Astronomy Ch. 7

Which heat source continues to contribute to Earth's internal heat? accretion radioactive decay sunlight

Which of a planet's fundamental properties has the greatest effect on its level of volcanic and tectonic activity? size distance from the Sun rotation rate

What do we conclude if a planet has few impact craters of any size? The planet was never bombarded by asteroids or comets. Its atmosphere stopped impactors of all sizes. Other geological processes have wiped out craters.

How many of the five terrestrial worlds are considered "geologically dead"? none two four

Which describes our understanding of flowing water on Mars? It was never important. It was important once, but no longer. It is a major process on the Martian surface today.

The oxygen in Earth's atmosphere was released by volcanic outgassing. the CO2 cycle. life.

Where is the most CO2 that has outgassed from Earth's volcanoes? in the atmosphere escaped to space locked up in rocks

The energy that warms Earth's surface comes primarily in the form of __________. heat from Earth's interior visible light from the Sun infrared light from the Sun ultraviolet light from the Sun heat from the Sun

Earth's temperature remains fairly steady, which means that Earth must return nearly the same amount of energy to space that it receives from the Sun. In what forms does Earth return most of this energy to space? visible light emitted by the surface and atmosphere infrared light emitted by the surface and atmosphere visible light reflected by clouds ultraviolet light reflected by the surface visible light reflected by the surface

Greenhouse gases in the atmosphere, such as carbon dioxide and water vapor, make Earth warmer than it would be otherwise because these gases __________. reflect visible light coming from the Sun absorb infrared light emitted by the surface absorb visible light coming from the Sun form clouds that emit thermal radiation

According to scientists, the naturally occurring greenhouse effect makes Earth about 31∘C warmer than it would be if there were no greenhouse gases in our atmosphere. How do scientists "know" what Earth's temperature would be without greenhouse gases? They assume that this temperature would be about the same as the temperature of Mars, which has much less of an atmosphere than Earth. Ancient fossils allow them to infer Earth's temperature at a time before our atmosphere contained greenhouse gases. They estimate it by averaging guesses made by many individual scientists. They calculate this temperature from Earth's reflectivity and distance from the Sun.

All of the following statements are true. Which one provides strong observational support for the claim that greenhouse gases make a planet warmer than it would be otherwise? Earth has a higher average temperature than Mars. Earth is the only planet with an ozone layer in its atmosphere. Mercury is much hotter than the Moon. Venus has a higher average temperature than Mercury.

Based solely on an understanding of the greenhouse effect, which one of the following statements is true? Global warming poses a grave threat to our future. We do not yet understand the greenhouse effect well enough to make predictions about how it affects our planet. We should expect an increase in the greenhouse gas concentration to lead to global warming. Humans are causing global warming.

The slowly increasing distance between South America and Africa is due to ________ _________.

Old Faithful Geyser at Yellowstone National Park in the United States acquires its energy from a ___ ____.

Layered ___________ ____ exposed by erosion can be seen when looking at the Grand Canyon in the United States.

Australia is composed of relatively old and thick ___________ _____.

The extremely deep ocean Marianas Trench is a result of __________.

________ _____ found in the Atlantic Ocean between North America and Europe is composed of dense and relatively young rock.

The earthquakes that occur in Southern California generally occur above a _____.

The cores of the terrestrial worlds are made mostly of metal because ________. the core contained lots of radioactive elements that decayed into metals metals sunk to the centers a long time ago when the interiors were molten throughout over billions of years, convection gradually brought dense metals downward to the core the terrestrial worlds as a whole are made mostly of metal

Which internal heat source still generates heat within the terrestrial worlds today? heat of accretion. heat from differentiation heat from convection 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 ________. Earth contains more metal than the Moon thunderstorms tend to form on hot summer days a large baked potato takes longer to cool than a small baked potato gas bubbles form and rise upward in boiling water

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. Mars rotates much slower than the Earth. The Martian core is made of rock, while Earth's core is made of metal. Mars is too far from the Sun to have a global magnetic field.

Which of the following most likely explains why Venus does not have a global magnetic field like Earth? It has too thick of an atmosphere. It does not have a metallic core. Its rotation is too slow. Unlike Earth, Venus does not have a liquid outer core.

What are the two geological features that appear to set Earth apart from all the other terrestrial worlds? plate tectonics and widespread erosion a dense core and plate tectonics mantle convection and a thick atmosphere significant volcanism and tectonics

Why is the sky blue (on Earth)? because molecules scatter blue light more effectively than red light because deep space is blue in color because the Sun emits mostly blue light because molecules scatter red light more effectively than blue light No one knows-this is one of the great mysteries of science.

Which of the following best describes how the greenhouse effect works? A 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. The greenhouse effect is caused primarily by ozone, which absorbs ultraviolet light and thereby makes the atmosphere much hotter than it would be otherwise. Greenhouse gases absorb X-rays and ultraviolet light from the Sun, and this absorbed radiation then heats the atmosphere and the surface. Greenhouse gases absorb infrared light coming from the Sun, and this absorbed sunlight heats the lower atmosphere and the surface.

If the polar ice decreases, what would happen, and why? warming, because more sunlight is reflected cooling, because more sunlight is reflected warming, because more sunlight is absorbed cooling, because melted ice cools things off

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. Erosion affects the maria more than it affects other regions of the Moon. The regions of the maria were hit by fewer impacts than the densely cratered regions. The maria formed within the past 1 billion years.

Which of the following best describes the geological histories of the Moon and Mercury? Impact cratering shaped these worlds early in their histories. Then, during the past few million years, they were reshaped by episodes of volcanism and tectonics. Impact cratering is the only major geological process that has affected their surfaces. All four geological processes were important in their early histories, but only impact cratering still reshapes their surfaces today. 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 presence of inactive volcanoes on Mars tells us that there must once have been a lot of outgassing, and hence a thicker atmosphere. We think it for purely theoretical reasons, based on calculations showing that the Sun has brightened with time. The atmosphere is too cold and thin for liquid water today, yet we see evidence that water flowed on the surface in the past. The fact that parts of Mars have a lot of craters tell us that Mars must once have been much warmer.

All the following statements about Mars are true. Which one might have led to a significant loss of atmospheric gas to space? The axis tilt of Mars is thought to change significantly with time. Mars probably once had a much higher density of greenhouse gases in its atmosphere than it does today. Mars lost any global magnetic field that it may once have had. Outgassed water molecules are split apart by ultraviolet light, and the oxygen then reacts chemically with surface rock on Mars.

Why is Mars red? The red color is caused by water ice chemically bound in surface rock. Chemical reactions between surface rock and atmospheric oxygen literally rusted the surface. Martian volcanoes released a much redder lava than volcanoes on Earth. The red color of Mars is a result of the scattering of light in the Martian sky.

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 higher reflectivity than Earth. Venus is only about 73% as far from the Sun as Earth. Venus has a much stronger greenhouse effect than Earth. Venus has a higher atmospheric pressure 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 smaller size of Venus, which has allowed it to lose much more internal heat than Earth the high surface temperature that has "baked out" all the liquid water from Venus's crust and mantle the slow rotation of Venus the apparent lack of plate tectonics on Venus

Which of the following best explain what we think happened to outgassed water vapor on Venus? It turned into carbon dioxide by reacting with nitrogen in Venus's atmosphere. Ultraviolet light split the water molecules, and the hydrogen then escaped to space. It is frozen as water ice in craters near the poles. Water was removed from the atmosphere by chemical reactions with surface rock.

Which of the following is the underlying reason why Venus has so little wind erosion? its small size its relatively close distance to the Sun its thick atmosphere 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's largest features are three elevated regions that look somewhat like continents. Venus appears to lack any water that could lubricate the flow of rock in its crust and mantle. Venus has many circular features, called coronae, which appear to be tectonic in origin. 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? Most impacts occur on the land. Seafloor crust is younger than continental crust, so it has had less time in which to suffer impacts. Erosion erases impact craters must faster on the ocean bottom than on land. The oceans slow large impactors and prevent them from making craters.

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. Earth once had a lot of carbon dioxide, but it was lost to space during the heavy bombardment early in our solar system's history. Chemical reactions turned Earth's carbon dioxide into nitrogen. Earth's volcanoes outgassed far less carbon dioxide than those on Venus.

Suppose Earth were to cool down a little. How would the carbon dioxide cycle tend to restore temperatures to normal? Cooler temperatures cause volcanoes to become more active, so they release more carbon dioxide into the atmosphere than they do when temperatures are warmer. Cooler temperatures allow carbon dioxide to form rain and rain out of the atmosphere. Cooler temperatures mean more ice and more erosion, which somehow makes the planet warm up. 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? melting of polar ice and glaciers The entire Earth will warm up by the same amount. an increase in the severity of winter blizzards an increase in the number and intensity of hurricanes

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: same as Mars. Distance from Sun: same as Earth. Rotation rate: once every 18 hours. Size: same as the Moon. Distance from Sun: same as Mars. Rotation rate: once every 10 days. Size: same as Venus. Distance from Sun: same as Mars. Rotation rate: once every 25 hours. Size: twice as big as Earth. Distance from Sun: same as Mercury. Rotation rate: once every 6 months.

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: twice as big as Earth. Distance from Sun: same as Mercury. Rotation rate: once every 6 months. Size: same as the Moon. Distance from Sun: same as Mars. Rotation rate: once every 10 days. Size: same as Venus. Distance from Sun: same as Mars. Rotation rate: once every 25 hours. Size: same as Mars. Distance from Sun: same as Earth. Rotation rate: once every 18 hours.

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: twice as big as Earth. Distance from Sun: same as Mercury. Rotation rate: once every 6 months. Size: same as the Moon. Distance from Sun: same as Mars. Rotation rate: once every 10 days. Size: same as Mars. Distance from Sun: same as Earth. Rotation rate: once every 18 hours. Size: same as Venus. Distance from Sun: same as Mars. Rotation rate: once every 25 hours.

From center to surface, which of the following correctly lists the interior layers of a terrestrial world? mantle, core, crust core, crust, lithosphere core, mantle, crust mantle, crust, core

What do we mean when we say that the terrestrial worlds underwent differentiation? Their surfaces show a variety of different geological features resulting from different geological processes. The five terrestrial worlds all started similarly but ended up looking quite different. When their interiors were molten, denser materials sank toward their centers and lighter materials rose toward their surfaces. They lost interior heat to outer space.

The processes responsible for virtually all surface geology are ________. eruptions, lava flows, and outgassing accretion, differentiation, and radioactive decay convection, conduction, and radiation impact cratering, volcanisms, tectonics, and erosion

What is a magnetosphere? the uppermost layer of any planetary atmosphere the region in a planet's atmosphere in which auroras occur a region of space around a planet in which the planet's magnetic field can trap charged particles the layer of a planet in which its magnetic field is generated

In general, which things below are affected by a magnetic field? charged particles or magnetized materials (such as iron) iron-bearing minerals only rocks of all types gases and liquids

Why does the Moon have a layer of "powdery soil" on its surface? It exists because the Moon accreted from powdery material after a giant impact blasted the Earth. It is the result of countless tiny impacts by small particles striking the Moon. It is made by the same processes that make powdery sand on Earth. Recent, large impacts shattered lunar rock to make this soil.

Which of the following best describes the lunar maria? mountainous regions on the Moon relatively smooth, flat plains on the Moon densely cratered regions on the Moon frozen oceans of liquid water on the Moon

What observational evidence supports the idea that Mercury once shrank by some 20 kilometers in radius? the presence of many impact craters the presence of many long, tall cliffs Mercury's unusually high density the characteristics of the Caloris Basin

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 the presence of features that look like dried up river beds the presence of what looks like sedimentary layers in some crater bottoms the presence of very old craters that appear to have been eroded by rain

What is the importance of the carbon dioxide (CO2) cycle? It allows for an ultraviolet-absorbing stratosphere. It will prevent us from suffering any consequences from global warming. It regulates the carbon dioxide concentration of our atmosphere, keeping temperatures moderate. It makes the growth of continents possible.

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 composition its size its distance from the Sun whether or not it has liquid water

Rank the five terrestrial worlds in order of size from smallest to largest. Mercury, Moon, Mars, Earth, Venus Mercury, Venus, Earth, Moon, Mars Moon, Mercury, Venus, Earth, Mars Mercury, Moon, Venus, Earth, Mars Moon, Mercury, Mars, Venus, Earth

The terrestrial planet cores contain mostly metal because radioactivity created metals in the core from the decay of uranium. metals sank to the center during a time when the interiors were molten throughout. metals condensed first in the solar nebula and the rocks then accreted around them. the entire planets are made mostly of metal. convection carried the metals to the core.

When we see a region of a planet that is not as heavily cratered as other regions, we conclude that the planet formed after the age of bombardment and missed out on getting hit by leftover planetesimals. there is little volcanic activity to create craters. the surface in the region is younger than the surface in more heavily cratered regions. the planet is rotating very slowly and only one side was hit by impactors. the surface in the region is older than the surface in more heavily cratered regions.

Which of the following describes volcanism? the excavation of bowl-shaped depressions by asteroids or comets striking a planet's surface the eruption of molten rock from a planet's interior to its surface the disruption of a planet's surface by internal stresses the wearing down or building up of geological features by wind, water, ice, and other phenomena of planetary weather

Volcanism is more likely on a planet that doesn't have an atmosphere or oceans. has high internal temperatures. is struck often by meteors and solar system debris. is closer to the Sun.

Which of the following worlds has the most substantial atmosphere? Mercury Venus the Moon Mars Earth

Which of the following planets has the least substantial atmosphere? Neptune Earth Venus Mars Mercury

Where is most of the water on Mars? distributed evenly throughout its atmosphere in its polar caps and subsurface ground ice frozen on the peaks of its tall volcanoes in deep underground deposits in its clouds

Why is Mars red? It is made primarily of red clay. Its surface is made of ices that absorb red light. Its surface is made of ices that absorb blue light. Its surface rocks were rusted by oxygen. Its atmosphere scatters blue light more effectively than red light.

Spacecraft have landed on all the terrestrial worlds except Moon. Mercury. Mars. Venus.

In what ways is Earth different from the other terrestrial planets? It has oxygen in its atmosphere. Life can be found almost everywhere. Most of its surface is covered with liquid water. Its lithosphere is broken into plates that move around. All of the above are true.