Exam 7: Earth and the Terrestrial Worlds

Recent evidence suggests that Mars once had a global magnetic field. Assuming this is true, which of the following could explain why Mars today lacks a global magnetic field like that of Earth?

What type of stresses broke Earth's lithosphere into plates?

Why does the burning of fossil fuels increase the greenhouse effect on Earth?

Describe the three sources of internal heat of the terrestrial planets.

Which of the following planets has the least substantial atmosphere?

Briefly explain why Mercury, Venus, and the Moon do not have significant erosion. Relate erosional activity to planetary size and distance from the Sun.

If the polar ice decreases, what would happen, and why?

Which two geological processes appear to have been most important in shaping the present surface of Venus?

Which two factors are critical to the existence of the carbon dioxide (CO₂) cycle on Earth?

Which of the following has virtually no effect on the internal structure of a planet?

If the Earth were to warm up a bit, what would happen?

Suppose Earth's atmosphere had no greenhouse gases. Then Earth's average surface temperature would be

Which of the following worlds have the thinnest lithospheres?

What makes us think that Mars must once have had an atmosphere that was warmer and had higher surface pressure?

What do we mean by a runaway greenhouse effect?

How deep is an impact crater compared to its width?

Why is Mars so much colder than the Earth?

The Gaia Hypothesis: The Gaia hypothesis, due to James Lovelock, maintains that the Earth-- its atmosphere, the oceans, the land, and life, represents a complex interacting system that will always seek to maintain a life-supporting environment. Discuss the operation of the Earth's carbon dioxide cycle and how it might relate to the Gaia hypothesis. The Gaia hypothesis is still quite controversial. Perform some research (either in your library or on reputable internet reference sites) and summarize in a few paragraphs the arguments for and against Gaia.

The choices below describe four hypothetical planets. Which one's surface would you expect to be most crowded with impact craters? (Assume the planets orbit a star just like the Sun and that they are all the same age as the planets in our solar system.)

Given the current emission rate of carbon dioxide, how much will the average Earth's temperature increase in the next century?