There’s a lot of buzz around this topic in the astrology world, especially with planet Mercury. To be very clear: planets in retrograde are not actually spinning backwards – it is entirely an optical illusion as seen from Earth. Backwards motion appears to be happening when Earth passes slower moving planets in the outer solar system. This happens with every single celestial body in our solar system except the Sun and Moon (as seen from Earth).
This phenomenon can be tested on the highway while driving. Say you are passing a slower car. You pull up alongside the car, and then the car seems to move backwards for a few moments. After passing the car completely, it returns to forward motion. Of course the car was moving forward the entire time, but your perspective allowed for the illusion of backwards motion. This is exactly what happens on Earth in relation to other celestial bodies at certain times of the year. In astrology, this illusion manifests as a sort of “backwards” functioning of the planets and their roles.
There are a few plausible interpretations for natal planets in retrograde. Most people have at least one planet retrograde at the time of birth, others may have up to four or five. The more planets in retrograde, the more likely this person is to be a late bloomer. One might also say that retrograde planets in the natal chart mean that this person will encounter more obstacles and challenges early in life that then help them to become wiser and more successful in later years. Maybe these theories are interconnected, one and the same.