Astronomy 4

Reading Overview for Exam 3

Key Terms

Chapter: "Earth: the Active Planet" or "Earth: the Standard of Comparative Planetology"

comparative planetology

seismic waves



plate tectonics

midocean rise


primeval atmosphere

secondary atmosphere

ozone layer

greenhouse effect

Chapter: "The Moon and Mercury" or "The Moon and Mercury: Comparing Airless Worlds"



relative age

absolute age




Four hypotheses of Moon's origin:




Chapter 22: "Venus and Mars" or "Comparative Planetology of Venus and Mars"

subsolar point

composite volcano

shield volcano

coronae (on Venus)

outflow channel

valley network

NOTE: There will be no short-answer question on exam 3. The following questions may provide the basis for some multiple-choice questions, however.

Review Questions

Why would you include the moon in a list of the terrestrial planets?
What characteristics must Earth's core have in order to generate a magnetic field?
What evidence can you cite that the Atlantic Ocean is growing wider?

The Moon and Mercury
How could you find the relative ages of the moon's maria and highlands?
How can you tell that Copernicus is a young crater?
How does the large-impact hypothesis explain the moon's lack of iron?  Of volatiles?
What evidence can you cite that Mercury has a partially molten, metallic core?

Venus and Mars
Why might you expect Venus and Earth to be similar?
What evidence shows that Venus has been resurfaced within the last billion years?
Why doesn't Mars have mountain ranges like those on Earth?  Why doesn't Earth have large volcanoes like those on Mars?
Propose an explanation for the nearly pure carbon dioxide atmospheres of Venus and Mars.  How did Earth avoid such a fate?
How can planetary scientists estimate the ages of the outflow channels and valley networks on Mars?