The Inner Planets: The Moving Planets

The video explores the evolution of astronomical theories, starting with the belief that the Sun revolved around the Earth. Copernicus introduced the heliocentric model, suggesting that planets orbit the Sun. Kepler later refined this model, proposing that planets move in elliptical orbits. The concept of an ellipse is explained, likening it to an oval shape. Newton's laws of motion and the force of gravity are discussed, explaining why planets maintain their orbits around the Sun.

What did Nicolaus Copernicus propose about the structure of the solar system?

How did Johannes Kepler's theories differ from those of Copernicus?

Define an ellipse and explain its significance in planetary orbits.

What principle did Isaac Newton introduce to explain the motion of planets?

Explain how gravity affects the motion of planets in their orbits.