Announcements Exam 1 will be returned next time? For next time: Galileo and Rene Descartes (i.e. finish Chapter 5) Don’t forget the 1 st Project presentations are one week from Wednesday

Johannes Kepler 1571 – 1630

Born in Weil der Stadt Germany His grandfather had been the Lord Mayor but by the time Johannes is born the family had fallen on hard times. His father is a mercenary who comes and goes frequently and eventually goes for good when Johannes is 5

He was able to attend school Because grandfather was the mayor of Wiel der Stadt he was able to attend school at Maulbronn seminary

He studied at the University of Tubingen

As a teacher in Graz he wrote Cosmographic Mysteries

After receiving a copy of Cosmographic Mysteries, Tycho invited Kepler to Hven

Kepler doesn’t go to Hven but he does go to Prague after Tycho leaves Hven Tycho had established himself at Benatky Palace near Prague. Kepler visited for three months on leave from his school in Graz. Negotiations for a permanent position fail and he returns to Graz

Eventually, Kepler permanently leaves Graz for Prague

Kepler’s duties did not include observations, just calculations He calculated the locations of conjunctions of Jupiter and Saturn with a geometrical model.

At Tycho’s death, Kepler is appointed his successor Kepler explains his astronomy to Rudolph II

Tycho’s family wanted to keep possession of all the data so Kepler stole it Eventually ownership is sorted out and he credits Tycho in the Rudolphine Tables

Kepler’s 2 nd Law was actually his first Although he didn’t have the details worked out, he knew that planets travel fastest when closest to the Sun and slowest when farthest away before he knew the shape of the orbit.

Eventually he comes up with his 1 st Law of Planetary motion He publishes his first two laws in 1609

His 3 rd Law took another 10 years to develop Harmony of the Worlds is first published in 1619

His last publication is the Rudolphine Tables in 1627

As seemed fitting for his troubled life, his grave was destroyed within a few years of his death This is the house he lived in briefly in Regensburg. He had returned to try and collect on an old debt when he took ill and died. He was buried in the cemetery of the local protestant church