People thought about the stars long before we had telescopes. Greek scientists such as Aristotle (384–322 B.C.) and Ptolemy (A.D. 100–165) said that the Sun traveled around Earth.
This seemed so clear that few questioned it. Then, in 1543, Polish astronomer Nicolaus Copernicus said that Earth actually traveled around the Sun. For many decades, people tried to prove him right or wrong. The telescope was the key to finding the answer. Telescopes have become more sophisticated since then. They have expanded our knowledge beyond Copernicus’s dreams.
