Homework 3: Due September 19, 2007

1. Why is it so hard to figure out how far away a particular star is?
2. On September 11, 2007, there was a total solar eclipse viewable from Indonesia. On August 28, 2007, there was a total lunar eclipse viewable from Ogden, UT. Is the timing of these two eclipses a coincidence, or is it a natural result of celestial phenomena? (Be sure to explain your answer for full credit!)
3. Suppose the Earth went around the Sun at twice its current rate. What would be the length of the sidereal day? What would be the length of the solar day?
4. The tilt of the Earth's axis causes the seasons. How?