Be an astronomer for a day! Learn the individual properties of the Earth, Moon and Sun, what causes day and night, the 4 seasons, moon phases and the tides. Learn how the NASA Apollo Missions greatly increased our understanding of the Moon. Learn about famous astronomers (Aristotle, Ptolemy, Copernicus and Galileo) and how they contributed to our understanding of the universe today. Our lessons and flashcards are developed using concepts and information that are universal in nature and applic