1. Announcements Turn in Homework 3, pick up Homework 4. Test this week: Wednesday or Thursday (your choice); SL 228 testing center; one hour time limit; no calculators; covers through today’s lecture, homework 1-3. I strongly recommend Sky View Café as a study aid!

2. Galileo and his Telescope 18 September 2006

3. Today: How Galileo, using the newly invented telescope, discovered startling facts about the sun, moon, stars, and planets

4. Galileo Galilei Italian scientist, 1564 - 1642 Made one of the first telescopes, and pointed it at the heavens...

5. Siderius Nuncius (The Starry Messenger) Venice, 1610 (Written in Italian, not Latin!)

6. Lunar topography... Sunspots...

7. Many new stars...

8. New “planets” orbiting Jupiter... At least some planets don’t orbit the earth; and earth isn’t the only planet with a “moon”!

9. Phases of Venus... Venus, at least, must orbit the sun, not the earth.

10. What happened to Galileo? He became famous (not just among astronomers) He started advocating Copernicanism (and ridiculing those who disagreed) Condemned by the Church, placed under house arrest

11. A final thought... Copernicus was Polish, Tycho Danish, Kepler German, Galileo Italian, Newton English. So what? Science belongs to everyone.