From what you have learned in completing objectives 8 - 10, you should be able to compare and contrast the atmospheres of the four terrestrial planets. Be able to describe the properties of and the factors contributing to the evolution of the atmospheres of Mercury, Venus, Earth and Mars. You should consider the atmopsheres of the four terrestrials in terms of the following questions:

1. Does the planet have an atmosphere? Why? Why not?

2. What is the composition of the planet's atmosphere?

3. How did the planet's atmosphere evolve?

4. Can the atmosphere support life? Why? Why not?

5. Is the atmosphere similar or different from that of the Earth? In what way is it similar or different?

6. In what way is the evolutionary history of a planet's atmosphere similar or different from that of the Earth?

Complete These Self-check Questions: These questions and their answers are designed to help you determine how well you understand this objective and to provide additional instruction.

• There are none for this objective.

Homework Questions: Answer these homework questions after reading the on-line lecture and the readings in the text. Complete the self-check questions before attempting the homework. Follow the instructions for submitting the homework on this unit homework page.

• There are no homework questions for this objective. See the posted discussion questions for this unit.

• Terrestrial Atmospheres: The atmospheres of the terrestrial planets have some unique properties. Unlike the Jovian planets that have primary atmospheres that are composed of primordial hydrogen and helium, the atmospheres of the terrestrials have evolved to varying degrees. Mercury has no atmosphere. Venus and Mars have secondary atmospheres and the Earth has a tertiary atmosphere. Describe a fproperty of one of the terrestrial planet's atmosphere and the factors which have influenced its evolution.