Apparent Retrograde Motion of Mars
The planets orbiting the Sun farther than Earth’s orbit generally track slowly eastwards through the constellations as the months pass. For several weeks either side of the opposition, however, they appear to change direction and move westward, before later resuming their eastward track.
The period where they seem to move in reverse is called retrograde motion. It occurs because the faster-moving Earth overtakes a more distant planet, making it appear to move backwards against the stars. You might see a similar effect on the motorway when a car is overtaking a slower moving car—it appears to move backwards against the more distant scenery.
During this apparition, Mars moves in a retrograde motion from December 21st to March 10th, from six weeks before opposition and six weeks after opposition, before commencing its eastwards track towards the star Regulus.
- Client XplorePaks LLC.
- Date August 9, 2017
- Tags Illustration, Interactive
- URL View Project