The Moon

    Our Moon is unique in the solar system in that it is so large compared to the planet that it orbits. It is heavily cratered and has large, flat maria which are found primarily on the Nearside. The Farside of the Moon contains virtually no maria. Since the highland regions of the Moon are virtually unchanged from its formation, we can see the record of over four billion years of cratering. Most of the impact craters on the Moon were formed in the first billion years of its history. Here is a simulation of the rate of cratering in the solar system.

    The Moon has nothing to speak of in the way of atmosphere, it appears to be geologically inactive. We also now suspect that the Moon, unlike the other natural satellites, was formed after a catastrophic collision with the early Earth. The process of formation may have looked like this. What evidence is there of this collision?

    Rilles, rays and regolith

    Rilles are trenches or valleys on the Moon. There seem to be two possible explanations for the origin of rilles. They may be collapsed lava tubes, or they may be the result of the cooling and shrinking of the thin crust of the Moon. Apollo 15 astronauts Irwin and Scott landed right next to a rather impressive rille on the Moon called Hadley Rille.

    Here is a good image of the ray system surrounding Tycho.

    The Moon is the only other body in the solar system that human beings have visited, thus far. In the late 1960's and early 70's, a total of twelve men walked on the surface as part of the Apollo program. The first landing, on Apollo 11, was made in the relatively flat region known as Mare Tranquilitatis. Hundreds of images of the surface were brought back to Earth, and the American flag was planted on the surface. Some have claimed that the landings were faked, but that has been sufficiently busted. Of course we all know that the landings were faked, as can be clearly seen in this classified video.

    NASA now has plans to go back to the Moon.

    What was it like to take a trip to the Moon? Apollo 17 astronaut Harrison Schmidt tells the story.

  This site is the best source of images of Lunar surface features. We will use this site in our lab exercise.

   Here is a highly detailed, animated map, which names some of the more important features on the Nearside of the Moon.

   My students need to be able to recognize the features listed here. Here is a map of the major maria.

Here is a good Lunar Atlas to help you.

Here are some of the essential facts about the Moon:

Radius 1738 km which is about one fourth the size of Earth

Rotation 27.3 days sidereal

Revolution 27.3 days , synchronous.

Atmosphere essentially none.

Surface Features Imbrium and the other maria
Highlands which are heavily cratered
Thousands of craters which are a few tens of kilometers in diameter. New impacts are occuring all of the time. Watch this video of a lunar impact. What about the formation of the crater named Bruno?

Moons or rings To the best of our knowledge, there are no natural small bodies orbiting the Moon.

Space Probes The Moon has been visited dozens of times by spacecraft, both manned and unmanned. Most recently, the Lunar Prospector mission has revealed evidence which points to the possibility of ice in the craters of the polar regions. The Chinese have made progress recently to land Humans on the Moon.

Are there other moons orbiting the Earth?

    Try this site for more information on the Moon!

   Myths and legends about the Moon are found in all cultures. Everyone's heard about the Man in the Moon but have you ever seen the "Woman in the Moon"?

   If you are interested, here is where you can buy a few acres of property on the Moon.

    Here is the lab on lunar surface features.

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Updated October 10, 2010