In the Beginning

This series is about not just what we know, but how we know it, and who figured it out. In this first episode, we begin by looking at what primitive humans thought of the universe. Most civilizations believed the earth below us was flat, with the solid, domed sky arching over us. They noticed the repetitive motions of the sun and stars and used them to create a calendar and predict the seasons. But the planets, with their erratic motions, remained a mystery.