Mercury

1. Why is Mercury rarely seen with the naked eye?

2. Why did early astronomers think that Mercury was two separate planets?

3. Employ the concept of escape speed to explain why Mercury has no atmosphere.

4. Give two similarities and two differences between the surfaces of the Moon and Mercury.

5. What does it mean to say that Mercury is in a 3:2 spin-orbit resonance? Why didn't Mercury settle into a 1:1 spin-orbit resonance with the Sun like the Moon did with Earth?

6. What is a scarp? How are scarps thought to have formed? What is the basis for believing that the scarps on Mercury formed after most meteoritic bombardment had ended?

7. Unlike the Earth, the surface of Mercury undergoes extreme temperature changes. Why?

8. How is Mercury's evolutionary history similar to that of the Moon? How is it different?

9. Explain why Mercury is never seen overhead at midnight in Earth's sky.