Early Astronomers

Copernicus' heliocentric model places
the Sun in the center of the universe

Astronomy is one of the oldest sciences. Prehistoric cultures left behind astronomical artifacts. The cultures of the earliest people created temples and monuments to show that the skies had a role in their lives.  Ancient Greeks studied the movement of objects in the night sky to construct their view of the universe.

As time moved into the Renaissance, the thoughts on where Earth was located in the universe began to change. It was Ptolemy, who suggested in the second century, that the Earth was situated in the center of the universe.  A new age of astronomical thinking began when Copernicus placed the Sun at the center of the universe. This new development created a wave of astronomical observations as scientists like Brahe, Kepler, Galileo, and Newton all added ideas as to how planets orbit the Sun.

As you study the history of astronomy, notice the following two themes: the struggle to understand the placement of Earth in the universe and the struggle to understand planetary motion. As time passed, the use and reliance on technology subsequently increased, and so did the accuracy in predicting how the planets travel around the Sun.

Essential Questions

• What ideas did early astronomers have about the movement of the solar system?
• What are Kepler’s Laws of Planetary Motion?
• What are Newton’s Laws of Motion?