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.