The last two or three billion years of the histories of the small inner planets (like the Moon and Mercury) are dominated by contraction, whereas the late histories of the small icy satellites of Saturn and Uranus are dominated by expansion like that evidenced on Uranus’ moon Ariel. Why?

This crater on the Moon is probably ________.  

Which of the following are major differences between Io and Europa, moons of Jupiter?

What is the currently favored theory for the origin of the Moon?

Large amounts of water (as gas or liquid) on Venus ________.

What is the sinuous feature that extends across this image of the surface of Venus?

Comets are thought to have originated in a different part of the solar nebula than asteroids because

What do these features imply about the geologic history of Titan?

Examine the following image Ganymede. What are the regularly spaced troughs?

This is a colored shaded relief map of part of Earth’s continents (in green and brown) and seafloor (in shades of blue). Which of the letters is for a convergent plate boundary?