Learn about the history of science by reading about the significant scientific events that took place on this day in history.
1997 - Clyde William Tombaugh died.
Tombaugh was an American astronomer who discovered the dwarf planet Pluto while searching for Percival Lowell and William Pickering's Planet X that would explain the orbit of Neptune. He also discovered 14 asteroids. Tombaugh claimed he observed lights near Las Cruces, New Mexico he claimed were UFOs.
1946 - Clarence E. McClung died.McClung was an American biologist who discovered chromosomes determine the sex of a species. He also researched the effect of chromosomes had on heredity.
1938 - William Henry Pickering died.
Pickering was an American astronomer who discovered Phoebe, the ninth moon of Saturn. He believed he had discovered a tenth moon and named it Themis, but his moon turned out to be artifacts on the photographic plates. He also searched for "Planet X", a planet that he predicted to be outside the orbit of Neptune that caused perturbations in the orbits of Uranus and Neptune.
1911 - Francis Galton died.
Galton was an English polymath who is best known for his early work in eugenics or the selection of parents to increase beneficial traits into their offspring. He also proposed the use of fingerprints as a unique identifier of individuals and developed the classification system still in use today.
1910 - Friedrich Wilhelm Georg Kohlrausch died.
Kohlrausch was a German physical chemist who focused on the thermal, electrical and magnetic properties of electrolytes. Electrolytes are substances that conduct electricity in solutions through the transfer of ions. He was the first to demonstrate electrolytes have a constant electrical resistance and measured the velocities of the transferred ions for a particular electrolyte.