Question 9.7

If a giant impact such as the one that formed the Moon had occurred after life had arisen on Earth, what would have been the consequences?

Question 9.8

If you were an astronaut landing on an unexplored planet, how would you decide whether the planet was differentiated and whether it was tectonically active?

Question 9.9

Knowing how the Moon formed, what might you expect as a result if you were told that a large meteorite had collided with a planet twice its size? What could be the effect of this collision on the interior composition of this planet? How would the result of the impact differ if the meteorite were significantly smaller than the planet?

Question 9.10

During a dust storm on Mars, sediments fill the atmosphere with dust. But Mars has an atmosphere much thinner than Earth’s. To move sand, would the wind have to blow faster on Mars to compensate for this difference?

Question 9.11

Many scientists think that water is present on Mars. Today it is frozen, but 4 billion years ago, it may have been liquid. What happened? Describe all the possible mechanisms for this change. What evidence would you search for to help decide among these possibilities?

Question 9.12

How does the discovery of planets orbiting other stars contribute to the debate about the possibility of life elsewhere in the cosmos? What are the scientific and philosophical implications of the existence of life on the planets of other stars?

Question 9.13

What might be the advantages and disadvantages of living on a differentiated planet? On a tectonically active planet?