Homework 4: Due Sept 26, 2007

1. Read Mystery 8: What does the Universe Look Like?
2. Astronomers are currently testing Einstein's theory of gravity by bouncing lasers off of the Moon (no kidding---they are using special reflective panels left there by the Apollo astronauts!). What they are really after is the distance to the Moon, accurate to centimeters! What direct measurement will they make to figure this out?
3. Suppose star A has a parallax angle of 0.3", and star B has a parallax angle of 0.7". Which of these is farther away?
4. Suppose astronomers announce the discovery of a new planet around a star 45 light years away. What is the method they most likely used to find the distance to this star?
5. Why do objects have colors?