Alexander Friedmann

This article is about the Russian cosmologist. For the Russian astrophysicist, seeAlexei Fridman.For the Polish Orthodox Jewish rabbi, seeAlexander Zusia Friedman.

In this name that followsEastern Slavic naming customs,thepatronymicisAlexandrovichand thefamily nameisFriedmann.

Alexander Friedmann
Александр Фридман
Born	Alexander Alexandrovich Friedmann (1888-06-16)June 16, 1888 Saint Petersburg,Russian Empire
Died	September 16, 1925(1925-09-16)(aged 37) Leningrad,Russian SFSR,Soviet Union
Nationality	Russian
Alma mater	St. Petersburg State University
Known for	Friedmann equations Friedmann–Lemaître–Robertson–Walker metric
Spouse	Natalia Malinina
Scientific career
Fields	Mathematicsandphysics
Institutions	Petrograd Polytechnical Institute Main Geophysical Observatory
Doctoral advisor	Vladimir Steklov
Doctoral students	George Gamow Nikolai Kochin Pelageya Polubarinova-Kochina
Signature

Alexander Alexandrovich Friedmann(also spelledFriedmanorFridman;/ˈfriːdmən/;Russian:Алекса́ндр Алекса́ндрович Фри́дман;June 16 [O.S.June 4] 1888 – September 16, 1925) was a Russian and Sovietphysicistandmathematician.He originated the pioneering theory that theuniverse is expanding,governed by a set of equations he developed known as theFriedmann equations.

Early life

Alexander Friedmann was born to the composer and ballet dancer Alexander Friedmann (who was a son of a baptizedJewishcantonist) and the pianist Ludmila Ignatievna Voyachek (who was a daughter of the Czech composer Hynek Vojáček).Friedmann was baptized into theRussian Orthodox Churchas an infant, and lived much of his life inSaint Petersburg.

Friedmann obtained his degree fromSt. Petersburg State Universityin 1910, and became a lecturer atSaint Petersburg Mining Institute.

From his school days, Friedmann found a lifelong companion inJacob Tamarkin,who was also a distinguished mathematician.

World War I

Friedmann fought inWorld War Ion behalf ofImperial Russia,as an army aviator, an instructor, and eventually, under the revolutionary regime, as the head of an airplane factory.

Professorship

Friedmann in 1922 introduced the idea of an expanding universe that contained moving matter. Correspondence with Einstein suggests that Einstein was unwilling to accept the idea of an evolving Universe and worked instead to revise his equations to support the static, eternal Universe of Newton's time. In 1929 Hubble published theredshift vs distance relationshipshowing that all the galaxies in the neighborhood recede at a rate proportional to their distance, formalizing an observation made earlier byCarl Wilhelm Wirtz.Unaware of Friedmann's work, in 1927BelgianastronomerGeorges Lemaîtreindependently formulated an evolving Universe.

In June 1925 Friedmann was given the job of the director of the Main Geophysical Observatory in Leningrad. In July 1925 he participated in a record-setting balloon flight, reaching the elevation of 7,400 m (24,300 ft).

Work

Friedmann's 1924 papers, including "Über die Möglichkeit einer Welt mit konstanter negativer Krümmung des Raumes"(" On the possibility of a world with constant negative curvature of space ") published by the German physics journalZeitschrift für Physik(Vol. 21, pp. 326–332), demonstrated that he had command of all three Friedmann models describing positive, zero and negative curvature respectively, a decade beforeRobertsonandWalkerpublished their analysis.

This dynamiccosmologicalmodel ofgeneral relativitywould come to form the standard for both theBig BangandSteady Statetheories. Friedmann's work supported both theories equally, so it was not until the detection of thecosmic microwave background radiationthat the Steady State theory was abandoned in favor of the current favorite Big Bang paradigm.

The classicsolutionof the Einstein field equations that describes a homogeneous and isotropic universe was called theFriedmann–Lemaître–Robertson–Walker metric,orFLRW,after Friedmann,Georges Lemaître,Howard P. RobertsonandArthur Geoffrey Walker,who worked on the problem in the 1920s and 30s independently of Friedmann.

In addition to general relativity, Friedmann's interests includedhydrodynamicsandmeteorology.

PhysicistsGeorge Gamow,Vladimir Fock,and Lev Vasilievich Kellerwere among his students.

Personal life and death

Friedmann's Grave atSmolensky Cemetery,Saint-Petersburg.

In 1911, he married Ekaterina Dorofeeva, though he later divorced her. He married Natalia Malinina in 1923. They had a religious wedding ceremony, though both were far from religious.Together they had a son Alexander Alexandrovich Friedman (1925—1983), born after his father's death.

Friedmann died on September 16, 1925, from misdiagnosedtyphoid fever.He had allegedly contracted the bacteria on return from his honeymoon inCrimea,when he ate an unwashed pear bought at a railway station.

Legacy

The Moon craterFridmanis named after him.

Alexander Friedmann International Seminar is a periodical scientific event. The objective of the meeting is to promote contact between scientists working in the field of Relativity, Gravitation and Cosmology, and related fields. The First Alexander Friedmann International Seminar on Gravitation and Cosmology devoted to the centenary of his birth took place in 1988.

During the2022 COVID-19 protests in China,Tsinghua Universitystudents were seen displaying Friedmann's equation as if it were a protest slogan, which was understood as anevasion of censorshipby punning multilingually on "free man" and referring to liberalization and opening via the expansion of the universe.

Selected publications

• Friedman, A. (1922). "Über die Krümmung des Raumes".Zeitschrift für Physik.10(1): 377–386.Bibcode:1922ZPhy...10..377F.doi:10.1007/BF01332580.S2CID125190902..English translation in:Friedman, A. (1999). "On the curvature of space".General Relativity and Gravitation.31(12): 1991–2000.Bibcode:1999GReGr..31.1991F.doi:10.1023/A:1026751225741.S2CID122950995.The original Russian manuscript of this paper is preserved in theEhrenfest archive,together with some letters and unpublished work.
• Friedman, A. (1924). "Über die Möglichkeit einer Welt mit konstanter negativer Krümmung des Raumes".Zeitschrift für Physik.21(1): 326–332.Bibcode:1924ZPhy...21..326F.doi:10.1007/BF01328280.S2CID120551579..English translation in:Friedmann, A. (1999). "On the Possibility of a World with Constant Negative Curvature of Space".General Relativity and Gravitation.31(12): 2001–2008.Bibcode:1999GReGr..31.2001F.doi:10.1023/A:1026755309811.S2CID123512351.

Bibliography

• Poluboyarinova-Kochina, P. Ya. (January–February 1964)."Aleksandr Fridman"(PDF).Soviet Physics Uspekhi (English Edition):467–472.
• Ferguson, Kitty (1991).Stephen Hawking: Quest For A Theory of Everything.New York:Bantam Books.ISBN0-553-29895-X.
• Frenkel', V.Ya. (1988). "Aleksandr Aleksandrovich Fridman (Friedmann): a biographical essay".Soviet Physics Uspekhi.31(7): 645–665.Bibcode:1988SvPhU..31..645F.doi:10.1070/PU1988v031n07ABEH003574.

External links

• Alexander A Friedmann: The Man who Made the Universe Expand– Biography written by Eduard A. Tropp, Viktor Ya. Frenkel and Artur D. Chernin
• O'Connor, John J.;Robertson, Edmund F.,"Alexander Friedmann",MacTutor History of Mathematics Archive,University of St Andrews
• How Do We Know the Age of the Universe– Mary Lynn Germadnik