From Wikipedia, the free encyclopedia
June 21
- 1646 (O.S.) - birth of Gottfried Wilhelm Leibniz, German philosopher and scientist (d. 1716)
- 1781 - birth of Siméon-Denis Poisson, French mathematician and physicist (d. 1840)
- 1805 - birth of Charles Thomas Jackson, American scientist, polymath (d. 1880)
- 1811 - birth of Carlo Matteucci, Italian physicist (d. 1868)
- 1823 - birth of Jean Chacornac, French astronomer (d. 1873)
- 1828 - birth of Ferdinand André Fouqué, French geologist (d. 1904)
- 1870 - birth of Clara Immerwahr, German chemist (d. 1915)
- 1874 - death of Anders Jonas Ångström, Swedish physicist (b. 1814)
- 1876 - birth of Willem Hendrik Keesom, Dutch physicist (d. 1956)
- 1887 - birth of Norman L. Bowen, Canadian petrologist (d. 1956)
- 1898 - birth of Donald C. Peattie, American botanist and writer (d. 1964)
- 1918 - birth of James Clyde Mitchell, English sociologist and anthropologist
- 1951 - death of Charles Dillon Perrine, American astronomer (b. 1867)
- 1957 - death of Johannes Stark, German physicist, Nobel Prize laureate (b. 1874)
- 2004 - civilian space ship SpaceShipOne is launched, reaching an altitude of 100 km (62.5 miles), just passing the edge of space.
