Faced with this problem, and a good two thousand years before the invention of the telescope, Aristarchus of Samos (310 BC – 230 BC) wrote On the Sizes and Distances of the Sun and Moon. In this book, Aristarchus posited that the sun, not the earth, was the center of the solar system. Even though he was right, and he was looking at the same night sky as all the philosophers and astronomers that came before him and after him, his teachings were summarily ignored for approximately 2000 more years. But why was Aristarchus able to see things that were invisible to everyone else? He was not super human. Nor did he have extraordinary vision or even a telescope. Visual observations were rejected in favor of spiritual and religious beliefs of the day. Thus, for thousands of years, humans were blind to what their visual observations and mathematical calculations told them.