Question 1

Suppose Mars had turned out to be significantly smaller than its current size, say about the size of our Moon. How would this have affected the number of geological features due to each of the four major geological processes?

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Question 2

Evidence for Life: Imagine that recent advances in technology have allowed the discovery of several very low mass (much less than the mass of Jupiter) planets around nearby, Sun-like stars. Assume all that is known about these planets is their mass, their size, and the characteristics of their orbits (ie semi-major axis and eccentricity). You are asked to speculate on whether or not life (similar to that on Earth) might exist on these planets. How would you answer this question? You are then asked what new observations we might make to help settle this question. How would you respond?

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Question 3

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

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Question 4

The process in which one plate slides under another is called subduction and occurs where seafloor crust descends into the mantle below continental crust.

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This is a correct statement. Subduction occurs at convergent plate boundaries where one plate is denser than the other and sinks beneath it. This process is responsible for forming deep ocean trenches and volcanic arcs.

Question 5

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.

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Question 6

What is the main visual difference between the lunar maria and the rest of the lunar surface? What are the implications of this observation?

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Question 7

Why do we think Mercury contracted after it formed?

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Question 8

Why did Earth retain most of its water while Venus and Mars lost theirs?

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Question 9

Explain how we can estimate the geological age of a planetary surface from its number of impact craters.

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Question 10

What is a magnetosphere and how are magnetospheres related to planetary atmospheres?

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Question 11

Briefly describe how the greenhouse effect makes a planetary surface warmer than it would be otherwise.

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Question 12

Earth outgassed as much carbon dioxide as Venus, but it is locked up in the oceans and rocks.

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This statement is true. Early in their histories, both Earth and Venus outgassed large amounts of carbon dioxide, but the Earth's oceans and rocks have absorbed and stored much of it over time. This is why Earth's atmosphere has a much lower concentration of carbon dioxide compared to Venus, which has a thick, carbon dioxide-rich atmosphere.

Question 13

Earth and Venus both presumably had similar gases outgassed from their volcanoes. Briefly explain how their atmospheres ended up so different.

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Question 14

Briefly describe how the solar wind affects magnetospheres and how auroras are produced.

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Question 15

Public Policy Informed by Science: Research the Montreal Protocol (1987) that led to a world-wide ban in the use of chlorofluorocarbon compounds (CFCs). What was the scientific case for the ban? Why do you think such coordinated, world-wide action was possible in this case, yet a global consensus has not emerged on how to respond to the challenge of climate change?

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Question 16

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

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Question 17

Earth is the only terrestrial planet to have experienced tectonic stresses and volcanic activity.

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Other terrestrial planets like Mars and Venus have also experienced tectonic stresses and volcanic activity.

Question 18

The current atmospheric concentration of carbon dioxide on Earth is at its highest in over a million years.

Accepted Answer

Scientific research shows that the current atmospheric concentration of carbon dioxide (CO2) is around 415 parts per million (ppm), which is higher than any recorded level in the past 800,000 years. Some evidence indicates that CO2 levels may not have been this high for millions of years.

Question 19

How does the size of a planet determine its internal temperature?

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Question 20

Summarize some of the evidence suggesting that Mars once had flowing water.

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Quiz 7: Earth and the Terrestrial Worlds