CEN 511: Recent Discoveries in Astronomy

1. Venus has a retrograde spin. What does this mean, and what are some explanations for it?
2. Explain why the amount of solar energy absorbed within Venus' atmosphere and on its ground is practically the same as for the Earth, in spite of the fact that Venus is 30% closer to the Sun. How much more solar energy per square centimeter does Venus receive at the top of its atmosphere compared to at the top of the Earth's atmosphere (i.e., if you placed solar cells in close orbit around Venus and the Earth, what would be the ratio of power produced by the Venus cell compared to the Earth cell?).
3. What evidence exists that water was abundant on Venus early in its history?
4. If you poured water into a cup on Mars, what would happen to it? Would it remain in the cup for a long time, would it boil and evaporate, or would it freeze?
5. Summarize the "new" (i.e., 2003/2004) evidence indicating water was abundant on Mars in its early history.
6. The Earth has enough water to cover it to a depth of about a mile if the Earth's surface lacked valleys and mountains. How large a depth would the same amount of water have if all of it was transported to Mars?