Sections Review

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

This material (including images) is copyrighted!. See my copyright notice for fair use practices. Select the photographs to display the original source in another window.


albedo climate convection
coriolis effect cosmic rays differentiation
escape velocity exosphere greenhouse effect
hydrostatic equilibrium ideal gas law mesosphere
ozone pressure solar wind
stratosphere temperature thermosphere
troposphere weather  


  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.
  4. pressure = k × number density × temperature.

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. In what way does a magnetic field protect a planet's atmosphere? In what ways is it involved with atmosphere loss?
  9. Why don't we feel a downward force on our bodies from the miles of air above us or why don't our bodies implode from the air pressure?
  10. What are two ways to increase the pressure of a gas?
  11. If a gas is compressed, what is expected to happen to the temperature of the gas?
  12. Explain why the pressure in your automobile tires is slightly less when they are cold than right after a long drive.
  13. Why do hot air balloons float upward?
  14. Why must deeper layers of an atmosphere exert more pressure?
  15. How would the depth of an atmosphere change if a planet warms up or cools off?
  16. What are three ways to make a planet's average temperature greater?
  17. 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.
  18. What would be the expected average surface temperature of Venus, Earth, and Mars if they did not have an atmosphere? Why are their actual average surface temperatures greater than the no-atmosphere temperature?
  19. If the clouds of Venus were perfect reflectors of visible light from the Sun so that no visible light reached Venus' surface, what would happen to the surface temperature? Explain your answer.
  20. If the atmosphere of Venus trapped all of the infrared light from the surface, what would happen to the surface temperature? Explain your answer.
  21. What are the primary greenhouse gases in the Earth's atmosphere? Which ones can remain in the atmosphere for decades or more?
  22. What are the layers of the Earth's atmosphere? What layers are not found on Mars and Venus and why is that?
  23. In what layer of an atmosphere do clouds form?
  24. Why does the temperature in our stratosphere increase with altitude and how is it beneficial to life on the surface?
  25. What heats the thermosphere of a planet?
  26. How are the three clouds on Jupiter and Saturn formed and what are they made of?
  27. Is there expected to be any water vapor at the same elevation as the ammonia clouds on Jupiter and Saturn? Why or why not?
  28. Is there expected to be any ammonia vapor at the same elevation as the water clouds on Jupiter and Saturn? Why or why not?
  29. Why are the cloud decks of Saturn found at greater depths than on Jupiter?
  30. Why is there so much convective motion in many planet atmospheres and some planet interiors?
  31. Why do low-pressure storms develop cyclonic spirals, and why are the patterns in the two hemispheres mirror images of each other?
  32. 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?
  33. 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.
  34. How do clouds affect the surface temperature of a planet?
  35. On Earth a molecule of water leaves the ocean. Describe the possible paths the molecule could take to return to the ocean.
  36. How do mountains affect a location's climate, particularly its annual amount of precipitation?
  37. How do ocean current affect a location's climate?
  38. How do the ocean currents affect air circulation and how do the winds affect ocean currents?
  39. What is the difference between weather and climate?
  40. If we cannot accurately predict the weather two weeks from now, how can we possibly predict the climate 50 years from now?
  41. How has the temperature of the Earth changed over the past million or so years and how do we know?
  42. What five things can cause long-term climate changes?
  43. How has the Sun's brightness changed since it formed?
  44. If water vapor is the dominant greenhouse gas on Earth, why is there such a concern about other greenhouse gases such as carbon dioxide or methane?
  45. What is a "positive feedback"? What is a "negative feedback"?
  46. What is responsible for triggering the ice ages on Earth?
  47. Is it possible for a planet's rotation axis and orbit shape to change? What affect would those changes have on a planet's average global temperature?
  48. In what ways are the atmospheres of the terrestrial planets like each other? In what ways are they different from each other?
  49. How are the atmospheres of Jupiter and Saturn different than the atmospheres of Uranus and Neptune?
  50. What are visible clouds of the jovian planets made of and why are they different from each other?

previousGo back to previous section -- next Go to next section

Go to Astronomy Notes home

last updated: June 2, 2010

Is this page a copy of Strobel's Astronomy Notes?

Author of original content: Nick Strobel