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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 |
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Which of the following is not generally true of all the terrestrial world lithospheres? |
The lithosphere is broken into a set of large plates that float upon the softer rock below. |
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Which internal heat source still generates heat within the terrestrial worlds today? |
Heat from radioactive decay. |
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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 |
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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 |
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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 that its molten core layer no longer undergoes convection. |
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Which of the following most likely explains why Venus does not have a global magnetic field like Earth? |
Its rotation is too slow. |
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You discover an impact crater that is 10 kilometers across. Which of the following can you conclude? |
It was created by the impact of an object about 1 kilometer across. |
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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. |
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Which of the following is the underlying reason why Venus has so little wind erosion? |
its slow rotation |
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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. |
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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. |
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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. |
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What are the two geological features that appear to set Earth apart from all the other terrestrial worlds? |
plate tectonics and widespread erosion |
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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. |
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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. |
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Which two factors are most important to the existence of plate tectonics on Earth? |
mantle convection and a thin lithosphere |
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What’s the fundamental reason that Mars, unlike the Earth, has become virtually geologically dead? |
its small size compared to Earth |
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Based on all we know about the terrestrial worlds, what single factor appears to play the most important role in a terrestrial planet’s geological destiny? |
its size |
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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. |
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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.) |
Size: same as the Moon. Distance from Sun: same as Mars. Rotation rate: once every 10 days. |
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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. |
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Suppose we use a baseball to represent Earth. On this scale, the other terrestrial worlds (Mercury, Venus, the Moon, and Mars) would range in size approximately from that of ______. |
a golf ball to a baseball |
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From center to surface, which of the following correctly lists the interior layers of a terrestrial world? |
Core, mantle, crust. |
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What do we mean when we say that the terrestrial worlds underwent differentiation? |
When their interiors were molten, denser materials sank toward their centers and lighter materials rose toward their surfaces. |
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A terrestrial world’s lithosphere is ________. |
a layer of relatively strong, rigid rock, encompassing the crust and part of the mantle |
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The major processes that heat the interiors of the terrestrial worlds are: |
(1) Heat deposited as the planets were built from planetesimals; (2) heat deposited as the planets underwent differentiation; (3) heat released by radioactive decay. |
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Which of the following is an example of convection? |
Warm air expanding and rising while cooler air contracts and fall. |
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What are the basic requirements for a terrestrial world to have a global magnetic field? |
A core layer of molten, convecting material and sufficiently rapid rotation. |
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In general, which things below are affected by a magnetic field? |
Charged particles or magnetized materials (such as iron). |
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The processes responsible for virtually all surface geology are _________. |
impact cratering, volcanisms, tectonics, and erosion |
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Which of the following best describes the lunar maria? |
relatively smooth, flat plains on the Moon |
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In the context of planetary geology, what do we mean by outgassing? |
the release by volcanism of gases that had been trapped in a planetary interior |
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Which of the following is not an example of tectonics? |
The gradual disappearance of a crater rim as a result of wind and rain. |
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Why does the Moon have a layer of "powdery soil" on its surface? |
It is the result of countless tiny impacts by small particles striking the Moon. |
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What observational evidence supports the idea that Mercury once shrank by some 20 kilometers in radius? |
the presence of many long, tall cliffs |
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Olympus Mons is ______. |
a huge shield volcano on Mars |
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Which of the following does not provide evidence that Mars once had abundant liquid water on its surface? |
the presence of canali, discovered in the late 1800s by Giovanni Schiaparelli and mapped by Percival Lowell. |
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Based on its surface features, the most important event on Venus in the past billion years or so was _______. |
a global "repaving" that erased essentially all the surface features that had existed earlier. |
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On average, how fast do the plates move on the Earth? |
a few centimeters per year |
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How does seafloor crust differ from continental crust? |
Seafloor crust is thinner, younger, and higher in density. |
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In the context of plate tectonics, what is a subduction zone? |
A place where a seafloor plate is sliding under a continental plate. |
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Which of the following places is the result of volcanoes erupting over a hot spot in the mantle? |
Hawaii |
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