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 goes around Earth.
This seemed very clear to most people. Not many even questioned the idea. Then, in 1543, Polish astronomer Nicolaus Copernicus had a new idea. He said that Earth actually traveled around the Sun. For decades, people tried to say if he was right or wrong. The telescope became key to finding the answer. Telescopes have since become more high-tech. They have taken our knowledge beyond Copernicus’s dreams.