Unit Two: Investigating the Sun-Earth-Moon System
2. Exploring the Moon
The moon is not just a small circle of light that moves across the sky and changes its pattern of light and dark each month. It is a world like the Earth on which you live; it is a place you can visit and walk on, pick up rocks, and look at the stars. The moon is a LOT harder to get to than places on Earth like New York City or Yellowstone National Park, and you need special clothing to go for a hike, but it is definitely a place to explore. People have looked at the moon from Earth for centuries, but a few have actually been there. With the advent of orbiting spacecraft and manned missions to the moon, a more complete picture of the moon can be formed.
First, get an overview of the side of the moon that always faces Earth. Go to the Astronomy Picture of the Day and download the image of the full moon at: http://antwrp.gsfc.nasa.gov/apod/ap990419.html. Display the image and examine it carefully. Make a short list of the different types of features you see: what's bright and what's dark; what's smooth and what's rough. This is the side of the moon that always faces Earth and has the familiar "man in the moon."
Now download an image of most of the moon's far side at: http://antwrp.gsfc.nasa.gov/apod/ap981008.html
Place both images side-by-side in your computer screen, full moon on the left and far side of the moon on the right. Note that the circular dark patch (Mare Crisium) and the cluster of small dark patches below it on the right side of the full moon image are visible on the left side of the far side image. Compare the two images: how are they the same, and how are they different? How well does you list of Near Side features work for far Side features?
Now look at a few features in greater detail. First consider craters on the Moon: how do craters of different sizes look? Visit the outstanding archive of lunar images at: http://www.lpi.usra.edu/resources/lunar_atlases/. Select the Lunar Orbiter Atlas of the Moon, and select Search by Feature Name. There are literally thousands of named craters on the Moon. For a sample of craters at different diameters, type in the following names, one at a time: Orientale, Schrodinger, Tsiolkovskiy, Theoplilus, Copernicus, Aristarchus, Timocharis, Bessel, Banting, Borel, Theophrastus. Select one of the Photo Numbers in the list that appears. On the photo number page, your crater will appear in the list at the bottom (with latitude, longitude, and size), and in the image, one with labels and one without. Click on the one with red labels (center) to identify your crater, and then on the one without labels (left) to get a clear view of it. Record the crater's, size, location, and description. Download the image for use later. (Sometimes you can find better images of individual features in the Apollo Image Atlas.) Try a search on a few of your crater names or locations in that archive to see what images are available there.
The list of craters above gives a reasonable sampling of craters of different sizes. Try a sampling of other craters of various sizes to see how they compare in appearance to the ones in the list.
- Use a software program to order your images according to crater size, scan back and forth through them until you become familiar with the changes you see as a function of size. Write a short description of the changes. Prepare a poster or PowerPoint showing the craters in order and include your written description.
The moon has other interesting features on its surface such as cliffs (called rupes), ridges (dorsa), and winding valleys (rima). A complete list is given at: http://planetarynames.wr.usgs.gov/ (click on Moon.) Images of the features can be found in the Orbiter Atlas by typing in the name of the feature type, like "rima." That will generate a list of similar features (try Rima Hadley.) Do a similar type of descriptive study and report for each of these features as you did for the craters. For features near Apollo landing sites, you might find some images of the features on the ground in the Apollo Image Atlas.