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Ch7 concept quiz
Question | Answer |
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The cores of the terrestrial worlds are made mostly of metal because ______. | metals sunk to the centers a long time ago when the interiors were molten throughout |
Which internal heat source still generates heat within the terrestrial worlds today? | Heat from radioactive decay. |
The reason that small planets tend to lose interior heat faster than larger planets is essentially the same as the reason that _________. | a large baked potato takes longer to cool than a small baked potato |
Suppose we had a device that allowed us to see Earth's interior. If we looked at a typical region of the mantle, what would we see happening? | not much - on human time scales, the mantle looks like solid rock |
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? | Mars's interior has cooled so much its molten core layer no longer undergoes convection. |
Which of the following most likely explains why Venus does not have a global magnetic field like Earth? | its rotation is too slow |
What are the two geological features that appear to set Earth apart from all the other terrestrial worlds? | plate tectonics and widespread erosion |
Which of the following general statements about Earth's atmosphere is not true? | The nitrogen and oxygen in Earth's atmosphere keep the surface pleasantly warm. |
Why is the sky blue (on Earth)? | Because molecules scatter blue light more effectively than red light. |
Which of the following best describes how the greenhouse effect works? | planet's surface absorbs visible sunlight and returns this absorbed energy to space as infrared light. Greenhouse gases slow the escape of this infrared radiation, which thereby heats the lower atmosphere. |
Suppose that Earth's atmosphere had no greenhouse gases. Then Earth's average surface temperature would be ________. | well below the freezing point of water |
Most of the Moon's surface is densely covered with craters, but we find relatively few craters within the lunar maria. What can we conclude? | The maria formed after the heavy bombardment ended. |
Which of the following best describes the geological histories of the Moon and Mercury? | Early in their histories, they suffered many impacts and experienced some volcanism and tectonics, but they now have little geological activity at all. |
What makes us think that Mars must once have had an atmosphere that was warmer and had higher surface pressure? | The atmosphere is too cold and thin for liquid water today, yet we see evidence that water flowed on the surface in the past. |
All the following statements about Mars are true. Which one might have led to a significant loss of atmospheric gas to space? | Mars lost any global magnetic field that it may once have had. |
Why is Mars red? | Chemical reactions between surface rock and atmospheric oxygen literally rusted the surface. |
All of the statements below are true. Which one gives the primary reason why the surface of Venus today is some 450°C hotter than the surface of Earth? | Venus has a much stronger greenhouse effect than Earth. |
Many scientists suspect that Venus has a stronger and thicker lithosphere than Earth. If this is true, which of the following could explain it? | The high surface temperature that has "baked out" all the liquid water from Venus's crust and mantle |
Which of the following best explain what we think happened to outgassed water vapor on Venus? | Ultraviolet light split the water molecules, and the hydrogen then escaped to space. |
Which of the following is the underlying reason why Venus has so little wind erosion? | its slow rotation |
All the following statements about Venus are true. Which one offers evidence of a global repaving about a billion years ago? | Venus has relatively few impact craters and these craters are distributed fairly evenly over the entire planet. |
Why are there fewer large impact craters on the Earth's seafloor than on the continents? | Seafloor crust is younger than continental crust, so it has had less time in which to suffer impacts. |
Why is Earth's continental crust lower in density than seafloor crust? | Continental crust is made as the lowest-density seafloor crust melts and erupts to the surface near subduction zones. |
Which two factors are most important to the existence of plate tectonics on Earth? | mantle convection and a thin lithosphere |
Why does Earth have so little carbon dioxide in its atmosphere compared to Venus? | Earth has just as much carbon dioxide as Venus, but most of it is locked up in carbonate rocks rather than being free in the atmosphere. |
Which two factors are critical to the existence of the carbon dioxide (CO2) cycle on Earth? | plate tectonics and liquid water oceans |
Suppose Earth were to cool down a little. How would the carbon dioxide cycle tend to restore temperatures to normal? | Cooler temperatures lead to slower formation of carbonate minerals in the ocean, so carbon dioxide released by volcanism builds up in the atmosphere and strengthens the greenhouse effect. |
Which of the following is not an expected consequence of global warming? | The entire Earth will warm up by the same amount. |
The choices below describe four hypothetical planets. Which one would you expect to have the hottest interior? (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.) | Size: twice as big as Earth. Distance from Sun: same as Mercury. Rotation rate: once every 6 months. |
What's the fundamental reason that Mars, unlike the Earth, has become virtually geologically dead? | its small size compared to Earth |
The choices below describe four hypothetical planets. Which one would you expect to have the most features of erosion? (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.) | Size: same as Venus. Distance from Sun: same as Mars. Rotation rate: once every 25 hours. |
Size: same as Venus. Distance from Sun: same as Mars. Rotation rate: once every 25 hours. | Size: same as the Moon. Distance from Sun: same as Mars. Rotation rate: once every 10 days. |