Viktor Ambartsumian

Viktor Hambardzumyan
File:Viktor Hambardzumyan.jpg
Born	(1908-09-18)September 18, 1908 Tbilisi, Russian Empire
Died	August 12, 1996(1996-08-12) (aged 87) Byurakan, Armenia
Nationality	Soviet Armenia
Scientific career
Fields	theoretical astrophysics

Viktor Hambardzumyan (Armenian: Վիկտոր Համբարձումյան, Russian: Ви́ктор Амаза́спович Амбарцумя́н) (September 18 [O.S. September 5] 1908 – August 12, 1996) was a Soviet Armenian scientist, and one of the founders of theoretical astrophysics.^[1] He worked in the field of physics of stars and nebulae, stellar astronomy, dynamics of stellar systems and cosmogony of stars and galaxies, contributed to Mathematical physics. Hambardzumyan was the President of the International Astronomical Union from 1961 till 1964, was twice elected the President of the International Council of Scientific Unions (1966–1972), was a member of the USSR Academy of Sciences, and foreign member of the Royal Society,^[2] the US National Academy and the Indian Academy of Sciences. Among his numerous awards are Stalin Prize (1946,1950), Hero of Socialist Labor (1968,1978), State Prize of the Russian Federation, Gold Medal of the Royal Astronomical Society,^[3] Bruce Gold Medal^[4] from the Astronomical Society of the Pacific, National Hero of Armenia. Hambardzumyan was the founder of Byurakan Observatory.^[5][6]

Hambardzumyan was born to an Armenian family in Tbilisi in 1908. His father was the philologist and writer Hamazasp Asaturovich Hambardzumyan, the translator of Homer’s Iliad into Armenian. In 1924 Victor entered the physico-mathematical department of Leningrad State Pedagogical Institute and then of Leningrad State University. As a student, in 1926, he published his first scientific article, devoted to sun jets. Hambardzumyan continued his postgraduate studies at Pulkovo Observatory, under the guidance of professor Aristarkh Belopolsky in 1928–1931.

His work first came to prominence in physics when in 1929 with Dmitry Ivanenko he published a paper demonstrating that atomic nuclei could not be made from protons and electrons. Three years later this was confirmed when Sir James Chadwick discovered neutrons, which with protons make up atomic nuclei.

In 1930 he married Vera Feodorovna Klochihina (born at Lisva, Solikamsk uyezd, Perm). After three years of affiliation at Leningrad University in 1934 Hambardzumyan founded and headed the first astrophysics chair. In 1939–1941 Hambardzumyan was the director of the Leningrad University Observatory. In 1940 he joined the Communist Party

The War found him holding the position of the pro-rector of Leningrad State University. The scientific laboratories of the University were evacuated in 1941 to remote Elabuga (Tatarstan) where Hambardzumyan spent four years directing the work of the refugee laboratories. In 1939 Ambartsumian was elected a correspondent member of the Academy of Sciences of the USSR. In 1953 he became a full academician of the Academy. In 1943, the heaviest period of the war, the Armenian Academy of Sciences was founded. Iosif Orbeli was appointed as the president and Hambardzumyan as the vice president of Armenian SSR Academy.

In 1947 Hambardzumyan was elected as the president of the Armenian SSR Academy and since then he was invariably re-elected to the position till 1993. In 1993 he became the Honorary President of the Armenian National Academy.

In 1946 the Byurakan Astrophysical Observatory was founded. Hambardzumyan became its first Director and directed the Observatory till 1988. Hambardzumyan was the President of the International Astronomical Union from 1961 till 1964. He was twice elected the President of the International Council of Scientific Unions (1966–1972).

Congratulating Hambardzumyan on his 80th birthday, Subrahmanyan Chandrasekhar who won the Nobel Prize for Physics in 1983, wrote,

"The only other astronomer of this century who compares with Academician Hambardzumyan in his consistency and devotion to astronomy is Professor Jan Oort; but they would appear to be dissimilar in every other way. It will be a worthy theme for a historian of science of the twenty-first century to compare and contrast these two great men of science. He is an astronomer. There can be no more than two or three astronomers in this century who can look back on a life so worthily devoted to the progress of astronomy. (Astrophysics, Vol 29, No.1, p 408, 1989)."

^[7]

Hambardzumyan died in August 1996 in Byurakan and is buried next to the Grand Telescope Tower.

In 1932 “Monthly Notices” of the Royal Astronomical Society published a paper by V.A.Hambardzumyan “On the radiative equilibrium of a planetary nebula” nowadays considered to be the cornerstone of the modern theory of the gas nebulae. In a series of research articles by Hambardzumyan that topic was developed further. In one of these articles Ambartsumian (with N.A.Kozyrev) managed to evaluate for the first time the masses of the gas shells ejected by the novas. Elaborate methods developed by Hambardzumyan were applied in the research of gas shells of the non-stationary stars. The evaluations of the masses proved significant in the problems of the stellar evolution. In particular they resulted in the identification of the symptoms of the pending changes in the life of a star. Ambartsumian laid the foundation of the theory of the star shells and gas nebulae and explained many particularities of their spectra.

In 1936 Hambardzumyan gave an elegant solution of a mathematical problem posed by British scientist Arthur Eddington, viz. determination of the distribution of the stars spatial speeds basing on the distribution of their radial speeds. The solution was published in the “Monthly Notices” by recommendation of Arthur Eddington himself. Decades later the same mathematical problem reappered in the context of medical computer diagnostics. Eventually (1979) that mathematical topic was marked by the Nobel Prize in medicine “For the development of computer assisted tomography”. The research conducted by Hambardzumyan in the stellar systems statistics and dynamics laid the foundations of the statistical mechanics of the stellar systems. For this particular contribution Ambartsumian was rewarded with the State Prize of Russian Federation in 1995.

In 1935-1937 Hambardzumyan engaged in a debate with British scientist James Jeans over the age of the Milky Way (our own galactic stellar system), proving that the Milky Way is at least 1000 times younger than the estimate given by Jeans and previously accepted by the scientific community.

A series of Hambardzumyans articles is dedicated to the research of inter-stellar matter in the Galaxy. Hambardzumyan puts forward an entirely new concept, that the light absorption in the Galaxy is caused by the presence of numerous dust nebulae or “absorbing clouds” in the inter-stellar space. Based on this concept of patchy structure of the inter-stellar absorbing matter the fluctuation theory was developed, which became a new direction in the astronomy.

Hambardzumyan's marvelously elegant formulation of the fluctuations in brightness in the Milky Way: in the limit of infinite optical depth~ the probability distribution of the fluctuations in the brightness of the Milky Way is invariant to the location of the observer. In the related series of investigations, in part in association with Academician Markarian, Ambartsumian introduced for the first time the now commonly accepted notion that interstellar matter occurs in the form of clouds.

During the years of the World War II Hambardzumyan created a new theory of light diffusion in turbid media, based on invariance principle invention of his own. Using that mathematical tool Hambardzumyan resolved a number of nonlinear problems of the light diffusion. The invariance principle formulated by Hambardzumyan and various modifications of this principle presently are being widely used to solve extremely complicated problems in astrophysics, mathematical and theoretical physics, electronics, geophysics, atmospheric physics, and other areas of science. These problems and the associated mathematical apparatus are constantly becoming more complicated, but the basis is still Hambardzumyan's invariance principle. In their book ‘Invariant Imbedding. Radiative Transfer in Slabs of Finite Thickness’ R.E.Bellman, R.E.Kalaba and M.C.Prestrud write that “As a result of this pioneering work, new analitic treatments were made available and simplified computational solutions were obtained. These ideas were further developed and extensively generalized by Chandrasekhar in a series of fundamental papers and in 1950 in his book... Many otherwise intractable problems were tamed, and great adwances were made”. (American Elsevier Publishing Co., 1963, p1.) Hambardzumyan, himself, held the invariance principle in special regard and always considered it to be one of his most successful and beloved creations. In 1946 for the creation of the theory of lights diffusion in turbid media Hambardzumyan was awarded his first Stalins Prize.

Hambardzumyans theoretical analysis based on of the observational material for stellar systems belonging to our Galaxy resulted in a discovery of a new type of stellar systems. These expanding systems endowed with a positive energy he named “stellar associations” and proved their relatively young age. This proved to be a revolutionary basis in stellar cosmology, since it implied that the star formation process in the Galaxy is going on even today and the stars are born in groups. In 1950 Amartsumian was awarded his second Stalin Prize for the discovery and the research of the new type of stellar systems.

The concept of stellar association was not immediately accepted by the astronomical community though. Many years later Chandrasekhar wrote: "I recall the early scepticism with which this discovery was received by the astronomers of the 'establishment' when I first gave an account of (Hambardzumyan's) paper at the colloquium at the Yerkes Observatory in late 1950."

Observations of expansion (as predicted by Ambartsumian) were reported for some associations, e.g. by A. Blaauw for Perseus II, Scorpio-Centaurus, etc.

No less interesting are the results of Hambardzumyan’s research in the so-called continuous emission, observed in the spectras of the young stars of the TAU Taurus type and their satellite non-stationary stars. This research led to important conclusions as regards the nature of the stellar energy sources. Hambardzumyan proposed principally new concept of p-star matter. As opposite to the classical hypotheses suggesting that the stars have been formed as a result of condensation of diffuse matter, the new hypothesis postulated the existence of massive bodies, the “proto-stars”. The process of disintegration of proto-stars is responsible for the formation of the stars in the associations.

In interpreting the cosmogonic role of stellar associations Hambardzumyan went on to argue the necessity of change to existing views on star formation; namely, for dissolution and against condensation. Clearly, his early work on the expansion of the planetary nebulae and the fact that those objects result from the ejection of the outer layers of stars-the dynamical dissolution of star clusters via evaporation and of associations-created a logical background for his radical conclusion that the basic evolutionary processes in the Universe are not contraction and condensation. On the contrary, they are always outgoing from some denser state of matter. Thus, he postulated the existence of 'protostars', i.e. superdense objects as protogenitors of stars, nebulae, diffuse matter, etc.

Hambardzumyan dedicated much research to the evolution of the galaxies – huge stellar systems resembling our Galaxy. He authored the new concept of activity of the galactic nuclei (cores, central condensations), to have a decisive role in the genesis and evolution of the galaxies and their systems. Owing to that vision, the study of the grand scale non-stationary phenomena, observed in the galaxies became the central subject of the extra-galaxy astronomy. An important research of Hambardzumyan and his followers was dedicated to the blue ejections from the nuclei of the gigantic galaxies, galaxy systems of new type, the so-called compact galaxies, etc. Hambardzumyan’s first Solvay lecture, delivered in 1958, concerning the explosion of nuclei of the galaxies, was groundbreaking. That first lecture and the development it starts were described by Jerzy Neyman in his article ‘Reminiscences of a Revolutionary Period in Cosmology’. As Neumann recalled, despite initial scepticism, “Hambardzumyan’s arguments and many-syded documentation made the attending scolars think, and there followed several important international developments...”Neyman concluded that “Evidence in favor of the Hambardzumyan’s Hypothesis is now overwhelming. My hearty congratulations to Professor V.A.Hambardzumyan, the Copernican Revolutionary...!” (Problems of Physics and Evolution of the Universe, Publishing House of the Armenian Academy of Sciences, Yerevan, 1978, pp. 243–250.)

A citation from the article of Nobel prize winner A.M.Kormak “Computed Tomography: some history and recent developments” (Proc. Of Symposia in Applied Mathematics, Vol 29, p35, 1985):

“... Radon’ s problem in a three dimensional velocity space...

... Hambardzumyan gave the solution in two and three dimensions in the same form as Radon. Furthermore, he took groups of stars of three different spectral types, with four to five hundred stars in each group, and he used his theoretical results to deduce their actual velocity distributions from the distributions of their radial velocities....

... This is the first numerical inversion of the Radon transform and it gives the lie to the often made statement that computed tomography would be impossible without computers. Details for the calculation are given in Hambardzumyan’s paper, and they suggest that even in 1936 computed tomography might have been able to make significant contributions to, say, the diagnosis of tumors in the head....

... it seems to me quite possible that Hambardzumyan’s numerical methods might have made significant contributions to that part of medicine had they been applied in 1936....”

At the beginning of Hambardzumyan's career, at the end of the 1920s and beginning of the 1930s, the range of scientific interests of Viktor Hambardzumyan was very far reaching. He studied several extremely timely problems in physics and mathematics. Among the very first of these studies was his talk, given in 1929 at the Kharkov Physico-Technical Institute, where prestigious international conferences on quantum physics were organized at that time. Then Hambardzumyan proposed for the first time an entirely new idea regarding the quantization of space. Although is true that the idea was not accepted then, its incorrectness was not proven; Ambartsumian did not continue his studies in this area, somehow obeying the opinion of authoritative scientists who thought that nothing good would result if our continuous space were made discrete.

In his article entitled "On the new quantum crisis," about the quantization of space, a pioneer of quantum gravity Matvei Bronshtein, who was shot in 1937, wrote: "Since we are obviously speaking here about a four-dimensional grid that includes both space and time, a privileged coordinate system clearly designates an absolute time and three predominant directions in a motionless space. But this contradicts both the theory of relativity and experiment: in reality space-time is isotropic, all coordinate systems are equivalent in it, and all the equations are, as they say, invariant with respect to Lorentz transformations (that is, they have the same form in all coordinate systems). This is the difficulty with relativistic invariance (invariance with respect to Lorentz transformations) and Heisenberg could not overcome it; a remarkable way of overcoming it has been found by Hambardzumyan and the young Cambridge mathematician Ursell." Almost 80 years have passed since that time, but the problem of space quantization has still not been completely solved, although from time to time some researchers return to the topic, which confirms the ongoing timeliness of the problem.^[8]

Hambardzumyan, together with Ivanenko, first proposed the idea that in the course of interactions of elementary particles with nonzero rest masses, some of them might be created or annihilated. The idea of the creation of particles with nonzero rest masses was absolutely new and did not follow from classical notions. The Ambarzumian - Ivanenko hypothesis of creation of massive particles ( 1930) became a cornerstone of contemporary quantum field theory.

Another Hambardzumyan's paper, written jointly with Dmitrii Ivanenko in the very beginning of Hambardzumyan's scientific career (Dokl. AN SSSR, ser. A, No. 6, p. 153 (1930)), can be included in the list of the most outstanding papers on the structure of the atomic nucleus. Contrary to the prevailing opinion of the time that the nucleus consists of protons and electrons, they proved that free electrons cannot exist within the nucleus and that some neutral particles must be present besides the protons. In fact, this was a prediction of the existence of the neutron, made two years before James Chadwick discovered this particle.

While still a student Hambardzumyan was very much interested in quantum physics, and thoroughly studied the theory of atomic structure, the formation of energy levels, and Schroedinger's equation and its properties, and when he mastered the theory of eigenvalues of differential equations, he pointed out the apparent analogy between discrete energy levels and the eigenvalues of differential equations. He then asked: given a family of eigenvalues, is it possible to find the form of the equations whose eigenvalues they are? Essentially Hambardzumyan was examining the inverse Sturm-Liouville problem, which dealt with determining the equations of a vibrating string. This paper was published in 1929 in the German physics journal Zeitschrift für Physik and remained in oblivion for a rather long time. Describing this situation after many decades, Hambardzumyan said, "If an astronomer publishes an article with a mathematical content in a physics journal, then the most likely thing that will happen to it is oblivion." Nevertheless, toward the end of the Second World War this article was found by Swedish mathematicians and formed the starting point for a large series of studies. Thus, an article by the 20-year-old Hambardzumyan opened up a whole area of research on inverse problems and became the foundation of an entire discipline.

Interesting to note, when Hambardzumyan summarized the types of research results from his long scientific career, he always placed "inverse problems" in a special group of his most beloved creations.

It was in the early 1950s when Prof. Victor Hambardzumyan first raised the issue of the Activity of Nuclei of Galaxies (AGN). In his famous report at the Solvay Conference on Physics (Brussels, 1958) Ambartsumian said that enormous explosions take place in galactic nuclei and as a result a huge amount of mass is expelled. In addition if this is so, these galactic nuclei must contain bodies of a huge mass and unknown nature. During a break in the session Walter Baade went up to Hambardzumyan and said, "Professor Ambartsumian, you have come from the Soviet Union, and I from America. Logically speaking, you should be a materialist, and I an idealist. But what you have just said is nothing other than a pure idealism! It’s fantastic! You speak about some kind of “non-stellar“ objects which no one has seen. So it must be something inexplicable, mysterious."

The idea about the activity of galactic nuclei at first was accepted skeptically and only after many years, under the pressure of observations (the discovery of quasars, radio outbursts of galaxies, consequences of explosions in nuclei, ejection from nuclei, etc.) did it gain recognition. The concept of AGN now is widely accepted.^[9]

Ten years after the Solvay conference, at the plenary session of the IAU in Prague, the well-known American astronomer Alan Sandage said, “today, no astronomer would deny the mystery surrounding the nuclei of galaxies or that the first to recognize the rich reward held in this treasury was Viktor Ambartsumian.”

As Victor Hambardzumyan, himself, noted, the concept of active galactic nuclei occupies a special place among his scientific ideas. It was proposed by Ambartsumian more than half a century ago and was recognized by the U.S. National Academy of Sciences as revolutionary, on a copernican scale.

Hambardzumyan combined his work in science with lecturing and other pedagogic activity. He is the author of the first in the USSR manual “Theoretical astrophysics” (1939) and a co-author of the course “Theoretical astrophysics” (1952), translated into many languages. From 1931 he lectured at Lenigrad University. In 1937 Hambardzumyan founded in LU the first in the USSR Faculty of Astrophysics, which he headed till 1947. In 1939-1941 Ambartsumian held the positions of the Director of the LU Observatory and the pro-rector of LU for science. In 1941-1943 he was the Director of the Elabuga branch of the LU. In 1944 Ambartsumian founded a faculty of Astrophysics in Yerevan University. Hambardzumyan founded scientific schools in Leningrad and Byurakan that had influenced many branches of astronomy. V.A. Hambardzumyan immensely contributed into science popularization by publishing booklets and articles on different problems of astrophysics.

Hambardzumyan was a remarkable science organizer in Armenia, Russia and on the international level. He was the founder and the director of Byurakan Observatory - one of the main astronomy centers of the USSR, the vice-president and then the president of Armenian Academy of Sciences, member of presidium of Academy of Sciences of the USSR, the vice-president (1948–1955) and the president (1961-1964 of the International Astronomical Union and twice was elected as the president of the International Council of Scientific Unions (1966–1972).

In 1940 Ambartsumian became a member of the Communist Party of the USSR. In 1947 was elected to the Supreme Soviet of the Armenian SSR. From 1948 till 1989 Ambartsumian as a member of the Central Committee of the Communist Party of Armenia. In fact Hambardzumyan personifies the state policy of promotion of Science in the Soviet Republic of Armenia that included considerable capital investments and repatriation of scientists. He was a permanent delegate from Armenia to the USSR Supreme Soviet between 1950–1990, was a delegate of 19th, 22d and 25th Congresses of the Communist Party of the USSR; in 1989 was elected to the USSR Congress of the People's Deputies.

Hambardzumyan was awarded two Stalin Prizes (1946, 1950), the Russian Federation State Award and M.V.Lomonosov (1971) Gold Medal of Academy of Science of the USSR. Hambardzumyan was twice nominated the title of a Hero of Social Labor, and received many medals and orders. Hambardzumyan was elected as an honoree or international member of the Academies of Science of Austria, Belgium, Bulgaria, Democratic Republic of Germany, Georgia, Denmark, Italy, Netherland, the USA, France, Sweden, New York Academy of Science, German Academy of Science (“Leopoldina”) in Halle (DRG), Royal Astronomical Societies of England and Canada, American Astronomical Society, Philosophical Society of Cambridge, as an honoree doctor the Universities of Liege, Australian National, La-Plata Observatory, Paris and Copernicus in Torin. He was elected a Foreign Honorary Member of the American Academy of Arts and Sciences in 1958.^[10]

Hambardzumyan was awarded Gold Medals of the Astronomical Society of the Pacific (1959) and British Royal Astronomical Societies (1960), Gold Medal of Slovak Academy of Science (1970), Prix Jules Janssen of the French Astronomical Society (1956), Helmgolz Medal of German Academy of Science in Berlin (1971), Cotenius Medal of the German Academy of Sciece (“Leopoldina”) in Halle (DRG) (1974), Medal of the Czechoslovak Academy of Science (1984). A minor planet discovered by T. M. Smirnova on May 14, 1972 in Crimea Observatory was named after Ambartsumian (1905 Ambartsumian).

Named after him

• Minor planet 1905 Ambartsumian
• Byurakan Astrophysical Observatory

The President of Armenian Republic had instituted a scientific reward: the Ambartsumian prize. It will be granted for outstanding contributions in the field of astrophysics and in adjacent scientific fields, i.e., mathematics and physics. The prize which is worth of $500,000 will be awarded independently of winner's nationality. The prize was awarded for the first time in 2010.

1.1. With a purpose of perpetuation of the National Hero of Armenia, celebrated scientist academician V.A. Hambardzumyan’s memory, as well as for the promotion of development of his scientific heritage, the National Hero of Armenia, academician V.A. Hambardzumyan International Science Prize has been established by the President of RA as equivalent Drams to 500000 US dollars.

1.2. The academician V.A. Hambardzumyan Prize is being awarded by the President of Republic of Armenia.

1.3. Suggestions on the academician V.A. Hambardzumyan Prize are being presented by the special Committee attached to the Presidium of NAS RA, the staff of which is being established by the Government of RA by the presentation of the Presidium of NAS RA.

1.4. The academician V.A. Hambardzumyan Prize includes cash award, diploma of V.A. Hambardzumyan Prize winner, honorable mark (medal) and its corresponding certificate.

1.5. The academician V.A. Hambardzumyan Prize is being awarded to scientists of any country of the world for unique scientific works in the fields of astrophysics, as well as the fields of physics and mathematics adjacent to the scientific activity connected with V.A. Hambardzumyan.

1.6. To applying for the Prize, a work may be presented by an author or authors’ group (not more than 3 persons). The cash award is being equally shared between the applicants, and the diploma, the medal and the certificate are being awarded to each applicant. The Prize may not be awarded to an applicant for the second time.

1.7. The Prize is awarded every 2 years and 2010 is considered as the first award year.

1.8. In the absence of deserved candidates among the applicants for V.A. Hambardzumyan Prize, the mentioned Prize is not being awarded in the given year.

The details are on the site of National Academy of Armenia: [1]

• V. A. Ambartsumian, Theoretical Astrophysics. Translated from the Russian ("Teoreticheskaya astrofizika", Moscow, 1952) by J.B. Sykes, New York: Pergamon Press, 1958
• V.A. Ambartsumian, A Life in Astrophysics : Selected Papers of Viktor Ambartsumian, edited by Rouben V. Ambartsumian, New York: Allerton Press, 1998

• В. А. Амбарцумян. Научные труды в трех томах. Изд.АН Арм ССР. 1960-1988

• В. А. Амбарцумян. Эпизоды жизни. Изд.АН Арм ССР. 2000

• Die Sternassoziationen und die Entstehung der Sterne. Akademie-Verlag, Berlin, 1951.

• Philosophische Probleme der modernen Kosmologie. Deutscher Verlag der Wissenschaften, Berlin, 1965.

• Probleme der modernen Kosmogonie. Akademie-Verlag, Berlin, 1980.

• Struktur und Formen der Materie, dialektischer Materialismus und moderne Naturwissenschaft. Deutscher Verlag der Wissenschaften, Berlin, 1969.

• Theoretische Astrophysik. Deutscher Verlag der Wissenschaften, Berlin, 1957.

• Ambartsumian featured on the 100 Armenian Dram banknote in 1998.
• Bruce Medal page
• Articles and memoirs.

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