Alexander Friedmann was born to the composer and ballet dancer Alexander Friedmann and the pianist Ludmila Ignatievna Voyachek. Friedmann was baptized into the Russian Orthodox Church as an infant, and lived much of his life in Saint Petersburg. Friedmann obtained his degree from St. Petersburg State University in 1910, and became a lecturer at Saint Petersburg Mining Institute. From his school days, Friedmann found an inseparable companion in Jacob Tamarkin, who at the end of his career was one of Brown University's most distinguished mathematicians.
Friedmann fought in World War I on behalf of Imperial 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 modify his equations to ensure a static eternal Universe as believed from Newton's time. Some years later, in 1926 Hubble published the redshift vs distance relationship, namely, all the galaxies in the neighborhood seemed to be receding at a rate proportional to their distance, formalising an observation made earlier by Carl Wilhelm Wirtz. It may be noted that in 1927 Belgian astronomer Georges Lemaître also independently reached the conclusion of an evolving Universe. In June 1925 Friedmann was given the job of the director of Main Geophysical Observatory in Leningrad. In July 1925 he participated in a record-setting balloon flight, reaching the elevation of.
Work
Relativity
Friedmann's 1924 papers, including "Über die Möglichkeit einer Welt mit konstanter negativer Krümmung des Raumes" published by the German physics journalZeitschrift für Physik, demonstrated that he had command of all three Friedmann models describing positive, zero and negative curvature respectively, a decade before Robertson and Walker published their analysis. This dynamic cosmological model of general relativity would come to form the standard for both the Big Bang and Steady State theories. Friedmann's work supports both theories equally, so it was not until the detection of the cosmic microwave background radiation that the Steady State theory was abandoned in favor of the current favorite Big Bang paradigm. The classic solution of the Einstein field equations that describes a homogeneous and isotropic universe is called the Friedmann–Lemaître–Robertson–Walker metric, or FLRW, after Friedmann, Georges Lemaître, Howard P. Robertson and Arthur Geoffrey Walker, who worked on the problem in 1920s and 30s independently of Friedmann.
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.
Death
Friedmann died on September 16, 1925 from misdiagnosed typhoid fever. He had allegedly contracted the bacteria on his way back from his honeymoon in Crimea when he ate an unwashed pear he bought from a railway station.
Alexander Friedmann International Seminar is a periodical scientific event. The objective of the meeting is to promote contacts 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.
Selected publications
. English translation in: The original Russian manuscript of this paper is preserved in the , together with some letters and unpublished work.
