The year 1669 in science and technology included many events, some of which are listed here.

See also: 1668 in science, other events of 1669, 1670 in science and the list of years in science.

Astronomy

• Montanari detects the variability of the eclipsing binary Algol

Geology

• Nicolas Steno puts forward his theory that sedimentary strata had been deposited in former seas, and that fossils were organic in origin

Births

Deaths