Portal:History of science/Selected anniversaries/October 27
- 1675 – Death of Gilles de Roberval, French mathematician (b. 1602)
- 1904 - The first underground New York City Subway line opens; the system becomes the biggest in United States, and one of the biggest in world
- 1921 – Birth of Warren Allen Smith, American encyclopedist
- 1953 - British nuclear test Totem 2 is carried out at Emu Field, South Australia
- 1968 – Death of Lise Meitner, German physicist (b. 1878)
- 1980 – Death of John Hasbrouck van Vleck, American physicist, Nobel Prize laureate (b. 1899)
- 1992 – Death of David Bohm, American-born physicist, philosopher, and neuropsychologist (b. 1917)
- 1999 – Death of Robert Mills, American physicist (b. 1927)