## Revolutionibus and Scandal
### The Copernican System
In school you probably learned of the Copernican system of the planets. The Sun in the center of the solar system and the planets all orbiting in perfectly circular orbits. The right-hand figure above is familiar and indeed an image from *Revolutionibus.* In it, he criticizes the Ptolemaic system as a Frankenstein monster of sorts:
> “...the true symmetry of its parts...they have been like someone attempting a portrait by assembling hands, feet, a head and other parts from different sources. These several bits may be well depicted, but they do not fit together to make up a single body. Bearing no genuine relationship to each other, these fragments, joined together, produce a monster rather than a man.” To him, there was no alternative than to order the planets according to the length of their years. “Thus we discover in this orderly arrangement the marvelous symmetry of the universe and a firm harmonious connection between the motion and the size of the spheres….”
Finally, the Sun, rather than just another orbiting bit takes on a central role:
> “Behold, in the middle of the universe resides the Sun. For who, in this most beautiful Temple, would set this lamp in another or a better place, whence to illumine all things at once? For aptly indeed do some call him the lantern -- and others the visible god, and Sophocles’ Electra, the Watcher of all things. Truly indeed does the Sun, as if seated upon a royal throne, govern his family of planets as they circle about him.”
Circles. Always circles.
> **Wait.** We all learned that the orbits of the planets are not perfect circles, but the orbits are elliptical in shape. How did Copernicus get away with circles?
> **Glad you asked.** He couldn’t! In fact, he required the use of epicyles as well as Ptolemy. His were not around deferents that went around the Earth, but rather the Sun. But clearly, he could not make circles work by themselves.
```{admonition} Pens out!
:class: warning
But Copernicus needed help with his circles and that came in the form of as many epicycles as Ptolemy!
Was Copernicus afraid of the Church? Not really. Remember, he had supporters and he was respected in the Vatican. He dedicated *Revolutionibus* to Pope Paul III! Things got bad for Copernicus' work long after he had left the scene...and after the Vatican home-office decided to reboot and reassert its dominance in opposition to Protestantism and the general corruption of its far-flung clerical satellite offices.
The planets of our solar system orbit the sun.
```{admonition} Please answer Question 5 for points: :class: danger Copernican system accuracy ``` You might benefit from 6.1_cosmology2_copernicus_v1_.mp4 review and wrap-up of these sections.