•Basis for comparisons is Earth
 •Properties of Earth
 •Similarities and differences with Mars and Venus help us understand Earth
 better (e.g., life,
 greenhouse effect, etc.)
 •
 •Won’t
 spend class time on basic properties (size, gravity, orbital period, length of
 day, number of
 moons, etc.) but you should have some relative ideas about these (see “Data Files” in text).