Imagine the Universe!

Kepler's Laws I, II, and III

Johannes Kepler (1571-1630) was a German astronomer and mathematician. He was the first to understand that the planets in our solar system move in ellipses, not circles. He then continued his investigations, finally arriving at three principles of planetary motion. Known as Kepler's Laws, these principles revolutionized planetary astronomy. Many years after Kepler, Sir Isaac Newton proved that all three of Kepler's Laws are a direct result of the laws of gravitation and physics which govern the forces at work between various massive bodies.

Kepler's First Law

Kepler's Second Law

More about Kepler's Second Law

Kepler's Third Law



The Imagine Team
Project Leader: Dr. Barbara Mattson
Curator: J.D. Myers
Responsible NASA Official: Phil Newman