2. . Mr. K. NASA/GRC/LTP Edited: Ruth Petersen Part 2 The Planet

3. Preliminary Activities 1. Use your science book,an encyclopedia, or the Internet to explore the phases of the moon. Assume that the moon is a sphere. Explain the phases. 2. How would the appearance of the phases change if the moon had a bulge on one side? Try using a golf ball or a tennis ball, a bright light source, and some modeling clay to help you visualize.

4. 3. Why do you think that the planets and their moons are spherical and not some other shape? ( Hint: Assume that they were initially molten. What can you say about gravitational potential energy? Use a physics text if necessary. ) How do you think a planet might get “out of round”? 4. Use your science book, an encyclopedia, or the Internet to list the various cloud types seen on Earth (including fogs!). What does the presence of a certain type of cloud tell you about the weather?

5. 5. Use a map or an atlas to draw the shape of a major river, such as the Amazon. Become familiar with and describe the various features. 6. Why is water important? 7. What other features of Earth as a planet do you think are important? ( e.g., What makes your compass work?) 8. Use a dictionary to write a definition for the phrase “comparative planetology.”

6. Mars

7. Earth Mars MoonPhobos & Diemos COMPARATIVE SIZES Sun

8. More Data on Mars

9. Tarsus

10. A Day to Remember!

11. Mars Tarsus & Mariner’s Valley Tarsus Olympus Mons Mariner’s Valley

13. Olympus Mons

14. Scale Drawing showing Relative Sizes of Mt. Everest and Olympus Mons

15. Was Mars ever warmer and wetter? ?

16. Dry River Beds Alluvial Fan Ghost Crater

17. Morning Clouds in Mariner’s Valley

18. Did Mars ever have a magnetic field? Possibly. Data is still being analyzed. N S

19. Magnetic fields trap charged particles from space. Warmth, water, and a good radiation shield are essential for life.

20. Any Questions, Earthlings?

21. Follow-Up Activities 1. Make a list of planetary characteristics for Mars and the Earth. Find similarities and differences. 2. Use an encyclopedia or the Internet to obtain information on the Hawaiian volcanoes. The Martian volcanoes are similar. How is this significant to a Mars planetologist? 3. Why do you suppose that the Martian volcanoes are so much larger than those on Earth?

22. 4. Has the Earth ever been struck by a large meteorite as Mars may have been? 5. What evidence would you look for on Earth to answer this question? 6. If there is liquid water on Mars today, it would have to reside somewhere warm. Can you suggest any place on Mars we might find a region warm enough for liquid water? Use your imagination - think outside of the box!

23. Web Sites for Further Exploration http://www.grc.nasa.gov/WWW/PAO/html/ marspath.htm http://marsnt3.jpl.nasa.gov http://antwrp.gsfc.nasa.gov/ http://nssdc.gsfc.nasa.gov/ http://mars.sdsc.edu/mgs/index.html

24. joseph.c.kolecki@grc.nasa.gov