Portal:History of science/Selected anniversaries/December 28
- 1612 - Galileo Galilei becomes the first astronomer to observe the planet Neptune, although he mistakenly catalogued it as a fixed star
- 1663 - Death of Francesco Maria Grimaldi, Italian mathematician and physicist (b. 1618)
- 1708 - Death of Joseph Pitton de Tournefort, French botanist (b. 1656)
- 1795 - Death of Eugenio Espejo, Ecuadorian scientist (b. 1747)
- 1882 - Birth of Arthur Stanley Eddington, British astronomer (d. 1944)
- 1898 - Birth of Carl-Gustaf Rossby, Swedish meteorologist (d. 1957)
- 1903 - Birth of John von Neumann, Hungarian-born mathematician (d. 1957)
- 1919 - Death of Johannes Rydberg, Swedish physicist (b. 1854)
- 1944 - Birth of Kary Mullis, American chemist, Nobel laureate
- 1981 - The first American test-tube baby, Elizabeth Jordan Carr, is born in Norfolk, Virginia
- 2001 - Death of Samuel A. Goldblith, American food scientist (b. 1919)