So what are these?

Events

1882 – Robert Koch announces the discovery of the bacterium responsible for tuberculosis (mycobacterium tuberculosis; seen above
in culture).

1965 – Ranger 9, equipped to convert its signals into a form suitable for showing on domestic television, brings images of the Moon into ordinary homes

Births

1490 – Georg Agricola, German scientist

1809 – Joseph Liouville, French mathematician

1820 – A. E. Becquerel, French physicist

1834 – John Wesley Powell, American explorer and environmentalist

1884 – Peter Debye, Dutch chemist, Nobel laureate

1893 – Walter Baade, German astronomer

1917 – John Kendrew, British molecular biologist, Nobel laureate

1936 – David Suzuki, Canadian environmentalist

1945 – Robert T. Bakker, American paleontologist

Deaths

1881 – Joseph Delesse, French geologist

1962 – Auguste Piccard, Swiss physicist and explorer

2002 – César Milstein, Argentine scientist, recipient of the Nobel Prize in Physiology or Medicine