KEPLER

Johannes Kepler was a mathematician, astronomer, and astrologer. He was a key figure in 1700's science evolution. He had three laws of planetary motion:
1. All planets move in an elipse around the sun
2. The closer a planet is to the sun, the faster it orbits. When a planet is further away from the sun it moves slower.

3. The larger the elliptical orbit, to slower it takes a planet to complete one orbit.
When a planet moves in an opposite direction it's called "Retro Grade." Planets that move in Retro Grade also do epicycles. An epicycle is a when a planet moves in a circle.
We still use these laws today in astrology. We're even still discovering new things about the universe. Kepler was a pioneer in astronomy!