Test 2 Chapter 6
11) The Cassini mission to Saturn consists of ________. A) an orbiter that orbits Saturn and a probe that descended to the surface of Titan B) a large spacecraft that flew by Saturn on its way to other planets C) an orbiter that orbits Saturn and a probe that descended into Saturn's atmosphere D) a spacecraft that orbits Saturn and a sample return mission that landed on Titan, scooped up a surface sample, and will return it to Earth
Answer: A
11) The following statements are all true. Which one counts as an "exception to the rule" in being unusual for our solar system? A) Earth has a large moon. B) Venus does not have a moon. C) Jupiter has a very small axis tilt. D) Saturn has no solid surface.
Answer: A
24) What is the giant impact hypothesis for the origin of the Moon? A) The Moon formed from material blasted out of the Earth's mantle and crust by the impact of a Mars-size object. B) The Moon formed when two gigantic asteroids collided with one another. C) The Moon originally was about the same size as Earth, but a giant impact blasted most of it away so that it ended up much smaller than Earth. D) The Moon formed just like the Earth, from accretion in the solar nebula.
Answer: A
24) Why are terrestrial planets more dense than the jovian planets? A) Only dense materials could condense in the inner solar nebula. B) The Sun's gravity pulled dense materials into the inner solar system. C) Gravity compresses terrestrial planets to a higher degree, making them denser. D) Since the jovian planets are more massive than the terrestrials, the jovians must be more dense.
Answer: A
25) Suppose you find a rock that contains 10 micrograms of radioactive potassium-40, which has a half-life of 1.25 billion years. By measuring the amount of its decay product (argon-40) present in the rock, you conclude that there must have been 80 micrograms of potassium-40 when the rock solidified. How old is the rock? A) 3.75 billion years B) 1.25 billion years C) 2.5 billion years D) 5.0 billion years
Answer: A
5) Which of the following statements about Mars is not true? A) We could survive on Mars without spacesuits, as long as we brought oxygen in scuba tanks. B) We have landed spacecraft on its surface. C) It is considered part of our inner solar system. D) It is frozen today, but once had flowing water.
Answer: A
5) Which of the following statements about the recently-discovered object Eris is not true? A) It is thought to be the first example ever discovered of a new class of objects. B) It has at least one moon. C) It lies well beyond Pluto and Neptune. D) It orbits the Sun in the same direction as the other planets.
Answer: A
6) Mars has two moons that are most similar in character to ________. A) small asteroids B) comets C) Earth's Moon D) particles in the rings of Saturn
Answer: A
6) The planet in our solar system with the highest average surface temperature is ________. A) Venus B) Mercury C) Earth D) Neptune
Answer: A
7) Considering only the tilt of their axis, which planet listed below would have the most extreme seasons? A) Uranus B) Mars C) Earth D) Jupiter
Answer: A
7) The terrestrial planets are made almost entirely of elements heavier than hydrogen and helium. According to modern science, where did these elements come from? A) They were produced by stars that lived and died before our solar system was born. B) They were produced in the core of the Sun. C) They have been present in the universe since its birth. D) They were made by chemical reactions in interstellar gas.
Answer: A
8) In what way is Pluto more like a comet than a planet? A) It is made mostly of rock and ice. B) It sometimes enters the inner solar system. C) It has a long tail. D) It has a moon.
Answer: A
13) When we say that jovian planets contain significant amounts of hydrogen compounds, we mean all the following chemical compounds except ________. A) carbon dioxide B) water C) ammonia D) methane
Answer: A
14) According to our theory of solar system formation, which law best explains why the central regions of the solar nebula got hotter as the nebula shrank in size? A) the law of conservation of energy B) the law of conservation of angular momentum C) Newton's third law D) the two laws of thermal radiation
Answer: A
14) In essence, the solar nebular theory states that ________. A) our solar system formed from the collapse of an interstellar cloud of gas and dust B) nebulae are clouds of gas and dust in space C) the planets each formed from the collapse of its own separate nebula D) The nebular theory is a discarded idea that imagined planets forming as a result of a near- collision between our Sun and another star.
Answer: A
15) According to our present theory of solar system formation, which of the following best explains why the solar nebula ended up with a disk shape as it collapsed? A) It flattened as a natural consequence of collisions between particles in the nebula. B) It was fairly flat to begin with, and retained this flat shape as it collapsed. C) The force of gravity pulled the material downward into a flat disk. D) The law of conservation of energy contributed to how a disk shape formed.
Answer: A
15) Based on studies of the composition of stars and interstellar gas clouds, what was the approximate chemical composition of the solar nebula? A) 98% hydrogen and helium, 2% everything else B) 50% hydrogen and helium, 50% everything else C) 98% hydrogen, 2% helium D) roughly equal proportions of hydrogen, helium, water, and methane
Answer: A
15) Where are most of the known asteroids found? A) between the orbits of Mars and Jupiter B) in the Kuiper belt C) in the Oort cloud D) between the orbits of the jovian planets E) between the orbits of the terrestrial planets
Answer: A
16) What is the primary reason we divide the ingredients of the solar nebula into four categories (hydrogen/helium gas; hydrogen compound; rock; metal)? A) The temperature at which these materials condense into a solid varies considerably. B) The atomic mass number of these materials differs considerably. C) The abundance of these materials depended on their location in the solar nebula. D) The amount of energy required to ionize these materials varies considerably.
Answer: A
16) Why would we expect to find a higher percentage of heavy elements in a young star, as opposed to an older star? A) Heavy elements are produced by stars living and dying, so more heavy elements get incorporated into future generations of stars. B) Heavy elements are destroyed by stars as they age. C) Heavy elements were more common long ago before stars began forming. D) Light elements are the result of heavy elements decaying over time.
Answer: A
17) According to our present theory of solar system formation, which of the following statements about the growth of terrestrial and jovian planets is not true? A) The jovian planets began from planetesimals made only of ice, while the terrestrial planets began from planetesimals made only of rock and metal. B) Both types of planets began with planetesimals growing through the process of accretion, but only the jovian planets were able to capture hydrogen and helium gas from the solar nebula. C) Swirling disks of gas, like the solar nebula in miniature, formed around the growing jovian planets but not around the growing terrestrial planets. D) The terrestrial planets formed inside the frost line of the solar nebula and the jovian planets formed beyond it.
Answer: A
18) What can we conclude from the fact that Neptune's large moon Triton orbits in a direction opposite to the direction in which Neptune rotates? A) Triton must be made mostly of ice. B) Triton must have formed as the result of a giant impact. C) Triton must have been captured by Neptune. D) Triton must have formed in place around Neptune. E) Triton must be more dense than Neptune.
Answer: C
2) How is Einstein's famous equation, E = mc2, important in understanding the Sun? A) The Sun has a magnetic field strong enough to influence the atmospheres of the planets. B) The Sun's surface temperature is about 6,000° Celsius. C) The Sun generates its energy by converting 4 million tons of mass to energy each second. D) This equation represents how difficult science is, so understanding the Sun is difficult as well.
Answer: C
2) Where does nuclear fusion occur in the Sun? A) on the surface B) anywhere below the surface C) in its core D) just above the visible surface E) all of the above
Answer: C
36) What do meteorites reveal about the solar system? A) They reveal that meteorites are about the same age as most Earth rocks. B) Nothing, because they come from other star systems. C) They reveal that the solar system once contained 10 planets. D) They reveal that the age of the solar system is approximately 4.6 billion years. E) They reveal that the early solar system consisted mostly of hydrogen and helium gas.
Answer: D
4) Which of the following is not true of Mercury? A) It has no moons. B) At any given time, about half the planet is colder than Antarctica. C) Its surface is heavily cratered. D) Mercury has a density greater than that of Earth.
Answer: D
4) Which of the following observations of an extrasolar planet system would be inconsistent with the nebular theory of planet formation? A) a system in which some planets have small moons orbiting in a direction opposite to the planet's rotation B) a system which has two terrestrial planets close in and two gas giants farther out C) a system in which the planets rotate in the same direction as they orbit D) a system in which all the planets orbit in completely different planes
Answer: D
8) Which of the following statements does not apply to the formation of gas giants like Jupiter, compared to terrestrial planets? A) caused icy planetesimals to slingshot away from the Sun, to become Oort cloud comets B) formed in a region with lower orbital speeds C) accreted from icy planetesimals D) surface dramatically altered during bombardment E) formed in regions cold enough for water to freeze
Answer: D
16) Which of the following is furthest from the Sun? A) Pluto B) Eris C) an asteroid in the asteroid belt D) a comet in the Kuiper belt E) a comet in the Oort cloud
Answer: E
31) Based on our current theory of Earth's formation, the water we drink likely comes from A) ice that condensed in the solar nebula in the region where Earth formed. B) chemical reactions that occurred in Earth's crust after Earth formed. C) chemical reactions that occurred in Earth's core after Earth formed. D) material left behind during the giant impact that formed the Moon. E) water bearing planetesimals that impacted Earth.
Answer: E
33) Which of the apparent exceptions to the solar nebular theory cannot be explained by a giant impact event? A) the formation of the Moon B) the large metallic core of Mercury C) the backward rotation of Venus D) the extreme axis tilt of Uranus E) the orbit of Triton in the opposite direction to Neptune's rotation
Answer: E
4) Which object, other than Earth, has visible water on its surface? A) Mercury B) Venus C) Mars D) the Moon E) none of the above
Answer: E
6) Which planet has a ring system? A) Jupiter B) Saturn C) Uranus D) Neptune E) all of the above
Answer: E
7) Which planet could an astronaut visit without the need for a spacesuit (and survive)? A) Mercury B) Venus C) the Moon D) Mars E) None; an astronaut would need a spacesuit to survive a visit to any other planet in the solar system.
Answer: E
9) Which jovian planet does not have rings? A) Jupiter B) Neptune C) Uranus D) Mars E) All the jovian planets have rings.
Answer: E
17) According to our theory of solar system formation, what three major changes occurred in the solar nebula as it shrank in size? A) It got hotter, its rate of rotation increased, and it flattened into a disk. B) Its mass, temperature, and density all increased. C) It gained energy, it gained angular momentum, and it flattened into a disk. D) Its gas clumped up to form the terrestrial planets, nuclear fusion produced heavy elements to make the jovian planets, and central temperatures rose to more than a trillion Kelvin.
Answer: A
18) Many meteorites appear to have formed very early in the solar system's history. How do these meteorites support our theory about how the terrestrial planets formed? A) The meteorites' appearance and composition is just what we'd expect if metal and rock condensed and accreted as our theory suggests. B) The meteorites' sizes are just what we'd expect if metal and rock condensed and accreted as our theory suggests. C) Their overall composition is just what we believe the composition of the solar nebula to have been: mostly hydrogen and helium. D) Their appearance and composition matches what we observe in comets today, suggesting that they were once pieces of icy planetesimals.
Answer: A
18) Which of the following types of material can condense into what we call ice at low temperatures? A) hydrogen compounds B) hydrogen and helium C) rock D) metal
Answer: A
19) According to our present theory of solar system formation, which of the following lists the major ingredients of the solar nebula in order from the most abundant to the least abundant? A) hydrogen and helium gas; hydrogen compounds; rock; metal B) hydrogen compounds; hydrogen and helium gas; metal; rock C) hydrogen and helium gas; rock; metal; hydrogen compounds D) hydrogen; water; methane; helium
Answer: A
2) Suppose you view the solar system from high above Earth's North Pole. Which of the following statements about planetary orbits will be true? A) All the planets orbit counterclockwise around the Sun. B) The inner planets orbit the Sun counterclockwise while the outer planets orbit the Sun clockwise. C) All the planets except Uranus orbit the Sun counterclockwise; Uranus orbits in the opposite direction. D) The inner planets orbit the Sun clockwise while the outer planets orbit the Sun counterclockwise.
Answer: A
20) According to our present theory of solar system formation, how did Earth end up with enough water to make oceans? A) The water was brought to the forming Earth by planetesimals that accreted beyond the orbit of Mars. B) The water was brought to the forming Earth by planetesimals that accreted near Earth's orbit. C) The water was formed by chemical reactions among the minerals in the Earth's core. D) Earth formed at a distance from the Sun at which liquid water happened to be plentiful in the solar nebula.
Answer: A
20) What do we mean by the frost line when we discuss the formation of planets in the solar nebula? A) It is a circle at a particular distance from the Sun, beyond which the temperature was low enough for ices to condense. B) It is another way of stating the temperature at which water freezes into ice. C) It marks the special distance from the Sun at which hydrogen compounds become abundant; closer to the Sun, there are no hydrogen compounds. D) It is the altitude in a planet's atmosphere at which snow can form.
Answer: A
21) According to our present theory of solar system formation, why were solid planetesimals able to grow larger in the outer solar system than in the inner solar system? A) because only metal and rock could condense in the inner solar system, while ice also condensed in the outer solar system B) because the Sun's gravity was stronger in the outer solar system, allowing more solid material to collect C) because gas in the outer solar system contained a larger proportion of rock, metal, and hydrogen compounds than the gas in the inner solar system D) because only the outer planets captured hydrogen and helium gas from the solar nebula
Answer: A
21) What do we mean by accretion in the context of planet formation? A) the growth of planetesimals from smaller solid particles that collided and stuck together B) the formation of moons around planets C) the solidification of ices, rocks, and metal from the gas of the solar nebular D) the growth of the Sun as the density of gas increased in the center of the solar nebula
Answer: A
22) According to our basic scenario of solar system formation, why do the jovian planets have numerous large moons? A) As the growing jovian planets captured gas from the solar nebula, the gas formed swirling disks around them, and moons formed from condensation accretion within these disks. B) Because of their strong gravity, the jovian planets were able to capture numerous asteroids that happened to be passing nearby, and these became the major moons of the jovian planets. C) The large moons of the jovian planets originally formed in the inner solar system, and these moons then migrated out to join up with the jovian planets. D) The many moons of the jovian planets remains one of the unexplained mysteries of the formation of our solar system.
Answer: A
22) According to our theory of solar system formation, what are asteroids and comets? A) leftover planetesimals that never accreted into planets B) the shattered remains of collisions between planets C) chunks of rock or ice that condensed after the planets and moons finished forming D) chunks of rock or ice that were expelled from planets by volcanoes
Answer: A
22) Which of the following lists the composition of the solar nebula from highest to lowest percentage of mass? A) light gases (H, He), hydrogen compounds (H2O, CH4, NH3), rocks, metals B) hydrogen compounds (H2O, CH4, NH3), light gases (H, He), rocks, metals C) light gases (H, He), hydrogen compounds (H2O, CH4, NH3), metals, rocks D) hydrogen compounds (H2O, CH4, NH3), light gases (H, He), metals, rocks E) hydrogen compounds (H2O, CH4, NH3), rocks, metals, light gases (H, He) Answer: A
Answer: A
26) What kind of material in the solar nebula could condense at temperatures as high as 1,500 K, such as existed in the inner region of the nebula? A) rocks B) metals C) silicon-based minerals D) hydrogen compounds E) molecules such as methane and ammonia
Answer: B
28) Observations of young stars (as well as theory) tell us that when the Sun was young, the solar wind A) was weaker than it is today. B) was stronger than it is today. C) was about the same strength as it is today. D) was nonexistent. E) had a different composition than it does today.
Answer: B
30) According to our theory of solar system formation, why do we find some exceptions to the general rules and patterns of the planets? A) Our theory is not quite correct because it cannot explain these exceptions. B) Most of the exceptions are the result of giant impacts or close gravitational encounters. C) The exceptions probably represent objects that formed recently, rather than early in the history of the solar system. D) The exceptions probably represent objects that were captured by our solar system from interstellar space. E) The exceptions are probably the result of the Sun passing very close to another star billions of years ago.
Answer: B
39) Why can we assume that a rock sample containing argon-40 had none of this isotope when the rock initially formed? A) Argon-40 has a very short half-life so it is unlikely to be in an original rock sample. B) Argon-40 is a gas that does not combine with other elements, so it would not be present in a rock when it formed. C) Argon-40 can only be made in supernova explosions. D) Argon-40 has a higher condensation temperature than most rocks.
Answer: B
40) Why do Earth rocks have much younger ages than most meteorites? A) Earth formed billions of years after most meteorites formed. B) Most Earth rocks have been melted and reformed since Earth formed from the solar nebula. C) Meteorites formed before the solar nebula began to condense. D) Most meteorites come from other planetary systems that formed before our solar system.
Answer: B
1) Compared to the distance between Earth and Mars, the distance between Jupiter and Saturn is ________. A) much larger B) about the same C) much smaller D) just slightly less
Answer: A
10) The planet with a density most similar to Earth is A) Mercury. B) Venus. C) Jupiter. D) Mars. E) Uranus.
Answer: A
10) Which moons are sometimes called the Galilean moons? A) the four largest moons of Jupiter: Io, Europa, Ganymede, and Callisto B) the two largest moons in the solar system: Ganymede and Titan C) the moons that orbit their planet "backward" compared to their planet's rotation, such as Neptune's moon Triton D) the moons orbiting Uranus, which was once named "planet Galileo"
Answer: A
10) Which of the following is not a major difference between the terrestrial and jovian planets in our solar system? A) Terrestrial planets contain large quantities of ice, and jovian planets do not. B) Terrestrial planets orbit much closer to the Sun than jovian planets. C) Terrestrial planets are higher in average density than jovian planets. D) Jovian planets have rings, and terrestrial planets do not.
Answer: A
12) Which of the following is not a characteristic of the outer planets? A) They have relatively high densities. B) They have thick atmospheres. C) They are primarily made of hydrogen, helium, and hydrogen compounds. D) Their orbits are separated by relatively large distances. E) They have rings.
Answer: A
12) Which planet (besides Earth) has been visited by the largest number of robotic spacecraft? A) Mars B) Jupiter C) Venus D) Saturn
Answer: A
13) According to our theory of solar system formation, which law best explains why the solar nebula spun faster as it shrank in size? A) the law of conservation of angular momentum B) the law of conservation of energy C) the law of universal gravitation D) Einstein's law E = mc2
Answer: A
23) What do we mean by the period of heavy bombardment in the context of the history of our solar system? A) the first few hundred million years after the planets formed, which is when most impact craters were formed B) the time before planetesimals finished accreting into planets, during which many growing planetesimals must have shattered in collisions C) the time during which heavy elements condensed into rock and metal in the solar nebula D) the period about 65 million years ago when an impact is thought to have led to the extinction of the dinosaurs
Answer: A
23) Which of the following is not evidence supporting the idea that our Moon formed as a result of a giant impact? A) The Pacific Ocean appears to be a large crater—probably the one made by the giant impact. B) Computer simulations show that the Moon could really have formed in this way. C) The Moon's average density suggests it is made of rock much more like that of the Earth's outer layers than that of the Earth as a whole. D) The Moon has a much smaller proportion of easily vaporized materials than Earth.
Answer: A
25) Suppose you start with 1 kilogram of a radioactive substance that has a half-life of 10 years. Which of the following statements will be true after 20 years pass? A) You'll have 0.25 kilogram of the radioactive substance remaining. B) All the material will have completely decayed. C) You'll have 0.75 kilogram of the radioactive substance remaining. D) You'll have 0.5 kilogram of the radioactive substance remaining.
Answer: A
26) According to modern scientific dating techniques, approximately how old is the solar system? A) 4.5 billion years B) 10,000 years C) 4.6 million years D) 14 billion years
Answer: A
26) How do scientists determine the age of the solar system? A) radiometric dating of meteorites B) radiometric dating of Moon rocks C) radiometric dating of the oldest Earth rocks D) Theoretical calculations tell us how long it has taken the planets to evolve to their present forms.
Answer: A
27) The region of our solar system between Mercury and Mars has very few asteroids, while the region between Mars and Jupiter has many asteroids. Based on what you have learned, what is the most likely explanation for the lack of asteroids between Mercury and Mars? A) There were very few planetary leftovers in this region because most of the solid material was accreted by the terrestrial planets as the planets formed. B) It was too hot for asteroids to form in this part of the solar system. C) Gravity was too weak to allow asteroids to form in this part of the solar system. D) All the asteroids that formed between Mercury and Mars later migrated to the asteroid belt between Mars and Jupiter.
Answer: A
28) Based on everything you have learned about the formation of our solar system, which of the following statements is probably not true? A) Only a tiny percentage of stars are surrounded by spinning disks of gas during their formation. B) A star system's planets generally tend to orbit their star in the same direction and approximately the same plane. C) Other solar systems will also have planets in the two basic categories of terrestrial and jovian. D) Other planetary systems will have far more numerous asteroids and comets than actual planets.
Answer: A
3) In what way is Venus most similar to Earth? A) Both planets are nearly the same size. B) Both planets have very similar atmospheres. C) Both planets have similar surface geology. D) Both planets have warm days and cool nights.
Answer: A
3) Which of the following statements about our Sun is not true? A) The Sun's diameter is about 5 times that of Earth. B) The Sun is a star. C) The Sun contains more than 99% of all the mass in our solar system. D) The Sun is made mostly of hydrogen and helium.
Answer: A
38) Every 4.5 billion years, half of the atoms in a sample of uranium-238 will undergo radioactive decay and become atoms of lead-206. Suppose you lived in another planetary system around a faraway star and found a meteorite that was originally made of uranium-238, but is now one-quarter uranium-238 and three-quarters lead-206. What would be your best estimate of that planetary system's age? A) 9 billion years B) 4.5 billion years C) 2.25 billion years D) 13.5 billion years
Answer: A
8) Which planet has the most extreme temperature difference between day and night? A) Mercury B) Venus C) Earth D) Mars E) Jupiter
Answer: A
9) Which of the following is not a major pattern of motion in the solar system? A) Nearly all comets orbit the Sun in the same direction and roughly the same plane. B) Most of the solar system's large moons orbit in their planet's equatorial plane. C) The Sun and most of the planets rotate in the same direction in which the planets orbit the Sun. D) All of the planets orbit the Sun in the same direction—counterclockwise as viewed from above Earth's north pole.
Answer: A
Which of the following lists the planets of our solar system in the correct order from closest to farthest from the Sun? A) Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune B) Mercury, Earth, Venus, Mars, Jupiter, Saturn, Neptune, Uranus C) Mercury, Venus, Mars, Earth, Saturn, Jupiter, Neptune, Uranus D) Earth, Mars, Mercury, Venus, Jupiter, Saturn, Uranus, Neptune
Answer: A
13) On average, a cupful of which planet would weigh the least? A) Jupiter B) Saturn C) Uranus D) Neptune E) Mars
Answer: B
17) In what part of the solar system is Pluto found? A) the asteroid belt B) the Kuiper belt C) the Oort cloud D) the terrestrial planet region
Answer: B
19) Suppose the Sun had been born with less mass, making it a small, cooler star only able to heat everything around it to a level one-half as hot as its current temperature. According to the solar nebular theory, how would the formation of the solar system have been different? A) Asteroids would have formed farther from the Sun. B) Both terrestrial and jovian planets would have generally formed closer to the Sun. C) There would be no comets. D) There would be no terrestrial planet systems.
Answer: B
19) Why did the solar nebula heat up as it collapsed? A) Nuclear fusion occurring in the core of the protosun produced energy that heated the nebula. B) As the cloud shrank, its gravitational potential energy was converted to thermal energy. C) Radiation from other nearby stars that had formed earlier heated the nebula. D) The shock wave from a nearby supernova heated the gas. E) As the cloud shrank, its kinetic energy was converted to gravitational potential energy.
Answer: B
21) According to our theory of solar system formation, why do all the planets orbit the Sun in the same direction and in nearly the same plane? A) The original solar nebula happened to be disk-shaped. B) Any planets that once orbited in the opposite direction or a different plane were ejected from the solar system. C) The laws of conservation of energy and conservation of angular momentum ensure that any rotating, collapsing cloud will end up as a spinning disk. D) The Sun formed first, and as it grew in size it spread into a disk, rather like the way a ball of dough can be flattened into a pizza by spinning it. E) We would expect that a very small fraction of all planetary systems would have planets orbiting in such a pattern, so ours turned out that way due to random chance.
Answer: C
24) What percentage of the mass of the solar nebula consisted of elements other than hydrogen and helium? A) 0 percent B) 0.1 percent C) 2 percent D) 20 percent E) 80 percent
Answer: C
25) If the freezing point of all ices was at a much lower temperature, what change would that imply for the formation of our solar system? A) The gas giants could have formed closer to the sun. B) There would be no change in where gas giants could form, because the freezing point of ices did not affect the formation of gas giants. C) The gas giants would have to form at a larger distance from the sun. D) The gas giants could not have formed at all.
Answer: C
3) Which planet has the highest average surface temperature, and why? A) Mercury, because it is closest to the Sun B) Earth, because of its greenhouse effect C) Venus, because of its dense carbon dioxide atmosphere D) Mars, because of its red color E) Jupiter, because it is so big
Answer: C
32) The heavy bombardment phase of the solar system lasted A) a few million years. B) tens of millions of years. C) a few hundred million years. D) about a billion years. E) to the present time.
Answer: C
34) Which of the following does the solar nebular theory not predict? A) planets orbit the Sun in nearly circular orbits in a flattened disk B) the compositional differences between the terrestrial and jovian planets C) the equal number of terrestrial and jovian planets D) the presence of asteroids and comets E) planets orbit the Sun in the same direction
Answer: C
35) The age of the solar system can be established by radiometric dating of A) the oldest rocks on Earth. B) the oldest rocks on the Moon. C) the oldest meteorites. D) the atmosphere of Mars. E) It hasn't been done yet, but the age of the solar system could be obtained from a sample of Io's surface.
Answer: C
37) Suppose you find a rock that contains some potassium-40 (half-life of 1.25 billion years). You measure the amount and determine that there are 5 grams of potassium-40 in the rock. By measuring the amount of its decay product (argon-40) present in the rock, you realize that there must have been 40 grams of potassium-40 when the rock solidified. How old is the rock? A) 1.25 billion years B) 2.5 billion years C) 3.75 billion years D) 5 billion years E) none of the above
Answer: C
5) Which of the following observations indicates that Mars had a warmer, thicker atmosphere in the past? A) Mars lacks atmospheric ozone. B) There is a very deep and long canyon that extends across Mars. C) There are dried-up riverbeds on Mars. D) Mars has polar caps made of "dry ice." E) Mars has two small moons.
Answer: C
9) Which is the densest planet in the solar system? A) Mercury B) Venus C) Earth D) Mars E) Jupiter
Answer: C
1) How does the Sun's mass compare with that of the planets? A) It is about a hundred times more massive than Earth. B) It is about a thousand times more massive than Earth. C) It is about a hundred times more massive than all the planets combined. D) It is about a thousand times more massive than all the planets combined. E) It is about as massive as all the planets combined.
Answer: D
11) Which of the following is not a characteristic of the inner planets? A) They are smaller than the outer planets. B) They have solid, rocky surfaces. C) Their orbits are relatively closely spaced. D) They have substantial atmospheres. E) They have relatively high densities.
Answer: D
12) About 2% of our solar nebula consisted of elements heavier than hydrogen and helium. However, the very first generation of stars in the universe probably consisted only of hydrogen and helium. Which of the following statements is most likely to have been true about these first- generation stars? A) They likely had numerous terrestrial planets but no jovian planets. B) The nebula in which they formed likely had more hydrogen compounds than the nebula that formed the solar system. C) They likely had even numbers of terrestrial and jovian planets, like our solar system. D) Planets were likely very rare or non-existent around these first-generation stars.
Answer: D
14) Which of the following is the only characteristic Pluto shares with the outer planets? A) It is smaller than Earth. B) It is made mostly of ices and rock. C) Its rotation period is more than one Earth day. D) It has multiple moons. E) It doesn't have a ring system.
Answer: D
20) Why did the solar nebula flatten into a disk? A) The interstellar cloud from which the solar nebula formed was originally somewhat flat. B) The force of gravity pulled the material downward into a flat disk. C) As the nebula cooled, the gas and dust settled onto a disk. D) It flattened as a natural consequence of collisions between particles in the nebula, changing random motions into more orderly ones.
Answer: D
23) What percentage of the solar nebula's mass consisted of hydrogen and helium gases? A) 0.5 percent B) 5 percent C) 50 percent D) 98 percent E) 100 percent
Answer: D
27) What is the origin of the large moons orbiting in the equatorial planes of the jovian planets? A) They are captured asteroids. B) They are captured comets. C) They are captured planets. D) They were formed by condensation and accretion in a disk of gas around the planet. E) They were formed by giant impacts.
Answer: D
29) Which of the following are relatively unchanged fragments from the early period of planet building in the solar system? A) asteroids B) Kuiper belt comets C) Oort cloud comets D) all of the above
Answer: D
