Portrait of Galileo Galilei Courtesy of Ottavio Leoni, Reunion des Musees Nationaux

Galileo Galilei was an Italian astronomer and physicist who lived between 1564-1642. He challenged Aristotle's proposition that heavenly bodies were divine and therefore perfect and blemish-free.

Galileo was the first person to use a telescope to look at the heavens. He discovered sunspots, and craters and peaks in the moon. Galileo's work offended the Roman Catholic Church and he was sentenced to house arrest for the later years of his life. Today, he is remembered as a martyr for scientific truth.