These words of Galileo Galilei appear early in the book, Galileo's Daughter by Dava Sobel. Think of the feeling Galileo must have had when he became the first person ever to see the valleys and mountains of the moon, the dark masses of sunspots moving across the face of the sun, and the moons, (which he referred to as planets), of Jupiter. Imagine living in a world with no concept of gravity, with no true common understanding of the physical make-up of your own planetary system or even of your own body. A few years before Galileo's telescope, Copernicus used mathematics and his own genius to posit a sun-centered universe. Soon after, Galileo looked through his telescope to reveal the truth, unpopular though it was at the time. What bravery it takes to speak the truth to people who don't want to hear it. Out of the darkness of centuries of common ignorance, a few men intuited, and some later proved, truths that were once believed to be only the province of the gods.