1. Welcome to Modern Astronomy Fall 2007 Initial pleasantries, who I am, who you are This should be the most interesting course you take in college National Solar ObservatoryNational Solar Observatory

2. The Sun is more interesting some times (wait 5 years)

3. Example 1: The “Dark Matter”

4. Example 2: Arcturus (see it tonight) Distance: 37 light years

5. Arcturus (bright star overhead) as an immigrant from another galaxy The Milky Way (and other galaxies) catch and devour small galaxies

6. Details from the Syllabus

7. The Sky Tonight The Sun sets (7:48 PM) Arcturus and Spica in the west (stars) Antares (star) and Jupiter in the south Vega (star) and the Milky Way overhead The Andromeda Nebula in the east Constellation of Scorpius Constellations Internet LinkConstellations Internet Link

8. Tomorrow Morning: Total Eclipse of the Moon Timetable for lunar eclipse

9. An Overview of the Solar System

10. Size scales in the solar system Basic unit: 1 meter 1 kilometer = 1000 meters = 0.6214 miles Diameter of Earth: 12756 kilometers (~ LA to Sydney) Closest object in space: Moon, 384,000 km average distance Most prominent object is astronomy: Sun, 149.6 million kilometers; 1 Astronomical Unit demo

11. The Sun

12. Facts about the Sun Distance: 149.6 million kilometers = 1.496E+11 meters = 1 astronomical unit Radius = 695,990 kilometers = 6.960E+08 meters (109 times radius of Earth) If Earth were scaled to 1 foot globe size, the Sun would extend from goal line to 30 yard line at Kinnick stadium The Sun, not the planets (including Earth) is the dominant object in the solar system