1. 1B Timeline Copernicus 1473-1543 Tycho 1546-1601 Kepler 1571-1630 Galileo 1564-1642 Newton 1642-1727

2. 1B Geocentric (Ptolemaic) System The accepted model for 1400 years The earth is at the center The Sun, stars, and planets revolve around the earth: explains daily movement

3. 1B Heliocentric (Copernican) System Sun at center (heliocentric) Uniform, circular motion Moon orbited the earth, the earth orbited the sun as another planet

4. 1B Copernicus vs. the Church Copernicus was not trying to contradict church teachings. As a canon, he believed those teachings He did not wait to publish until he was near death because he was afraid. Rather, he thought the work incomplete. However, other people found a heliocentric universe to be in direct contradiction to statements in the Bible and argued against Copernicus and his system –Martin Luther in one of his "Table Talks" in 1539: People gave ear to an upstart astrologer who strove to show that the earth revolves, not the heavens or the firmament, the sun and the moon....This fool wishes to reverse the entire science of astronomy; but sacred scripture tells us [Joshua 10:13] that Joshua commanded the sun to stand still, and not the earth. –http://www.stcloudstate.edu/~physcrse/astr106/bible.htmlhttp://www.stcloudstate.edu/~physcrse/astr106/bible.html

5. 1B Galileo Turned a telescope toward the heavens Made observations that: –contradicted the perfection of the heavens Mountains, valleys, and craters on the Moon Imperfections on the Sun (sunspots) –Supported the heliocentric universe

6. 1B Tycho Brahe Believed the Sun and Moon revolved around the Earth and that the other planets revolved around the Sun. Triangular sextant Armillary Sphere

7. 1B The skies change Tycho observed 2 phenomena that showed the heavens DO change: –Noticed a new star in the constellation Cassiopeia –Noticed a Comet in the year 1577

8. 1B Johannes Kepler Kepler succeeded Tycho (Tycho’s assistant) He discovered that the earth and other planets orbit around the sun. Suspecting the sun had a force over the planets, he investigated magnetism It did lead him to the idea of elliptical orbits.

9. 1B A force for planetary motion Newton proposes a force which controls the motion of the planets – GRAVITY The larger the mass, the larger the force of gravity The further the distance, the smaller the force of gravity Newton’s law of gravity F =mg

10. 1B Gravity