Astronomy Chapter 9
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.
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
The slowly increasing distance between South America and Africa is due to
...
Just as the surface area-to-volume ratio depends on size, so can other properties. To see how, suppose that your size suddenly doubled-that is, your height, width, and depth all doubled. (For example, if you were 5 feet tall before, you now are 10 feet tall.) The pressure on your weight-bearing joints depends on how much weight is supported by the surface area of each joint. How has this pressure changed?
2 times
Just as the surface area-to-volume ratio depends on size, so can other properties. To see how, suppose that your size suddenly doubled-that is, your height, width, and depth all doubled. (For example, if you were 5 feet tall before, you now are 10 feet tall.) What factor has your waist size increased?
2 times
Just as the surface area-to-volume ratio depends on size, so can other properties. To see how, suppose that your size suddenly doubled-that is, your height, width, and depth all doubled. (For example, if you were 5 feet tall before, you now are 10 feet tall.) How much more material will be required for your clothes? (Hint: Clothes cover the surface area of your body.)
4
Just as the surface area-to-volume ratio depends on size, so can other properties. To see how, suppose that your size suddenly doubled-that is, your height, width, and depth all doubled. (For example, if you were 5 feet tall before, you now are 10 feet tall.) By what factor has your weight increased? (Hint: Weight depends on the volume of your body.)
8
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.
In the context of plate tectonics, what is a subduction zone?
A place where a seafloor plate is sliding under a continental plate.
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
Assuming that features you see on Mars are similar to features found on Earth, what would a casual inspection of the interactive photo of Mars lead you to suspect about water on Mars?
Surface water only exists as frozen ice.
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.
Which of the following is an example of convection?
Warm air expanding and rising while cooler air contracts and fall.
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.
Australia is composed of relatively old and thick
continental crust
From center to surface, which of the following correctly lists the interior layers of a terrestrial world?
core, mantle, crust
________found in the Atlantic Ocean between North America and Europe is composed of dense and relatively young rock.
sea floor crust
Layered _________exposed by erosion can be seen when looking at the Grand Canyon in the United States
sedimentary rock
The extremely deep ocean Marianas Trench is a result of
subduction
Typical motions of one plate relative to another are 1 centimeter per year, At this rate, how long would it take for two continents 3000 kilometers apart to collide?
t = 3.0×108 yr
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
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.
What observational evidence supports the idea that Mercury once shrank by some 20 kilometers in radius?
the presence of many long, tall cliffs
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
On how many of the five terrestrial worlds has erosion been an important process? (Be sure that you explain why erosion is important on this many worlds and not more.)
two
Which of the following is the underlying reason why Venus has so little wind erosion?
venus has a slow rotation
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
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
How many of the five terrestrial worlds have surfaces being constantly reshaped by plate tectonics?
one
Which of the following best describes the lunar maria?
relatively smooth, flat plains on the Moon
What are the two geological features that appear to set Earth apart from all the other terrestrial worlds?
plate tectonics and widespread erosion
In general, which things below are affected by a magnetic field?
Charged particles or magnetized materials (such as iron).
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
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.
Which of the following places is the result of volcanoes erupting over a hot spot in the mantle?
Hawaii
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.
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.
Which describes our understanding of flowing water on Mars?
It was important once, but no longer.
Which of the following most likely explains why Venus does not have a global magnetic field like Earth?
Its rotation is too slow
Which of the following Mars surface features provides dramatic evidence that volcanism has played a role in shaping the surface of Mars?
Olympus Mons
What do we conclude if a planet has few impact craters of any size?
Other geological processes have wiped out craters.
How does seafloor crust differ from continental crust?
Seafloor crust is thinner, younger, and higher in density.
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.
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.
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.
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.
Which of the following is NOT an example of tectonics?
The gradual disappearance of a crater rim as a result of wind and rain.
Which of the following is not an example of tectonics?
The gradual disappearance of a crater rim as a result of wind and rain.
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 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.
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.
On average, how fast do the plates move on the Earth?
a few centimeters per year
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
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.
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
Old Faithful Geyser at Yellowstone National Park in the United States acquires its energy from
a hot spot
Olympus Mons is ______.
a huge shield volcano on Mars
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
A terrestrial world's lithosphere is ________.
a layer of relatively strong, rigid rock, encompassing the crust and part of the mantle
In the context of plate tectonics, what is a subduction zone?
a place where a seafoor plate is sliding under a continental plate
In general, what kind of planet would you expect to have the thickest lithosphere?
a small planet
Based on Planet Z's size, orbital distance, and rotation rate, which of the following properties is it likely to have?
active volcanos, active tectonics, an atmosphere produced by outgassing
What is the name of the outer rigid layer of a planet?
lithosphere
Which two factors are most important to the existence of plate tectonics on Earth?
mantle convection and a thin lithosphere
The earthquakes that occur in Southern California generally occur above a
fault
How many of the terrestrial worlds have lava plains or shield volcanoes?
five
Which internal heat source still generates heat within the terrestrial worlds today?
heat from radioactive decay
When you zoom in on the section labeled "Southern Highlands," which geologic processes are most clearly evident?
impact cratering and erosion
The processes responsible for virtually all surface geology are _________.
impact cratering, volcanisms, tectonics, and erosion
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
What's the fundamental reason that Mars, unlike the Earth, has become virtually geologically dead?
its small size compared to Earth
