Harvey's Circulation of Blood

Harvey’s Circulation of Blood

Before the seventeenth century, scientific concepts were mostly based on ancient philosophical and theological explanations (Lubitz SA.). By the early 17th century, with the invention of different kinds of new devices, experimental and observational methods had been used to turn most of the traditional theoretical concepts upside down.  
One of the most astonishing announcements was made by Johannes Kepler. He described planetary orbits as elliptically revolving around the Sun at one focus, which was in conflict to the wide-spread Platonic idea of circular motion. Kepler worked as Tycho Brahe’s assistant in order to assess the accuracy of Brahe’s data in his observations, which were collected over a period of some 25 years. However, Brahe kept his original data from Kepler. Until after Brahe died, Kepler immediately took the data from Brahe’s property in secret in order to perform calculations to establish his theories based on Brahe’s data (Steven C. Frautschi).
Kepler was assigned to establish the orbit of Mars. He was one of Copernicus’ proponents and originally believed in that planets were moving around the sun in perfect circular motion (Brian S. Baigrie). Brahe’s data allowed Kepler to determine twelve points on the orbit of Mars. However, these points didn’t perfectly fit into a circular motion for Mars (Steven C. Frautschi). Instead, Kepler made a model with elliptical orbit for Mars combining Brahe’s data and his mathematical method.   The data fitted quite well into the model (Steven C. Frautschi). Kepler was then forced to accept the fact that the planets were orbiting in an elliptical shape. From Kepler, in his astronomical book of “Astronomia Nova”: "I was almost driven to madness in considering and calculating the matter. I could not find out why the planet (Mars) would rather go on an elliptical orbit.... With reasoning derived from physical principles agreeing with experience, there is no figure left for the orbit...