(1564-1642AD)
Born in Italy, Galileo Galilei was a major contributor to the human understanding of astronomy. This is because he was the inventor of the telescope, the first person to hold a lens towards the sky. This opened up an entirely new world of discovery for Galileo.
Using his telescope, Galileo proved Copernicus' theory of a heliocentric universe, and that the planets orbit around it. But the church at the time did not take lightly to Galileo's discovery, and Galileo was convicted of heresy and sentenced to house arrest.
Galileo's major findings are listed as: the moon does in fact have phases (meaning it is orbiting the Earth). The universe is heliocentric (sun centered), and the planets and stars are not perfect.
Galileo's telescope, the first of its kind, he used this to make startling discoveries in space.
