Ages

Introduction

Summary

Mars's trajectory seems to go backward periodically. This is called a retrogradation (or retrograde motion). Because the Earth orbits 1.88 times faster than Mars, the relative motion of both explains this phenomenon.
The animation is not drawn to scale, for either sizes or distances.
The frame of reference here is heliocentric. See the animation  " Retrograde Motion #2" for the geocentric point of view.

Goals

• To understand the retrograde motion of mars.
• To understand why the distance between Earth and Mars varies periodically.

Features

Click on to stop the motion.

Tags

retrograde motion mars orbit celestial retrogradation earth sun