An Italian astronomer (1564-1642) and physicist associated with many of the important advances in science in the late Middle Ages.

Galileo made major investigations in the fields of mechanics, including experiments on acceleration, friction, inertia, and falling bodies.

He is credited with improving the telescope and pioneered its use for astronomical observations, discovdering mountains on the moon, many new stars, the four satellites of Jupiter, and the composition of the Milky Way.

He also supported the theories of Copernicus concerning the motions of the planets.