Sergei Kopeikin (born April 10, 1956) is a

USSR The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen nationa ...

-born theoretical

physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate cau ...

and

astronomer An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, moons, comets and galaxies – in either ...

presently living and working in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

, where he holds the position of Professor of Physics at the

University of Missouri The University of Missouri (Mizzou, MU, or Missouri) is a public land-grant research university in Columbia, Missouri. It is Missouri's largest university and the flagship of the four-campus University of Missouri System. MU was founded in ...

in Columbia, Missouri. He specializes in the theoretical and experimental study of

gravity In physics, gravity () is a fundamental interaction which causes mutual attraction between all things with mass or energy. Gravity is, by far, the weakest of the four fundamental interactions, approximately 1038 times weaker than the stro ...

and

general relativity General relativity, also known as the general theory of relativity and Einstein's theory of gravity, is the geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of gravitation in modern physics ...

. He is also an expert in the field of the astronomical reference frames and time metrology. His general relativistic theory of the Post-Newtonian reference frames which he had worked out along with Victor A. Brumberg, was adopted in 2000 by th
resolutions
of the

International Astronomical Union The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreac ...

as a standard for reduction of ground-based astronomical observation. A computer program Tempo2 used to analyze radio observations of pulsars, includes several effects predicted by S. Kopeikin that are important for measuring parameters of the binary pulsars, for testing general relativity, and for detection of gravitational waves of ultra-low frequency. Sergei Kopeikin has worked out a complete post-Newtonian theory of equations of motion of N extended bodies in scalar-tensor theory of gravity with all mass and spin

multipole moments A multipole expansion is a mathematical series representing a function that depends on angles—usually the two angles used in the spherical coordinate system (the polar and azimuthal angles) for three-dimensional Euclidean space, \R^3. Similarly ...

of arbitrary order and derived the

Lagrangian Lagrangian may refer to: Mathematics * Lagrangian function, used to solve constrained minimization problems in optimization theory; see Lagrange multiplier ** Lagrangian relaxation, the method of approximating a difficult constrained problem with ...

of the relativistic

N-body problem In physics, the -body problem is the problem of predicting the individual motions of a group of celestial objects interacting with each other gravitationally.Leimanis and Minorsky: Our interest is with Leimanis, who first discusses some histor ...

. In September 2002, S. Kopeikin led a team which conducted a high-precision

VLBI Very-long-baseline interferometry (VLBI) is a type of astronomical interferometry used in radio astronomy. In VLBI a signal from an astronomical radio source, such as a quasar, is collected at multiple radio telescopes on Earth or in space. T ...

experiment to measure the fundamental

speed of gravity In classical theories of gravitation, the changes in a gravitational field propagate. A change in the distribution of energy and momentum of matter results in subsequent alteration, at a distance, of the gravitational field which it produces. In ...

, thus, confirming the Einstein's prediction on the relativistic nature of gravitational field and its finite speed of propagation. He is also involved in studies concerning the capabilities of the Lunar Laser Ranging (LLR) technique to measure dynamical features of the

General Theory of Relativity General relativity, also known as the general theory of relativity and Einstein's theory of gravity, is the differential geometry, geometric scientific theory, theory of gravitation published by Albert Einstein in 1915 and is the current descr ...

in the lunar motion. He has critically analyzed the claims of other scientists concerning the possibility of LLR to measure the gravitomagnetic interaction. Prof. Kopeikin organized and chaired three international workshops on the advanced theory and model of the Lunar Laser Ranging experiment. The LLR workshops were held in the International Space Science Institute ( Bern, Switzerland) in 2010-2012. Recently, S. Kopeikin has been actively involved in theoretical studies on relativistic geodesy and applications of

atomic clock An atomic clock is a clock that measures time by monitoring the resonant frequency of atoms. It is based on atoms having different energy levels. Electron states in an atom are associated with different energy levels, and in transitions betwe ...

s for high-precision navigation and in

geodetic datum A geodetic datum or geodetic system (also: geodetic reference datum, geodetic reference system, or geodetic reference frame) is a global datum reference or reference frame for precisely representing the position of locations on Earth or other pla ...

. He has provided an exact relativistic definition of

geoid The geoid () is the shape that the ocean surface would take under the influence of the gravity of Earth, including gravitational attraction and Earth's rotation, if other influences such as winds and tides were absent. This surface is extended ...

, and worked out the post-Newtonian concepts of the Maclaurin spheroid and normal gravity formula. S. Kopeikin's workshop on spacetime metrology, clocks and relativistic geodesy is held in the International Space Science Institute ( Bern, Switzerland). Kopeikin was born in Kashin, a small town near

Moscow Moscow ( , US chiefly ; rus, links=no, Москва, r=Moskva, p=mɐskˈva, a=Москва.ogg) is the capital and largest city of Russia. The city stands on the Moskva River in Central Russia, with a population estimated at 13.0 millio ...

in what was then the

. He graduated with excellence from Department of Astrophysics of

Moscow State University M. V. Lomonosov Moscow State University (MSU; russian: Московский государственный университет имени М. В. Ломоносова) is a public research university in Moscow, Russia and the most prestigious ...

in 1983 where he studied

unde
Leonid Grishchuk
In 1986, he obtained a

Ph.D. A Doctor of Philosophy (PhD, Ph.D., or DPhil; Latin: or ') is the most common degree at the highest academic level awarded following a course of study. PhDs are awarded for programs across the whole breadth of academic fields. Because it is ...

in relativistic astrophysics from the

Space Research Institute The Russian Space Research Institute (russian: Институт космических исследований Российской академии наук, Space Research Institute of the Russian Academy of Sciences, SRI RAS, Russian abbrevia ...

. His Ph.D. thesis was advised by

Yakov Borisovich Zel'dovich Yakov Borisovich Zeldovich ( be, Я́каў Бары́савіч Зяльдо́віч, russian: Я́ков Бори́сович Зельдо́вич; 8 March 1914 – 2 December 1987), also known as YaB, was a leading Soviet physicist of Bel ...

and presented a first general-relativistic derivation of the conservative and radiation reaction forces in the

Post-Newtonian expansion In general relativity, the post-Newtonian expansions (PN expansions) are used for finding an approximate solution of the Einstein field equations for the metric tensor. The approximations are expanded in small parameters which express orders of ...

of the gravitational field of a binary system of two extended, massive bodies. In 1991, he obtained a

Doctor of Science Doctor of Science ( la, links=no, Scientiae Doctor), usually abbreviated Sc.D., D.Sc., S.D., or D.S., is an academic research degree awarded in a number of countries throughout the world. In some countries, "Doctor of Science" is the degree used f ...

degree in Physics and Mathematics from

and moved to

Tokyo Tokyo (; ja, 東京, , ), officially the Tokyo Metropolis ( ja, 東京都, label=none, ), is the capital and List of cities in Japan, largest city of Japan. Formerly known as Edo, its metropolitan area () is the most populous in the world, ...

( Japan) in 1993 to teach astronomy in

Hitotsubashi University is a national university located in Tokyo, Japan. It has campuses in Kunitachi, Kodaira, and Chiyoda. One of the top 9 Designated National University in Japan, Hitotsubashi is a relatively small institution specialized solely in social science ...

. He was adjunct staff member in National Astronomical Observatory of Japan in 1993-1996 and a visiting professor in the same observatory in 1996-1997. Kopeikin moved to

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...

in 1997 and worked in the Institute for Theoretical Physics of

Friedrich Schiller University of Jena The University of Jena, officially the Friedrich Schiller University Jena (german: Friedrich-Schiller-Universität Jena, abbreviated FSU, shortened form ''Uni Jena''), is a public research university located in Jena, Thuringia, Germany. The un ...

and in

Max Planck Institute for Radio Astronomy The Max Planck Institute for Radio Astronomy (MPIfRA) (German: ''Max-Planck-Institut für Radioastronomie'') is located in Bonn, Germany. It is one of 80 institutes in the Max Planck Society (German: Max-Planck-Gesellschaft). History By com ...

until 1999. He had joined Department of Physics and Astronomy of the

in February 2000 where he got tenure in 2004. He has been married to Zoia Kopeikina (daughter of Solomon Borisovich Pikelner) since 1980, they have four daughters, four granddaughters and three grandsons. As of December 2019 the family lives in Columbia,

Missouri Missouri is a state in the Midwestern region of the United States. Ranking 21st in land area, it is bordered by eight states (tied for the most with Tennessee): Iowa to the north, Illinois, Kentucky and Tennessee to the east, Arkansas t ...

and

Texas Texas (, ; Spanish: ''Texas'', ''Tejas'') is a state in the South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2020, it is the second-largest U.S. state by ...

Bibliometric information

Prof. Kopeikin has published 198 scientific papers and 2 books. He was an editor of two other books on advances in relativistic celestial mechanics. According t
Google Scholar Citations
program, the

h-index The ''h''-index is an author-level metric that measures both the productivity and citation impact of the publications, initially used for an individual scientist or scholar. The ''h''-index correlates with obvious success indicators such as ...

of S.M. Kopeikin is 39, his

i10-index Author-level metrics are citation metrics that measure the bibliometric impact of individual authors, researchers, academics, and scholars. Many metrics have been developed that take into account varying numbers of factors (from only considering ...

is 89, while the total number of citations is 5171. As of March 2022,

NASA ADS The SAO/NASA Astrophysics Data System (ADS) is an online database of over 16 million astronomy and physics papers from both peer reviewed and non-peer reviewed sources. Abstracts are available free online for almost all articles, and full scanned a ...

returns for him an

of 31, while his tori and riq indices are 49.6 and 180, respectively.

References

External links

The real reason why the Pioneer spacecrafts appear to be slowing down
- theoretical study of the Pioneer anomaly effect
Test for Einstein's gravity speed theory
- a BBC News article about the preparations to the "speed-of-gravity" experiment
Speed of Gravity Measured for First Time
- a NRAO press-release on VLBI experiment measured the ultimate speed of gravity

- The New York Times, January 8, 2003
Physicist Disputes Speed of Gravity Claim
- American Physical Society News article, dated June 2003, describing criticism of the results
Aberration and the Fundamental Speed of Gravity in the Jovian Deflection Experiment
- a rebuttal of the criticism
Gravimagnetism, Causality, and Aberration of Gravity in the Gravitational Light-Ray Deflection Experiments
- Kopeikin's new proposals for further improvements of the experimental results on the fundamental speed of gravity
Frontiers in Relativistic Celestial Mechanics. Vol. 1. Theory
- edited by S. Kopeikin
Frontiers in Relativistic Celestial Mechanics. Vol. 2. Applications and Experiments
- edited by S. Kopeikin
Relativistic Celestial Mechanics of the Solar System
- monograph by S. Kopeikin, M. Efroimsky and G. Kaplan
Metric Theories of Gravity: perturbations and conservation laws
- monograph by A. Petrov, S. Kopeikin, B. Tekin and R. Lompay {{DEFAULTSORT:Kopeikin, Sergei 1956 births Living people Russian physicists American physicists University of Missouri faculty Physicists from Missouri Scientists from Missouri University of Missouri physicists Moscow State University alumni Kopeikin, Sergie