Sections Review

Chapter index in this window —   — Chapter index in separate window

Vocabulary

Formulae

1. escape velocity = Sqrt[(2 × G × mass/distance)], where the mass is the mass of the planet or moon, the distance is measured from the center of the planet or moon, and G is the universal gravitational constant.
2. average gas speed = Sqrt[(3 × k × temperature/gas molecule mass)], where k is the universal Boltzmann constant.
3. general rule of atmophere escape: if the average gas molecule speed is less than 0.2×(the escape velocity), then more than 1/2 of that type of gas will remain after 1 billion years.

Review Questions

1. In what ways are jovian planets different from terrestrial planets?
2. Why are jovian and terrestrial planets different from one another?
3. What two things determine the thickness of a planet's atmosphere?
4. Which will have a large escape velocity: something with small surface gravity or something with large surface gravity?
5. Does a moon's escape velocity depend on the gravity of the planet it orbits? If yes, explain how; if not, why not?
6. At a given temperature, which molecule travels fastest: a massive one or a light one? Which of the two would most likely escape from a planet's atmosphere? Which of the two would most likely remain?
7. Which of the following things would tend to make a thick atmosphere: cold temperature, high gas particle mass, weak gravity, outgassing from the interior (volcanic eruptions)?
8. On a planet with a thin atmosphere, what would you expect for the temperature difference between night and day to be (small, moderate, large)? Explain why.
9. Why is there so much convective motion in many planet atmospheres and some planet interiors?
10. Why do low-pressure storms develop cyclonic spirals, and why are the patterns in the two hemispheres mirror images of each other?
11. Suppose the atmosphere circulation on the Earth were stopped. What would be the effect on the temperature of the atmosphere near the equator, at the mid-latitudes, and near the poles?
12. If the Earth rotated faster, would the coriolis effect be greater or less than what it is now? Explain your answer by comparing what would happen to a rock thrown from the north pole and landing on the equator on a rapidly spinning Earth with that thrown on a slowly spinning Earth.

Go back to previous section -- Go to next section

Go to Astronomy Notes home

last updated: June 2, 2007