Announcements Exam 1 is next time. It will cover Chapters 1 – 5. Sample questions are posted. The exam will consist of 15 multiple choice questions and 3 essay questions. Open book so be sure to bring yours. Don’t forget the 1 st Project presentations are two weeks from Thursday. A written paper and oral presentation is required

Rene Descartes 1596 – 1650 I think, therefore, I am Not an astronomer but a philosopher/mathematician. Like Plato, though, his philosophy influences astronomical thought.

Born in La Haye near Tours in southern France His father was a Councilor in Parliament and an intellectual so he was raised an environment conducive to learning and education

He studied at the Jesuit College in La Fleche and then Canon Law at Poitiers 17 th Century painting of the Jesuit College at La Fleche The modern day University of Poitiers

In 1628 he moved to Holland where he stayed until 1649, moving frequently Dordrecht (1628), Franeker (1629), Amsterdam ( ), Leiden (1630), Amsterdam (1630-2), Deventer (1632-4), Amsterdam (1634-5), Utrecht (1635-6), Leiden (1636), Egmond (1636-8), Santpoort ( ), Leiden (1640-1), Endegeest (a castle near Oegstgeest) (1641-3), and finally for an extended time in Egmond-Binnen (1643-9).

Most of his major works were published while he was in Holland Discourse on The Methods was first published in 1637

His Principles of Philosophy was published in 1644

The universe of Descartes was filled with an aether Matter filled the universe. It was only through motion that “objects” had form

His work was of sufficient importance to geometry that we call the coordinate system Cartesian

In 1649 he is invited to Stockholm by Queen Christina

He dies in Stockholm on February 11, 1650 His tomb is at the Church of Saint Germain des Pres, Paris

The stage is now set for the rise of Newtonianism

William Gilbert proposed the Earth was a huge magnet Published in 1600, On The Magnetic was a treatise on magnetism

English intellectuals of the early 1600’s gathered at Gresham College Check out the Gresham College website

In 1660 the Greshamites form the Royal Society The Philosophical Transactions of the Royal Society have been published since 1665 and are available online

Robert Hooke is the Curator of Experiments for the Royal Society Known as London’s Leonardo because of his involvement in the rebuilding of London after the great fire of His experiments on the pendulum gave rise to Hooke’s Law. Check out the official Robert Hooke website

Hooke attempted to prove that Earth moved An Attempt to Prove the Motion of the Earth by Observations Made by: Robert Hooke Fellow of the Royal Society. *Senec. Nat. Qu. lib. I. cap. 30. `Nè miremur tam tardè erui quæ tam altè jacent. Wether the Earth move or stand still hath been a Problem, that since Copernicus revived it, hath much exercised the Wits our best modern Astronomers and Philosophers, amongst which notwithstanding there hath not been any one who hath found out a certain manifestation either of the one or the other Doctrine. The more knowing and judicious have for many plausible reasons adhered to the Copernican Hypothesis: But the generality of others, either out of ignorance or prejudice, have rejected it as a most extravagant opinion. A major result of this work was the idea of mutual attraction

Hooke postulates an attractive force between the Sun and planets that diminishes with distance He never showed it was an inverse square law, just an inverse law of some sort.

In a series of letters, Hooke spurred Newton into thinking about Gravity Hooke’s “discussions” with Newton became somewhat critical of Newton’s ideas. As a result, Newton despised Hooke and eventually tries to erase all traces of him from the Royal Society records