In class we quickly described some material that is scattered in the text in various ways. These are data that you could use for your "Origin of the Moon" Assignment.
 | The Moon is small. It's diameter is only about one-fourth that of Earth, and its mass is only about one-one-hundredth that of Earth. | |
| Materials on the Moon are the same materials that you would find on Earth. However, you find these in different proportions. On the Earth (as well as on Mars and Venus), you find more volatile matter than on the Moon. ("Volatile" matter, as described in Ch. 6, consist of elements that are more likely to vaporize than other matter ("refractory" matter). | |
| The Moon has "moonquakes", but they are weak, infrequent, and seem to come from very deep within the planet (compared to earthquakes). | |
| The Moon has no large scale magnetic force (like the one on Earth that would cause a compass to point north), although there is some magnetism in some rocks that suggests that the Moon did have a large scale magnetic force sometime in its history. | |
| The Moon has craters and maria. Craters, of course, suggest that lots of stuff (picture the formation of the solar system) smashes into larger bodies and leaves big potholes. The same kind of battering should have happened to Earth. This begs the questions: Why should the Moon have craters, but not Earth? How did Earth get rid of its potholes? | |
| The Moon has what's known as a 1:1 Spin-Orbit Coupling. This is the mechanism for why the Moon always shows us the same side at all times. As we'll see in Ch. 9, this is a perfectly natural phenomenon, but one that would take a lot of time to occur. | |
| If one tries to date the age of materials on Earth and on the Moon, we find that they seem to be equally old. | |
| We should also point out that Earth is the only Terrestrial that has a decent sized moon. Mercury and Venus have no natural satellite, and Mars has two dinky/asteroid satellites. This makes our Moon seem like something that is not an especially common thing. | |
| After a thorough read of Ch. 5, and a skimming glance of Ch. 6 (pausing occasionally to get a few more details on the items above), you probably have some other evidence at your disposal. Ch. 6 also provides one most likely explanation for where the Moon came from, but it should still be up to you to provide good evidence for this explanation (or some other explanation). |