List several ways that Venus, Earth, and Mars are similar, and several ways they are different.
Compare the current atmospheres of Earth, Venus, and Mars in terms of composition, thickness (and pressure at the surface), and the greenhouse effect.
How might Venus’ atmosphere have evolved to its present state through a runaway greenhouse effect?
Describe the current atmosphere on Mars. What evidence suggests that it must have been different in the past?
Explain the runaway refrigerator effect and the role it may have played in the evolution of Mars.
What evidence do we have that there was running (liquid) water on Mars in the past? What evidence is there for water coming out of the ground even today?
What evidence is there that Venus was volcanically active about 300–600 million years ago?
Why is Mars red?
What is the composition of clouds on Mars?
What is the composition of the polar caps on Mars?
Describe two anomalous features of the rotation of Venus and what might account for them.
How was the Mars Odyssey spacecraft able to detect water on Mars without landing on it?