In this 4 part audio series about the discovery and nature of Mars’ orbit by Dr. Todd Young. In the concluding episode we hear about how Johannes Kepler’s contribution to the motion of Mars arguably sparked the origin of modern astronomy and science.

Listen to all 4 episodes – The Motion of Mars

The first episode describes how Mars will be spectacular in our night sky in the summer of 2018, as it outshines all the stars and planets except Venus. Listen to each episode in turn in the Science Around Us series.

Episode 2 explains how Mars periodically exhibits retrograde motion, where the planet moves east to west relative to the background stars instead of its more typical west to east motion. Understanding why this motion had been a challenge for hundreds of years.

Episode 3 describes Ptolemy presented a sophisticated mathematical model to explain why Mars and the other planets, moving around Earth, periodically moved retrograde relative to the background stars. This Earth-centered model of the universe presented what was imagined to be a true representation of the motion of Mars and the rest of the planets for over a millennium.

In episode 4 Dr. Young explains how Nicolaus Copernicus presented a heliocentric, or Sun-centered, model of the universe with the all the planets, including Earth and Mars, orbiting the Sun. However, Copernicus’ model was not well received because it did not predict the positions of the planets much better than Ptolemy’s geocentric, or Earth-centered, model, and religious influences during the time period also wanted to maintain that the Earth was the center of the universe.

That is, until our hero Kepler stepped in…