Galileo Demonstrates the Telescope
Galileo Galilei made a good discovery great. Upon hearing at age 40 that a Dutch optician had invented a glass that made distant objects appear larger, Galileo crafted his own telescope and turned it toward the sky . Galileo quickly discovered that our Moon had craters , that Jupiter had it's own moons , that the Sun has spots , and that Venus has phases like our Moon . Galileo , who lived from 1564 to 1642, made many more discoveries. Galileo claimed that his observations only made sense if all the planets revolved around the Sun , as championed by Aristarchus and Copernicus , not the Earth , as was commonly believed then. The powerful Inquisition made Galileo publicly recant this conclusion , but today we know he was correct.