• Write your answers on a regular 8.5"x11" paper -
• PLEASE STAPLE TOGETHER.
• Don't forget your name!
• A single number or word on its own is not an answer. You must show HOW you came to your answer and give the units of quantities.

This homework relates to Sessions 12 as well as Chapter 9 of the textbook.

1. Which has the thinner mantle of ice? Explain why.
2. Which is expected to have greater radioactivity heating the interior? Explain why.
3. Look at Figure 9.10 carefully. Which planetary formation properties (shown in green at the top - mass & radius, distance from Sun, composition, rotation rate) determine the internal temperature of a planet, and why?
4. Yrucrem has the same mean density (2.8 g/cm3) as Sram but Yrucrem has a radius half that of Sram. Which planet will have cooled faster? Explain.
5. What would be the evidence that you would look for on the surfaces of Sram and Yrucrem to confirm your hypothesis of which planet had cooled first?

1. When a meteorite hits one of the terrestrial planets it makes a crater with a diameter of about 20 times the diameter of the inpactor (the book says ~10 times, ~20 times is perhaps more typical). "Guesstimate" (= nerdspeak for guess/estimate) the size of the impactors that made the large Mare on the Moon. (Hint: Figure 9.12 shows mare on the Moon - the radius of the Moon is 1740 km)
2. The craters in Fig 9.12a look like "seas". What material flooded these craters?
3. Compare the surfaces in Fig 9.23 and Fig. 9.27b. Which surface is older? Explain.
4. Look carefully at Fig 9.15. How does cratering feed back to modify the original (formation) properties of the planet?
5. HOW do we know that the rate of cratering on the Moon changed dramatically about 3.8-3.9 billion years ago? (Give a brief but clear explanation in about 3-5 sentences).
6. The surface of Mercury is often described as "saturated" with craters. Give a sentence describing what this means in your own words.

1. The viscosity of lava is an important factor in controlling the shape of volcanic features. Rank the volcanic features shown in the following pictures according to the viscosity of the lava that made them - rank from lowest to highest viscosity. (i) Fig 9.12 lunar mare, (ii) Fig 9.29c Venus domes, (ii) Fig 9.26d Olympus Mons.
2. Look carefully at Figure 9.18. How does the formation property composition affect volcanism?
3. What geological controlling factor (center row) controls the amount of volcanism?
4. Following from part (c) above, why would you expect a larger planet to have more volcanism?
5. How does volcanism relate to the other geological processes (bottom row)? (e.g. ways that volcanism makes or destroys geological features)

1. Find 3 figures in Chapter 9 which show tectonics. Describe what you see and why each is evidence of tectonics.
2. Look at Figure 9.20 carefully. Which geological controlling factor controls tectonics? How?
3. Following from part (b) above, why would you expect a larger planet to have more tectonics?
4. How is tectonics related to the other geological processes?

1. Start off with the planetary formation properties and Figure 9.10 - which of these are substantially different between Earth and Moon?
2. Would you have expected Earth and Moon to have received the same flux of bombarding impactors? Explain.
3. What has happened to the craters on the Earth? Relate you explanation to the geological controlling factors.
4. Look at Figure 9.20 carefully. Which geological controlling factor controls tectonics? How?