965): 176–177.

Vselennaia, Zhizn, Razum. Moscow: Izd-vo Nauka, 1965.

With Carl Sagan. Intelligent Life in the Universe. Translation by Paula Fern. San Francisco: Holden-Day, 1966, and New York: Dell, 1966. A translation, extension, and revision of Shklovskii’s Vselennaia, Zhizn, Razum (Universe, life, mind.)

Supernovae. Translated from the original manuscript by Literaturprojekt, Innsbruck, Austria. Interscience Monographs and Texts in Physics and Astronomy, vol. 21. New York: Wiley, 1968. 2nd ed. Princeton, NJ: Princeton University Press, 1979.

Stars: Their Birth, Life, and Death. Translated by Richard B. Rodman, foreword by Carl Sagan, prologue by J. P. Ostriker. San Francisco: W. H. Freeman, 1978.

“The Relationship between Supernovae and Their Remnants.” Publications of the Astronomical Society of the Pacific92 (1980): 125–126.

“Cosmological Estimate of the Age of Stars Exploding as Type I Supernovae.” Nature304 (1983): 513.

With I. G. Mitrofanov. “On the Astronomical Nature of the Sources of Gamma-Ray Bursts.” Monthly Notices of the Royal Astronomical Society212 (1985): 545–551.

Five Billion Vodka Bottles to the Moon: Tales of a Soviet Scientist. Translated and adapted by Mary Fleming Zirin and Harold Zirin. New York: W. W. Norton, 1991. Autobiographical tales from Shklovskii’s life, written between 1981 and 1984, circulated in typescript within the Soviet scientific community. Twenty-four of the thirty-five samizdat chapters, rearranged in somewhat chronological order and with some digressions eliminated, but charming nonetheless, are presented in English translation in this book. Also, the introduction includes extensive personal reminiscences by the American radio astronomer Herbert Friedman. Parts of some of Shklovskii’s tales are quoted, in English translation, in N. S. Kardashev and L. S. Marochnik, “The Shklovsky Phenomenon.” In Astrophysics on the Threshold of the 21st Century, edited by N. S. Kardashev. Philadelphia: Gordon & Breach, 1992.


Davidson, Keay. Carl Sagan: A Life. New York: John Wiley & Sons, 1999. Thoroughly details Shklovskii’s collaboration with Sagan.

Dick, Steven J. The Biological Universe: The Twentieth-Century Extraterrestrial Life Debate and the Limits of Science. Cambridge, U.K.: Cambridge University Press, 1966. Discusses the search for extraterrestrial intelligence by Shklovskii and others in the Soviet Union and compatibility with communist ideology.

Eremeeva, A. I. “Political Repression and Personality: The History of Political Repression against Soviet Astronomers.” Journal for the History of Astronomy 26 (1995): 297–324. Describes the purge of Soviet astronomers.

Friedman, Herbert. “Joseph Shklovsky and X-ray Astronomy.” In Astrophysics on the Threshold of the 21st Century, edited by N. S. Kardashev. Philadelphia: Gordon & Breach, 1992.

Ginzburg, V. L. “Remarks on My Work in Radio Astronomy.” In The Early Years of Radio Astronomy: Reflections Fifty Years after Jansky’s Discovery, edited by W. T. Sullivan. Cambridge, U.K.: Cambridge University Press, 1984. On a career running parallel to Shklovskii's, including graduate study at the Shternberg State Astronomical Institute and participation in the Brazil eclipse expedition. See also next item.

———. “Notes of an Amateur Astrophysicist.” Annual Review of Astronomy and Astrophysics28 (1990): 1–36.

Goldberg, Leo. “Josif Shklovsky: A Personal Reflection.” Sky & Telescope 70, no. 2 (August 1985): 109.

Greenstein, Jesse, and Rudolph Minkowski. “The Crab Nebula as a Radio Source.” Astrophysical Journal 118 (1953): 1–15.

McCutcheon, Robert A. “Stalin’s Purge of Soviet Astronomers.” Sky & Telescope78, no. 4 (October 1989): 352–357.

Minkowski, Rudolph. “The Crab Nebula.” Astrophysical Journal 96 (1942): 199–213. Reprinted with commentary in A Source Book in Astronomy & Astrophysics, edited by Kenneth R. Lang and Owen Gingerich. Cambridge, MA: Harvard University Press, 1979.

Moroz, Vasilii I. “A Short Story about the Doctor.” Astrophysics & Space Science B252 (1997): 1–2, 5–14.

Oort, Jan H. “The Crab Nebula.” Scientific American196, no. 3

(March 1957): 52–60. On Shklovskii’s hypothesis of synchrotron radiation as the source of its emission. Salomonovich, A. E. “The First Steps of Soviet Radio Astronomy.” In The Early Years of Radio Astronomy: Reflections Fifty Years after Jansky’s Discovery, edited by W. T. Sullivan. Cambridge, U.K.: Cambridge University Press, 1984. Comments on Shklovskii and the Brazil expedition.

Shcheglov, P. V. “Iosif Samuilovich Shklovskii.” Quarterly Journal of the Royal Astronomical Society27, no. 4 (1986): 700–702. Translated from the Soviet astronomical journal Astronomicheskii Vestnik 19, no. 4 (1985): 359–361. This and other Soviet obituaries of Shklovskii, from Soviet Astronomical Letters11, 2 (March–April 1985): 131–132, and Astronomicheskii Zhurnal 62 (May–June 1985): 618–619, are available in English translation in the NASA Astrophysics Data System ( The Soviet obituaries are less informative and revealing of human character.

Strelnitski, Vladimir S. “The Early Post-War History of Soviet Radio Astronomy.” Journal for the History of Astronomy 26 (1985): 349–362. Comments on Shklovskii and the Brazil expedition.

Sullivan, Walter. “Iosif S. Shklovosky [sic], Astronomer, Dies.” New York Times, 6 March 1985. Herbert Friedman was the source for this brief obituary notice.

van de Hulst, H. C. “Two Great Astrophysicists: Some Personal Reflections.” In Astrophysics on the Threshold of the 21st Century, edited by N. S. Kardashev. Philadelphia: Gordon & Breach, 1992.

Weaver, Harold. “The Award of the Bruce Gold Medal for 1972 to Professor J. S. Shklovsky.” Mercury 1 (July–August 1972): 6–7.

Norriss Hetherington

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