1965 – Kecksburg UFO incident: A fireball is seen from Michigan to Pennsylvania; with witnesses reporting something crashing in the woods near Pittsburgh.
1979 – The eradication of the smallpoxvirus is certified, making smallpox the first of only two diseases that have been driven to extinction (with rinderpest in 2011 being the other).
2016 – President Park Geun-hye of South Korea is impeached by the country's National Assembly in response to a major political scandal.
2016 – At least 57 people are killed and a further 177 injured when two schoolgirl suicide bombers attack a market area in Madagali, Adamawa, Nigeria in the Madagali suicide bombings.
^A. Fresnel, "Mémoire sur la double réfraction que les rayons lumineux éprouvent en traversant les aiguilles de cristal de roche suivant les directions parallèles à l'axe", read 9 December 1822; printed in H. de Senarmont, E. Verdet, and L. Fresnel (eds.), Oeuvres complètes d'Augustin Fresnel, vol. 1 (1866), pp. 731–51; translated as "Memoir on the double refraction that light rays undergo in traversing the needles of quartz in the directions parallel to the axis", Zenodo: 4745976, 2021 (open access).
^Torrey, Glenn E. (1989), "Romania Leaves the War: The Decision to Sign an Armistice, December 1917", East European Quarterly, vol. 23, no. 3, pp. 283–292
^Fisher, Catherine Horne. "Irene Adelaide Greenwood (1898–1992)". Greenwood, Irene Adelaide (1898–1992). National Centre of Biography, Australian National University. Retrieved 9 January 2020. {{cite book}}: |website= ignored (help)
^King, Amy C.; Schalch, Tina (1987). "Grace Brewster Murray Hopper". In Grinstein, Louise S.; Campbell, Paul J. (eds.). Women of Mathematics: a Biobibliographic Sourcebook. New York: Greenwood Press. p. 67. ISBN978-0-3132-4849-8.