There are two planets which are exceptions and never seem to retrograde.
- The Sun never retrogrades because it is truly the center of our solar system. Since our orbital direction around the Sun never changes, it always appears to be moving in Direct or forward motion.
- The Moon also never retrogrades, since we are the center of its orbit. Since it always moves around Earth in one direction, we never see it appear to move backwards.
All the other planets will periodically appear to retrograde. In the case of the planets inside our orbit (Mercury and Venus), this is because we see them reach the longitudinal maximum extent of their orbits, which is a point in the orbit perpendicular to our line-of-sight to the Sun, then swing inside of and begin to cross in front of the Sun.
While these two planets are inside of this 3-9 Line (so called because it's a line through the 3 o'clock and 9 o'clock positions), they will appear to retrograde, or move backwards. A simple animation will help to make this clear.
| Illustration of Inner Planet Retrogradation |
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The planets outside of our orbit also appear to retrograde, although they do so for a different reason. Since they're further away from the Sun than we are, they move slower than we do. As we catch them and pass them, they appear to move backwards just as a slower-moving vehicle appears to move backwards when we pass them on the freeway. Again, an ainmation will help to clarify why this happens.
| Illustration of Outer Planet Retrogradation |
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Astrologically, a retrograde planet is symbolically retracing ground that has already been covered. Wherever one finds a retrograde planet, it seems to indicate a need to internalize that planet's energies, come to terms with them, and "own" them. A retrograde planet in the birth chart will not usually express itself in the conventional way, but will often seem less overt. However, it has been my experience that it will often express itself in an unconscious way. That means that when it is overtly seen, it appears undeveloped, raw, primative, and not wholly under the conscious control of the native.