Alexander Alexandrovich FriedmannBorn 16 Jun 1888; died 16 Sep 1925 at age 37.Russian mathematician who was the first to work out a mathematical analysis of an expanding universe consistent with general relativity, yet without Einstein's cosmological constant. In 1922, he developed solutions to the field equations, one of which clearly described a universe that began from a point singularity, and expanded thereafter. In his article On the Curvature of Space received by the journal Zeitschrift für Physik on 29 Jun 1922, he showed that the radius of curvature of the universe can be either an increasing or a periodic function of time. In Jul 1925, he made a record-breaking 7400-m balloon ascent to make meteorological and medical observations. A few weeks later he fell ill and died of typhus.[Also spelled Aleksandr Aleksandrovich. Last name also seen as Friedman. For date of birth, see MacTutor for explanation of why 17 Jun or 29 Jun birthdate seen in various sources is due to a confusion between New Syle and Old Style dates. Birth date is 29 Jun 1888 Old Style.] |
