I’ve read that it means it appears to be going backwards but does it?
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Retrograde refers to when the movement of planets in the sky appears to reverse.
This is the result of our planets orbit. When Earth gets to the closest point to another planet like mars, Mars will appear to move backwards in the sky for a bit.
There are numerous GIFs and animations online that detail this effect
Imagine you’re watching two cars race around a big circle. One car is super fast, and the other one is slower. But here’s the tricky part: the fast car is on a smaller circle inside the big one.
As you watch them, there are times when the super-fast car zips past the slower one. When that happens, it might look like the slower car is going backward, even though it’s not. It’s like a race where the speedy car does a loop and tricks your eyes into thinking the other car is going in reverse.
Key idea here: on any given night, if you watch a planet, it will rise in the east and set in the west, appearing to be motionless relative to the stars around it. It will never appear to rise in the west and set in the east.
If you compare the planet’s location relative to the stars and come out night after night, you will typically see that each night, its position has moved a little bit to the east. This is how we noticed the planets were different from the stars.
When a planet is in retrograde, if you come out each night, you will notice that each night it’s a little farther to the west instead of east. The slow night-to-night changes are backward compared to the usual motion.
Again, though, the motion you see during the course of a single night will always be east-to-west, moving right along with the stars around it.
If you assume that the Earth is the center of the cosmos, then yes, planets appear to periodically reverse direction and then continue on their previous path, unlike other celestial objects like stars, the sun, and the moon, which trace straightforward arcs across the sky. During those times, the planet is said to be in “apparent retrograde motion.”
Of course, we know now that this is because the planets are not orbiting the Earth, but because they are orbiting the Sun, which is orbiting the Earth (from our perspective). But back in ancient times it was very confusing, and people often attached great significance to the apparent motion.
[Here’s a neat picture.](https://earthobservatory.nasa.gov/ContentFeature/OrbitsHistory/images/retrograde_mars_tezel_2007-2008.jpg)
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