Announcements Exam 1 will cover Chapters 1, 2, 3, 4 & 5. Sample questions have been posted. Format will be 15 MC’s (3 points each) and 3 essays (18 points each) from a list of 5. Open Book! For Tuesday read Chapter 5.

With the invention of the printing press in 1450, astronomy texts flourished Regiomontanus’ Epitome of the Almagest published in 1496 Sacrobosco’s Sphaera Mundi published in 1472 Peuerbach’s Theoricae Novae Planetarum first published in 1474

The scientific community of the late 1400’s and early 1500’s was ripe for challenging the ideas of the Greeks Aristotle’s explanation of projectile motion was both absurd and clearly wrong. If this was wrong, what of the rest of Aristotle’s Physics?

What everyone hated was Ptolemy’s Equant

Nicolaus Copernicus February 19, 1473 – May 24, 1543

Educated in Krakow, he studied astronomy from Sacrobosco’s text And mathematics from Euclid’s Elements He doesn’t receive a degree here, though

In 1495 his uncle arranges for him to become a Canon of the church in Frombork

He gets a leave of absence to study canon law in Bologna He also conducted astronomical observations with Domenico Maria de Novara at the Specola. He doesn’t receive a degree but returns to Frombork in 1501

He also studied medicine at the University of Padua He doesn’t finish, though. The program of study is three years and he is only granted two years leave from his position in Frombork

He finally receives a degree in Canon Law around 1504 After finishing, he goes to live with his uncle (the bishop of Warmia) and is the attending physician when he falls ill in 1507 and eventually returns to Frombork in 1510 The university that finally grants him a degree is the University of Ferrara which is near Venice

In 1515 he publishes his first writings on a heliocentric universe Commentariolus is an early outline of the heliocentric model. It is only a few pages long and doesn’t go into the mathematics

In 1539 In 1539 Georg Joachim Rheticus visits and convinces him to publish the full works Rheticus is a mathematician and brings several math books to show the quality of printing available in Germany

De Revolutionibus Orbium Coelestium First published in 1543

Andreas Osiander added a foreword to De Revolutionibus To the Reader Concerning the Hypotheses of this Work There have already been widespread reports about the novel hypotheses of this work, which declares that the earth moves whereas the sun is at rest in the center of the universe. Hence certain scholars, I have no doubt, are deeply offended and believe that the liberal arts, which were established long ago on a sound basis, should not be thrown into confusion. But if these men are willing to examine the matter closely, they will find that the author of this work has done nothing blameworthy. For it is the duty of an astronomer to compose the history of the celestial motions through careful and expert study. Then he must conceive and devise the causes of these motions or hypotheses about them. Since he cannot in any way attain to the true causes, he will adopt whatever suppositions enable the motions to be computed correctly from the principles of geometry for the future as well as for the past. The present author has performed both these duties excellently. For these hypotheses need not be true nor even probable. On the contrary, if they provide a calculus consistent with the observations, that alone is enough.…

Like Ptolemy’s Almagest, De Revolutionibus described how to calculate the positions of planets Watch Museo Galileo Copernican System video

The numbers weren’t much better than Ptolemy’s Origanus used Copernicus’ method to calculate the position of Mars (dashed line). Compare it to the calculation using Kepler’s laws

The Copernican revolution would change the way we view our place in the universe Conversation With God by Jan Matejko in 1872