Alexander Friedmann, born 16 June 1888

[michael8554]

Alexander Alexandrovich Friedmann, Russian mathematician, born on 16 June, 1888 (died 16 September, 1925).  

He 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 June 1922, he showed that the radius of curvature of the universe can be either an increasing or a periodic function of time. 

Reference:

 http://www.springerreference.com/docs/html/chapterdbid/58487.html

 http://fineartamerica.com/featured/alexander-friedman-soviet-cosmologist-ria-novosti.html

 http://jonrfriedman.com/index.php?album=Portraits/Published%20Portraits/the-astronomers-universe&image=Alexander-Alexandrovich-Friedmann-1888-1925.jpg