The Outer Earth
1. What is Rayleigh scattering, and what are its most noticeable effects for us on Earth?
2. What is the greenhouse effect, and what is its importance to the surface temperature of the Earth?
3. What is convection, and how does it affect the Earth's atmosphere?
4. Explain how the Moon produces tides.
5. If the Moon had oceans like the Earth, what would the tidal effect be? How many high and low tides would there be each Moon-day? How would the height of tides on the Moon be related to those on the Earth?
6. If the Earth had no Moon, do you think we would know anything about tidal forces?
7. Is the greenhouse effect helpful or harmful for the Earth? Give examples. What would be the consequences of an enhanced greenhouse effect?
The Inner Earth
1. By comparison with its average density, what do the densities of water and the Earth's crust tell us about the interior?
2. Describe the Earth's magnetosphere, and describe how it was discovered.
3. How does the Earth's magnetosphere protect us from the harsh conditions in interplanetary space?
4. How do geologists use earthquakes to map the Earth's interior?
5. Compare and contrast P-waves and S-waves, and explain how they are useful in geology.
6. Give two reasons for thinking the Earth's core is liquid.
7. What does differentiation tell us about the Earth's history?
8. How does convection affect the interior of the Earth?
9. How does radioactivity allow us to estimate the age of the Earth?
10. How did radioactive decay heat the Earth early in its history, and when did this heating end?
11. What process is responsible for the large-scale features on the Earth's surface (mountains, oceanic trenches, and so forth)?
12. What conditions are needed for there to be a dynamo in the core of the Earth, and what does this dynamo produce?
13. How do we know that the Earth's magnetic field has reversed in the past, and what effect do you think these reversals may have had on life?
1. How is the distance to the Moon most accurately measured?
2. Employ the concept of escape speed to explain why the Moon has no atmosphere.
3. In was sense are the Lunar 'maria' seas?
4. What is a synchronous orbit, and how did the orbit of the Moon come to be this way?
5. What causes erosion on the Moon, and why is it slower than on Earth?
6. What is the evidence that there is ice on the Moon?
7. Unlike the Earth, the surface of the Moon undergoes extreme temperature changes. Why?
8. Describe a widely accepted theory of the Moon's origin.
9. From a position on the Moon from which the Earth is visible, would the position of the Earth change in the sky over the course of a month? What changes in the appearance of the Earth would occur?
10. What is a terminator line? What is the advantage of observing the terminator line on the surface of the Moon? If you were on a terminator line on the surface of the Earth, what time of day would it be?
11. Where on the Moon would be the best place to make astronomical observations? What would be the advantages of this over observing from the Earth?
12. How is the varying thickness of the Moon's crust related to the presence or absence of maria?
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.
The Planet Venus
1. Why does Venus appear so bright in the sky? On what does the brightness of a planet depend?
2. Why is Venus always near the Sun in the sky?
3. Why do astronomers think that the near resonance between Venus's rotation and orbit, as seen from Earth, is not really a resonance?
4. Describe one observational problem associated with Venus's near resonance of rotation and orbit.
5. What is our current best explanation of Venus's slow, retrograde rotation?
6. If you were standing on Venus, how would the Earth look?
7. How did radio observations of Venus in the 1950s change our understanding of the planet?
8. How do the continents of Venus differ from Earth's continents?
9. What is the evidence for active volcanoes on Venus?
10. Given that Venus like Earth has a partially melted iron core, why doesn't it have a magnetic field like Earth's?
The Atmosphere and Surface of Venus
1. What did ultraviolet images returned by Pioneer Venus show about the planet's high-level clouds?
2. Name three ways in which the atmosphere of Venus differs from that of Earth.
3. What are the main constituents of Venus's atmosphere? What are the clouds in the upper atmosphere made of?
4. What component of Venus's atmosphere causes the planet to be so hot? Explain why there is so much of this gas in the atmosphere of Venus compared with its presence in Earth's atmosphere. What happened to all the water that Venus must have had when the planet formed?
5. Earth and Venus are nearly alike in size and density. What caused one planet to evolve as an oasis for life, while the other became a dry and inhospitable world?
6. If Venus had formed at Earth's distance from the Sun, what do you imagine its climate would be like today? Why do you think so?
7. How do the impact craters on Venus differ from those on other bodies in the solar system?
8. What is the evidence that volcanism of various types has changed the surface of Venus?
9. Do you think there might be life on Venus? Explain your answer.
10. Do you think Earth is in any danger of a runaway greenhouse effect like that on Venus?
1. Why is opposition the best time to see Mars from Earth?
2. Why are some Martian oppositions better than others for viewing Mars?
3. How were the masses of Mars's moons measured, and what did these measurements tell us about their origin?
4. What are the Martian 'canals'?
5. What is the evidence that Mars never melted as extensively as did Earth?
6. How would Earth look from Mars?
7. Why is Mars red?
8. Why are Martian volcanoes so large?
9. Describe the major large-scale features on the surface of Mars.
10. Mars has a radius about ½ Earth's and a mass about 1/10 Earth's; what is its density relative to the Earth?
Atmosphere and Surface of Mars
1. Describe the atmospheric conditions in the Southern Hemisphere of Mars during the summer.
2. Describe the two Martian polar caps – seasonal and permanent composition, and the differences between them.
3. Why couldn't you breath on Mars?
4. What is the evidence that water once flowed on Mars?
5. Is there liquid water on Mars today? Justify your answer.
6. Is there water on Mars today in any form? Again, justify your answer.
7. What is the evidence that Mars once had an extensive ocean? Where was it?
8. If Mars were colonized, what resources could Mars provide and what would have to be brought from Earth?
9. Since the atmosphere of Mars is mainly the greenhouse gas carbon dioxide, why isn't there a significant greenhouse effect warming its surface?
10. Compare and contrast the evolution of the atmospheres of Mars, Venus, and Earth.