Chapter 9: Cratered Worlds (= Moon and Mercury)2. What is thesurface gravityon the Moon, compared to that at the Earth's surface?3. Does the Moon have more or less of a stock ofvolatilesthan the Earth does?YesWhatare`volatiles'?4. The section on "Exploration of the Moon" describes the missions to the Moon, including the Apollo program ofthe 1960s and 1970s. Here are some facts to know about Apollo:●How many Apollo missions went to the vicinity of the Moon?●How many people walked on the lunar surface?●What year was the first Apollo landing?●What year was the last Apollo landing?●Which mission had a geologist as a crew member?Let's compare the Moon to the Earth: What is a major part of the Earth's interior that is essentially mission from theMoon's interior? Carefully note the sentence that begins "It is as if the Moon were composed of…". What two thingsappear almost to have been "selectively removed" ?What's been found inside some craters near the Moon's poles?Here's an important thing to know about the Moon, which I emphasized in a lecture video: What are the differencesbetween themariaand thehighlands? Here are the specifics to know:●Which is smoother, which one is rougher?●Which is high-standing, which type is located at lower elevations?●What type of rock makes up each type of surface?●Which one is light-colored, which one is dark-colored?●Which surface is younger, which surface is older? (Hint: This comes from the basic principle of`dating planetary surfaces' that we learned in Chapter 7.)What is the relationship between maria andimpact basins? (Fig. 9.11 shows an impact basin that's about 1000km indiameter.)How long does a day last on the Moon, and how long does a night last?In a lecture video, I listed a third type of rock that's common on the Moon. What's it called, and how does it form?11. Make sure you understand how thecratering processworks. This is shown in Fig. 9.14, and described in theparagraphs before and after this figure.12. Why are nearly all lunar cratersround? What isejecta, and what arecrater rays?The section on "Using Crater Counts", and Fig. 9.19, talk about something called the "heavy bombardment". Thishappenedearlierthan how long ago?Make sure you're clear on theGiant Impact Hypothesis. How might such an event have worked, to form theMoon? What is the evidence for this event?
:What's so different about Mercury, compared to the other terrestrial planetary bodies? (See Fig. 9.20)How did astronomers figure out that Mercurydoesn'trotate in the same amount of time that it takes to orbit the Sun?In class, you probably copied down a diagram showing the "3:2 spin-orbit resonance" of Mercury. Even though youwon't have to re-draw this diagram on the test, it would be really helpful for your knowledge of Mercury if youcould. How long (e.g. in Mercury years) would a person on Mercury have to wait, if they wanted to experience oneday?