Portal:History of science/Selected anniversaries/October 30
- 1626 – Death of Willebrord Snell, Dutch astronomer and mathematician (b. 1580)
- 1844 – Birth of Harvey W. Wiley, American chemist (d. 1930)
- 1847 – Birth of Galileo Ferraris, Italian physicist (d. 1897)
- 1857 – Birth of Georges Gilles de la Tourette, French neurologist (d. 1904)
- 1900 – Birth of Ragnar Granit Finnish neuroscientist, Nobel laureate (d. 1991)
- 1909 – Birth of Homi J. Bhabha, Indian physicist (d. 1966)
- 1939 – Birth of Leland H. Hartwell, American scientist, Nobel laureate
- 1941 – Birth of Theodor W. Hänsch, German physicist, Nobel laureate
- 1961 - Nuclear testing: The Soviet Union detonates the hydrogen bomb Tsar Bomba over Novaya Zemlya; at 58 megatons of yield, it is still the largest explosive device ever detonated, nuclear or otherwise. Nikita Khrushchev announces that the scientists had planned to make it 100 megatons, but had reduced the yield to reduce fallout over the Soviet Union
- 1975 – Death of Gustav Ludwig Hertz, German physicist, Nobel Prize laureate (b. 1887)
- 1979 – Death of Sir Barnes Wallis, British scientist, engineer and inventor (b. 1887)
- 2002 - British Digital terrestrial television (DTT) Service Freeview begins transmitting in parts of the United Kingdom