Portrait of Galileo Galilei, 1624, by Ottavio Leoni

February 15, 1564 - Galileo Galilei's birthday

An Italian physicist and astronomer,
Galileo was a strong proponent of Copernican heliocentrism (see February 19),
the theory that the Sun is at the center of the Solar System.
At the time, most people believed the Earth was the center of the universe.