In the year 1610, it was commonly believed that the Earth was the center of the Universe, that all bodies rotated around the perfect planet, placed by god with the heavens around it.  Galileo Galilei dealt a major blow to this idea, by using an early telescope to improve his vision and look up at some surprising dots. These dots formed a line that went straight through the bright planet Jupiter.  As Galileo looked again and again, night after night, he noticed that they not only persisted, they moved.  Their motion was predictable, and Galileo realized that they were orbiting Jupiter, just...