It wasn't till Huygens had two things: He had a good theory of planetary rings and how the solar system operated, and he had better telescopic, more fine-grain data in which he could figure out that as the Earth is going around faster — according to Kepler's Laws — than Saturn, then we catch up with it.
No fue sino hasta que Huygens tuvo dos cosas: Una buena teoría de anillos planetarios y de cómo operaba el sistema solar, y mejores telescopios, mejores datos.