- 1610: Galileo
- 1676: Ole Rømer
- 1687: Isaac Newton
- 1781: William Herschel
- 1838: Friedrich Bessel
- 1861: William and Margaret Huggins
- 1912: Henrietta Leavitt
- 1917 Einstein
- 1920: Harlow Shapley
- 1929 Edwin Hubble
- 1948: Ralph Alpher
- 1949: Fred Hoyle
- 1963: Maarten Schmidt
- 1964: Arno Penzias and Robert Wilson
- 1978: Vera Rubin and Kent Ford
- 1989: Margaret Geller and John Huchra
- 1992: John Mather and George Smoot
- 1995: Robert Williams
- 1998: Saul Perlmutter and Brian Schmidt
- 2010: Wendy Freedman

# Alexander Friedmann

Alexander Friedmann |

Ignoring the cosmological constant as an unnecessary “fudge factor,” Friedmann solved Einstein’s dilemma of how to account for the fact that the universe had not already collapsed by supposing that it began with an initial expansion, and that the effect of gravity would be to gradually slow the expansion. He predicted that if there were enough mass in the universe the expansion would eventually reverse; while if the mass were too little the universe would continue to expand forever. And if the amount of mass were just right the expanding universe would slow down and come to a virtual standstill, neither collapsing further nor infinitely expanding.