When1: 1918
When2: 1922
Who: Alexander Friedmann [Friedmann, Alexander]
What: physicist
Where: Germany
Detail: He lived 1888 to 1925 and mathematically demonstrated that general relativity required expanding universe [1918]. He imagined universes {Friedmann space-time} that had uniform matter and energy, expanded forever, were infinite, and had no boundary [1922]. Howard Robertson and Arthur G. Walker [1936] elaborated {Friedmann-Robertson-Walker space-time} {FRW universe}, because universe is like FRW universe.
Physical Sciences>Physics>History>Cosmology
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Date Modified: 2022.0224