When you look at the traits and appearances of the planets, it can be easy to see where astrology found the symbolism to assign to each planet… so let’s roll through them for some simple examples.
The Sun is the center of any birth chart, and the center of our solar system. The light of the Sun gives life. Without the sun we would not “see” anything and so we “see” the world filtered through the light of our Sun Sign. All the other planets will tweak and fine-tune your personality, but you are your Sun Sign.
The Moon is the second most noticeable object in the sky, and the most changeable, and it was assigned to our changeable emotions. And the moon is often the only available light at night, so it connects to the subconscious, and where we return to at night: home. Add in a monthly cycle roughly analogous to the human female reproductive cycle and you can see why the Moon is connected to mother, too.
Mercury is fast; zipping around, backing up 3x a year, and closely circling the Sun, never more than one sign away. It symbolizes thinking, the mind, talking, communication, local travel, the immediate neighborhood, electricity and the nervous system.
Venus is the closest planet to Earth, so it is about close relationships, marriage, partners. Often referred to as one of the most beautiful sights in the sky, it also is associated with comfort, beauty & art.
Mars is red, even to the naked eye. Red = anger, action, fire, sharp objects, fevers & infections. And it connects to the physical side of sexual relationships.
Jupiter is the biggest planet. It is aligned with expansion, growth, higher education & justice, good fortune, and optimism. The word “jovial” is an adjective for a good-natured happy person, and its word root is from Jupiter.
Saturn is the second largest of the original “known” planets but it has rings around it, holding it back. Saturn is connected to restrictions, focus, responsibility, cutting back and limitations. And since “Dad” was traditionally the family member who went out into the world, and was responsible for the practical things a family needs, Saturn can be tied to the father.
Then, as each new planet was discovered, astrologers related them to the times they were discovered.
Uranus was found during an era of revolution (American, French, etc)… when kings were getting replaced with a new form of government by the people… so it is connected to sudden change, surprise, freedom and individual rights. Also, just to be weird, it rolls around sideways compared to the other planets. All the others rotate upright, with a north & south pole? Uranus revolves around the sun spinning on its side! No wonder it is associated with individualism & the unique.
True to Neptune’s vague, misty, uncertain, spiritual side, two different people discovered it twice, decades apart. And it turned up in the 1800s during the Second Great Awakening, when new religions sprung up, and spirituality was on the rise… and it is the planet of spirituality, vagueness, fantasy, confusion and lies, drugs & alcohol.
Pluto, still considered a planet by astrologers, was discovered in the 1930s, during the rise of psychiatry and the discovery of nuclear energy… so it is related to deep, strong, dominating and/or transforming power.
Now, when you look at your own chart, take the traits above and consider how they might be expressed through the nature of that planet’s sign. Planets symbolize the actions we take, and the signs they are in symbolize how we take those actions. This is one of the first steps in interpreting a birth chart.