It is this region in which the Earth overtakes Mars that we get retrograde motion. Using a heliocentric model makes for a simple explanation of the retrograde motion of Mars.

To read more about the heliocentric model, and to learn about retrograde motion, visit this page at the Penn State University College of Earth and Mineral Sciences website.

"The explanation for retrograde motion in a heliocentric model is that retrograde occurs roughly when a faster moving planet catches up to and passes a slower moving planet," StarChild explains.

In the 16th century, Copernicus revived interest in Aristarchus’s heliocentric ideas, noting that the most puzzling aspect of planetary motion, the periodic “retrograde” motion of the ...

This can explain retrograde motion, but his model doesn't fit all the planetary position data that well. ... But still, this IS evidence of a heliocentric model that you can figure out for yourself.

Today, I wanted to talk about the history of the heliocentric model. After all, Copernicus’ most notable accomplishment is probably his proposed heliocentric, or sun-centered, model for the ...

Retrograde motion has captured sky-gazing humans’ attention for millennia. ... the heliocentric model caught on—which, “for many people, ...