Exam
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1)
How do scientists estimate how old the solar system is?
1)
A)
They measure the abundances of radioactive elements in meteorites, and use their half–lives
to calculate the age.
B)
They measure how fast the Sun is losing energy, and how much energy it has to lose.
C)
They make a guess: no one really knows how old the solar system is.
D)
They look up the answer in a book.
E)
They measure the speeds and distances of galaxies, and calculate the time it took for them to
travel that distance.
2)
In essence, the nebular theory holds that ________.
2)
A)
nebulae are clouds of gas and dust in space
B)
the planets each formed from the collapse of its own separate nebula
C)
The nebular theory is a discarded idea that imagined planets forming as a result of a
near–collision between our Sun and another star.
D)
our solar system formed from the collapse of an interstellar cloud of gas and dust
3)
The heavy bombardment phase of the solar system lasted
3)
A)
to the present time.
B)
several million years.
C)
several hundreds of millions of years.
D)
several tens of millions of years.
E)
about a billion years.
4)
How is Einstein’s famous equation, E =mc2, important in understanding the Sun?
4)
A)
The Sun generates energy to shine by losing 4 million tons of mass each second.
B)
The Sun has a magnetic field strong enough to influence the atmospheres of the planets.
C)
The Sun’s surface temperature is about 6,000° Celsius.
D)
The Sun is extremely massive.
5)
Which planet has a ring system?
5)
A)
Uranus
B)
Saturn
C)
Neptune
D)
Jupiter
E)
All of the above
6)
Which of the following statements best explains why the planets orbit in nearly a single plane and
in the same direction around the Sun?
6)
A)
The Sun rotates in the same direction, and spun out the planets as it formed.
B)
The planets all rotate in same direction as they orbit.
C)
The planets formed from a disk of rotating gas.
D)
It’s a mysterious coincidence: the planets form randomly, so it’s a puzzle how they orbit that
way.
7)
Suppose that the temperature of the solar nebula had been much colder. How might the Solar
System look different today?
7)
A)
The gas giant planets might be bigger and farther from the Sun.
B)
Terrestrial planets may have formed at a larger distance from the Sun.
C)
More planets would have formed.
D)
The gas giant planets might be bigger and closer to the Sun.
8)
A rock sample from the moon includes a mineral that contains small amounts of the radioactive
isotope Potassium–40 and its daughter element Argon–40 (half–life of 1.3 billion years). This
mineral would not form with any Argon–40. Consider a crystal with 7 atoms of Argon–40 for every
1 atom of Potassium–40. How many half–lives has this sample existed?
8)
A)
1
B)
2
C)
3
D)
4
9)
Based on our current theory of Earth’s formation, the water we drink comes from
9)
A)
chemical reactions that occurred in Earth’s crust after Earth formed.
B)
material left behind during the giant impact that formed the Moon.
C)
ice that condensed in the solar nebula in the region where Earth formed.
D)
comets that impacted Earth.
E)
chemical reactions that occurred in Earth’s core after Earth formed.
10)
Which of the following puzzles in the solar system cannot be explained by a giant impact event?
10)
A)
the formation of the Moon
B)
the extreme axis tilt of Uranus
C)
the large metallic core of Mercury
D)
the backward rotation of Venus
E)
the orbit of Triton in the opposite direction to Neptune’s rotation
11)
According to our theory of solar system formation, what are asteroids and comets?
11)
A)
chunks of rock or ice that condensed after the planets and moons finished forming
B)
chunks of rock or ice that were expelled from planets by volcanoes
C)
leftover planetesimals that never accreted into planets
D)
the shattered remains of collisions between planets
12)
What are the main constituents of the jovian planets?
12)
A)
hydrogen and helium
B)
rocky minerals and water, as on Earth
C)
nitrogen and methane
D)
ammonia and water
E)
ammonia and methane
13)
If a radioactive isotope were injected into your bloodstream, how many half–lives would you have
to wait before the amount of this isotope in your body is 1
16 its original amount?
13)
A)
1
B)
2
C)
3
D)
4
E)
5
14)
Where are most of the known asteroids found?
14)
A)
between the orbits of the jovian planets
B)
between the orbits of the terrestrial planets
C)
between the orbits of Mars and Jupiter
D)
in the Oort cloud
E)
in the Kuiper belt
15)
Which of the following observations indicates that conditions on Mars may have been suitable for
life in the past?
15)
A)
There are very large extinct volcanoes on Mars.
B)
Mars has polar caps made of “dry ice.”
C)
There are dried–up riverbeds on Mars.
D)
There is a very deep and long canyon that extends across Mars.
E)
Mars has two small moons.
16)
Based on everything you have learned about the formation of our solar system, which of the
following statements is probably not true?
16)
A)
A star system’s planets generally tend to orbit their star in the same direction and
approximately the same plane.
B)
Only a tiny percentage of stars are surrounded by spinning disks of gas during their
formation.
C)
Other planetary systems will have far more numerous asteroids and comets than actual
planets.
D)
Other solar systems will also have planets in the two basic categories of terrestrial and jovian.
17)
Observations vs. Explanations. Which of the following statements is an explanation?
17)
A)
All planets orbit the Sun in the same direction and nearly the same plane.
B)
Hydrogen and helium are important constituents of stars.
C)
The inner planets of the solar system are rocky and the outer planets are gas giants.
D)
The farther a galaxy is, the faster it is moving away from us.
E)
The orderly orbits of planets arose from their formation in a rotating cloud of gas.
E
18)
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?
18)
A)
You’ll have 0.5 kilogram of the radioactive substance remaining.
B)
All the material will have completely decayed.
C)
You’ll have 0.25 kilogram of the radioactive substance remaining.
D)
You’ll have 0.75 kilogram of the radioactive substance remaining.
C
19)
Which planet has the highest average surface temperature, and why?
19)
A)
Mercury, because of its dense carbon dioxide atmosphere
B)
Venus, because of its dense carbon dioxide atmosphere
C)
Jupiter, because it is so big
D)
Mercury, because it is closest to the Sun
E)
Mars, because of its red color
B
B
20)
What do meteorites reveal about the solar system?
20)
A)
Nothing, because they come from other star systems.
B)
They reveal that the age of the solar system is approximately 4.6 billion years.
C)
They reveal that the early solar system consisted mostly of hydrogen and helium gas.
D)
They reveal that meteorites are much older than the comets and planets.
E)
They reveal that the solar system once contained 10 planets.
21)
Compared to the distance between Earth and Mars, the distance between Jupiter and Saturn is
________.
21)
A)
about the same
B)
much larger
C)
much smaller
D)
just slightly less
22)
A rock sample from the moon includes a mineral that contains small amounts of the radioactive
isotope Potassium–40 and its daughter element Argon–40 (half–life of 1.3 billion years). This
mineral would not form with any Argon–40. Consider a crystal with 7 atoms of Argon–40 for every
1 atom of Potassium–40. How many atoms of Potassium–40 were present when the crystal formed
for each atom of Potassium–40 that exists today?
22)
A)
1
B)
7
C)
8
D)
None
23)
The nebular theory of the formation of the solar system successfully predicts all but one of the
following. Which one does the theory not predict?
23)
A)
Planets orbit around the Sun in nearly circular orbits in a flattened disk.
B)
the presence of asteroids and comets
C)
the compositional differences between the terrestrial and jovian planets
D)
the craters on the Moon
E)
the equal number of terrestrial and jovian planets
24)
What percentage of the solar nebula’s mass consisted of hydrogen and helium gases?
24)
A)
100 percent
B)
98 percent
C)
50 percent
D)
5 percent
E)
0.5 percent
25)
According to our basic scenario of solar system formation, why do the jovian planets have
numerous large moons?
25)
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)
The many moons of the jovian planets remains one of the unexplained mysteries of the
formation of our solar system.
C)
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.
D)
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.
26)
Suppose you view the solar system from high above Earth’s North Pole. Which of the following
statements about planetary orbits will be true?
26)
A)
The inner planets orbit the Sun clockwise while the outer planets orbit the Sun
counterclockwise.
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)
All the planets orbit counterclockwise around the Sun.
27)
A rock sample from the moon includes a mineral that contains small amounts of the radioactive
isotope Potassium–40 and its daughter element Argon–40 (half–life of 1.3 billion years). This
mineral would not form with any Argon–40. Consider a crystal with 7 atoms of Argon–40 for every
1 atom of Potassium–40. How long ago did this crystal form?
27)
A)
1.3 billion years ago
B)
5.2 billion years ago
C)
13.5 billion years ago
D)
3.9 billion years ago
28)
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?
28)
A)
the law of conservation of energy
B)
the two laws of thermal radiation
C)
Newton’s third law
D)
the law of conservation of angular momentum
29)
You are measuring how velocity changes with time of two stars like the Sun in order to detect their
planets. Both stars have a velocity curve with a periods of 2 years, but the maximum size
(peak–to–peak amplitude) of the velocity curve of star A is 100 km/s, and for star B it is 200 km/s.
What causes this difference? Assume the planets are named after their stars.
29)
A)
Planet A is farther from Star A than Planet B is from Star B.
B)
Planet A is more massive than Planet B.
C)
Planet A is closer to Star A than Planet B is to Star B.
D)
Planet A is less massive than Planet B.
E)
Not possible to say, since you’re measuring the velocity curve of the stars, not the planets.
30)
Which of the following statements about the accelerations and gravitational forces between a planet
and a star is true?
30)
A)
Forces are equal and opposite; the planet is accelerated more than the star.
B)
Forces are equal and opposite; the star is accelerated more than the planet.
C)
Accelerations and forces are both equal and opposite.
D)
Acceleration is equal and opposite; the star feels more force more than the planet.
E)
Acceleration is equal and opposite; the planet feels more force more than the star.
31)
Where did the elements heavier than hydrogen and helium come from?
31)
A)
They were produced in the Big Bang.
B)
They were produced inside stars.
C)
They were produced inside dense interstellar gas.
D)
They evolved from hydrogen and helium shortly after the Big Bang.
E)
All of the above
B
32)
The jovian planets in our solar system are ________.
32)
A)
Pluto and Eris
B)
Jupiter, Saturn, Uranus, and Neptune
C)
Mercury, Venus, Earth, and Mars
D)
Io, Europa, Ganymede, and Callisto
B
33)
Why are terrestrial planets denser than jovian planets?
33)
A)
Actually, the jovian planets are denser than the terrestrial planets.
B)
The Sun’s gravity gathered dense materials into the inner solar system.
C)
Gravity compresses terrestrial planets to a higher degree, making them denser.
D)
Only dense materials could condense in the inner solar nebula.
D
A
34)
If the proto star that became our Sun had been hotter and more luminous when it formed, what
changes (if any) might have been experienced by our Solar System?
34)
A)
No comets could have formed.
B)
Jupiter would now be farther from the Sun.
C)
Mars would be a gas giant.
D)
Terrestrial planes could only have formed closer to the Sun.
E)
The Moon would not exist.
35)
Which jovian planet does not have rings?
35)
A)
All the jovian planets have rings.
B)
Jupiter
C)
Mars
D)
Uranus
E)
Neptune
A
36)
Which of the following statements does not apply to the formation of gas giants like Jupiter,
compared to terrestrial planets?
36)
A)
formed in a region with lower orbital speeds
B)
formed in regions cold enough for water to freeze
C)
accreted from icy planetesimals
D)
caused icy planetesimals to slingshot away from the Sun, to become Oort cloud comets
E)
surface dramatically altered during bombardment
E
37)
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?
37)
A)
It was fairly flat to begin with, and retained this flat shape as it collapsed.
B)
It flattened as a natural consequence of collisions between particles in the nebula.
C)
The law of conservation of energy
D)
The force of gravity pulled the material downward into a flat disk.
B
B
38)
Pluto is different from the other outer planets in all of the following ways except which one?
38)
A)
It doesn’t have rings.
B)
It is made mostly of ices.
C)
Its surface temperature is very cold.
D)
Its orbit is not very close to being circular.
E)
It has only one moon.
39)
According to our theory of solar system formation, why do we find some exceptions to the general
rules and patterns of the planets?
39)
A)
Our theory is not quite correct because it cannot explain these exceptions.
B)
The exceptions probably represent objects that were captured by our solar system from
interstellar space.
C)
The exceptions exist because, even though our theory is as correct as possible, nature never
follows rules precisely.
D)
The exceptions probably represent objects that formed recently, rather than early in the
history of the solar system.
E)
Most of the exceptions are the result of giant impacts or close gravitational encounters.
40)
Which planet (besides Earth) has been visited by the largest number of robotic spacecraft?
40)
A)
Saturn
B)
Jupiter
C)
Mars
D)
Venus
41)
Which of the following is not a major difference between the terrestrial and jovian planets in our
solar system?
41)
A)
Terrestrial planets contain large quantities of ice, and jovian planets do not.
B)
Jovian planets have rings, and terrestrial planets do not.
C)
Terrestrial planets orbit much closer to the Sun than jovian planets.
D)
Terrestrial planets are higher in average density than jovian planets.
42)
Imagine a planet like Earth orbiting the Sun, at an average distance of 1 AU but with a highly
eccentric orbit. Which of the following statements about this orbit is not true?
42)
A)
The seasons are very extreme.
B)
The planet does not maintain a constant speed around the Sun.
C)
The planet is sometimes very close to the Sun, and sometimes very far.
D)
The period is longer than a year.
43)
According to our theory of solar system formation, what three major changes occurred in the solar
nebula as it shrank in size?
43)
A)
It got hotter, its rate of rotation increased, and it flattened into a disk.
B)
It gained energy, it gained angular momentum, and it flattened into a disk.
C)
Its mass, temperature, and density all increased.
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.
44)
Which of the following is the origin of almost all the large moons around the jovian planets?
44)
A)
They are captured comets.
B)
They were formed by condensation and accretion in a disk of gas around the planet.
C)
They are captured planets.
D)
They were formed by giant impacts.
E)
They are captured asteroids.
45)
The following statements are all true. Which one counts as an “exception to the rule” in being
unusual for our solar system?
45)
A)
The diameter of Earth’s Moon is about 1/4 that of Earth.
B)
Jupiter has a very small axis tilt.
C)
Saturn has no solid surface.
D)
Venus does not have a moon.
46)
What do we mean by the period of heavy bombardment in the context of the history of our solar
system?
46)
A)
the period about 65 million years ago when an impact is thought to have led to the extinction
of the dinosaurs
B)
the time before planetesimals finished accreting into planets, during which many growing
planetesimals must have shattered in collisions
C)
the first few hundred million years after the planets formed, which is when most impact
craters were formed
D)
the time during which heavy elements condensed into rock and metal in the solar nebula
47)
Which planet, other than Earth, has visible water ice on it?
47)
A)
the Moon
B)
Jupiter
C)
Mercury
D)
Venus
E)
Mars
Answer:
48)
The Cassini mission to Saturn consists of ________.
48)
A)
an orbiter that orbits Saturn and a probe that descended to the surface of Titan
B)
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
C)
an orbiter that orbits Saturn and a probe that descended into Saturn’s atmosphere
D)
a large spacecraft that flew by Saturn on its way to other planets
Answer:
49)
Why did the solar nebula flatten into a disk?
49)
A)
The force of gravity pulled the material downward into a flat disk.
B)
The interstellar cloud from which the solar nebula formed was originally somewhat flat.
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:
Answer:
50)
The planet in our solar system with the highest average surface temperature is ________.
50)
A)
Neptune
B)
Mercury
C)
Venus
D)
Earth
51)
Which planet listed below has the most extreme seasons?
51)
A)
Uranus
B)
Jupiter
C)
Mars
D)
Earth
52)
About 2% of our solar nebula consisted of elements besides hydrogen and helium. However, the
very first generation of star systems 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 star systems?
52)
A)
Jovian planets in these first–generation star systems had clouds made of water and other
hydrogen compounds.
B)
These first–generation star systems typically had several terrestrial planets in addition to
jovian planets.
C)
Like the jovian planets in our solar system, the jovian planets in these first–generation
systems were orbited by rings.
D)
There were no comets or asteroids in these first–generation star systems.
53)
Which of the following statements about our Sun is not true?
53)
A)
The Sun is made mostly of hydrogen and helium.
B)
The Sun’s diameter is about 5 times that of Earth.
C)
The Sun contains more than 99% of all the mass in our solar system.
D)
The Sun is a star.
54)
When we say that jovian planets contain significant amounts of hydrogen compounds, we mean all
the following chemicals except ________.
54)
A)
ammonia
B)
methane
C)
water
D)
carbon dioxide
55)
Where does nuclear fusion occur in the Sun?
55)
A)
in its core
B)
just above the visible surface
C)
on the surface
D)
anywhere below the surface
E)
all of the above
56)
Which of the following types of material can condense into what we call ice at low temperatures?
56)
A)
metal
B)
hydrogen and helium
C)
rock
D)
hydrogen compounds
57)
Mars has two moons that are most similar in character to ________.
57)
A)
comets
B)
Earth’s Moon
C)
particles in the rings of Saturn
D)
small asteroids
58)
According to our theory of solar system formation, which law best explains why the solar nebula
spun faster as it shrank in size?
58)
A)
the law of conservation of energy
B)
the law of universal gravitation
C)
Einstein’s law E =mc2
D)
the law of conservation of angular momentum
59)
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?
59)
A)
The meteorites’ appearance and composition is just what we’d expect if metal and rock
condensed and accreted as our theory suggests.
B)
Their overall composition is just what we believe the composition of the solar nebula to have
been: mostly hydrogen and helium.
C)
The meteorites’ sizes are just what we’d expect if metal and rock condensed and accreted as
our theory suggests.
D)
Their appearance and composition matches what we observe in comets today, suggesting that
they were once pieces of icy planetesimals.
60)
Which of the following is not a characteristic of the inner planets?
60)
A)
Their orbits are relatively closely spaced.
B)
They are relatively smaller than the outer planets.
C)
They all have solid, rocky surfaces.
D)
They have very few, if any, satellites.
E)
They all have substantial atmospheres.
E
61)
Which of the following is not a characteristic of the outer planets?
61)
A)
Their orbits are separated by relatively large distances.
B)
They are primarily made of hydrogen and helium.
C)
They all have large quantities of gas.
D)
They have very few, if any, satellites.
E)
They all have rings.
D
A
62)
Observations of young stars (as well as theory) tell us that when the Sun was young, the solar wind
62)
A)
was weaker than it is today.
B)
was stronger than it is today.
C)
blew outward only along the Sun’s poles.
D)
was nonexistent.
E)
was about the same strength as it is today.
63)
Which of the following are relatively unchanged fragments from the early period of planet building
in the solar system?
63)
A)
asteroids
B)
Oort cloud comets
C)
Kuiper belt comets
D)
all of the above
64)
According to modern scientific dating techniques, approximately how old is the solar system?
64)
A)
14 billion years
B)
4.6 million years
C)
10,000 years
D)
4.5 billion years
65)
According to our present theory of solar system formation, how did Earth end up with enough
water to make oceans?
65)
A)
Earth formed at a distance from the Sun at which liquid water happened to be plentiful in the
solar nebula.
B)
The water was brought to the forming Earth by planetesimals that accreted near Earth’s orbit.
C)
The water was brought to the forming Earth by planetesimals that accreted beyond the orbit
of Mars.
D)
The water was formed by chemical reactions among the minerals in the Earth’s core.
66)
What is the giant impact hypothesis for the origin of the Moon?
66)
A)
The Moon formed when two gigantic asteroids collided with one another.
B)
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.
C)
The Moon formed just like the Earth, from accretion in the solar nebula.
D)
The Moon formed from material blasted out of the Earth’s mantle and crust by the impact of a
Mars–size object.
67)
What is the primary basis upon which we divide the ingredients of the solar nebula into four
categories (hydrogen/helium; hydrogen compound; rock; metal)?
67)
A)
the atomic mass numbers of various materials
B)
the locations of various materials in the solar nebula
C)
the temperatures at which various materials will condense from gaseous form to solid form
D)
the amounts of energy required to ionize various materials
C
68)
Suppose you find a rock that contains some potassium–40 (half–life of 1.3 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?
68)
A)
2.6 billion years
B)
3.9 billion years
C)
1.3 billion years
D)
5.2 billion years
E)
none of the above
B
69)
In what way is Venus most similar to Earth?
69)
A)
Both planets are nearly the same size.
B)
Both planets have warm days and cool nights.
C)
Both planets have similar surface geology.
D)
Both planets have very similar atmospheres.
A
D
70)
Which of the following is not an exception to the general patterns of motion in the solar system?
70)
A)
the rings of Saturn
B)
the “backward” orbit of Triton around Neptune
C)
the extreme axis tilt of Uranus
D)
the counterclockwise rotation of Venus
E)
the large size of Earth’s moon
71)
What percentage of the solar nebula‘s mass consisted of rocky material?
71)
A)
80 percent
B)
0 percent
C)
2 percent
D)
20 percent
E)
0.4 percent
72)
The terrestrial planets are made almost entirely of elements heavier than hydrogen and helium.
According to modern science, where did these elements come from?
72)
A)
They were produced by gravity in the solar nebula as it collapsed.
B)
They have been present in the universe since its birth.
C)
They were produced by stars that lived and died before our solar system was born.
D)
They were made by chemical reactions in interstellar gas.
73)
Why did the solar nebula heat up as it collapsed?
73)
A)
Radiation from other nearby stars that had formed earlier heated the nebula.
B)
Collisions among planetesimals generated friction and heat.
C)
As the cloud shrank, its gravitational potential energy was converted to thermal energy.
D)
Nuclear fusion occurring in the core of the protosun produced energy that heated the nebula.
E)
The shock wave from a nearby supernova heated the gas.
74)
What do we mean by accretion in the context of planet formation?
74)
A)
the growth of the Sun as the density of gas increased in the center of the solar nebula
B)
the growth of planetesimals from smaller solid particles that collided and stuck together
C)
the formation of moons around planets
D)
the solidification of ices, rocks, and metal from the gas of the solar nebular
75)
How do scientists determine the age of the solar system?
75)
A)
radiometric dating of meteorites
B)
radiometric dating of the oldest Earth rocks
C)
radiometric dating of Moon rocks
D)
Theoretical calculations tell us how long it has taken the planets to evolve to their present
forms.
Answer:
76)
How does the Sun‘s mass compare with that of the planets?
76)
A)
It is about as massive as all the planets combined.
B)
It is a hundred times more massive than all the planets combined.
C)
It is a thousand times more massive than Earth.
D)
It is a thousand times more massive than all the planets combined.
E)
It is a hundred times more massive than Earth.
Answer:
77)
Which is the densest planet in the solar system?
77)
A)
Earth
B)
Mars
C)
Venus
D)
Jupiter
E)
Mercury
Answer:
Answer:
78)
Which moons are sometimes called the Galilean moons?
78)
A)
the four largest moons of Jupiter: Io, Europa, Ganymede, and Callisto
B)
the moons orbiting Uranus, which was once named “planet Galileo”
C)
the two largest moons in the solar system: Ganymede and Titan
D)
the moons that orbit their planet “backward” compared to their planet’s rotation, such as
Neptune’s moon Triton
79)
Which planet could an astronaut visit without the need for a spacesuit (and survive)?
79)
A)
Mars
B)
Mercury
C)
the Moon
D)
Venus
E)
None; an astronaut would need a spacesuit to survive a visit to any other planet in the solar
system.
80)
The age of the solar system can be established by radioactive dating of
80)
A)
the atmosphere of Mars.
B)
the oldest meteorites.
C)
the oldest rocks on the Moon.
D)
the oldest rocks on Earth.
E)
It hasn’t been done yet, but the age of the solar system could be obtained from a sample of Io’s
surface.
81)
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?
81)
A)
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
B)
because only the outer planets captured hydrogen and helium gas from the solar nebula
C)
because only metal and rock could condense in the inner solar system, while ice also
condensed in the outer solar system
D)
because the Sun’s gravity was stronger in the outer solar system, allowing more solid material
to collect
82)
Which of the following is furthest from the Sun?
82)
A)
an asteroid in the asteroid belt
B)
Pluto
C)
a comet in the Oort cloud
D)
a comet in the Kuiper belt
E)
Neptune
C
83)
Imagine that an alien spaceship crashed onto Earth. Which statement would most likely be true?
83)
A)
The crash would create a noticeable crater.
B)
It would crash in the ocean.
C)
All the evidence of the crash would be quickly whisked off by the U.S. military to Area 51 in
Nevada.
D)
The aliens‘ home world is another planet in our own solar system.
B
84)
According to modern science, what was the approximate chemical composition of the solar nebula?
84)
A)
roughly equal proportions of hydrogen, helium, water, and methane
B)
50% hydrogen and helium, 50% everything else
C)
98% hydrogen, 2% helium
D)
98% hydrogen and helium, 2% everything else
D
C
85)
Which of the following lists the ingredients of the solar nebula from highest to lowest percentage of
mass of the nebula?
85)
A)
light gases (H, He), hydrogen compounds (H2O, CH4, NH3), metals, rocks
B)
hydrogen compounds (H2O, CH4, NH3), rocks, metals, light gases (H, He)
C)
light gases (H, He), hydrogen compounds (H2O, CH4, NH3), rocks, metals
D)
hydrogen compounds (H2O, CH4, NH3), light gases (H, He), rocks, metals
E)
hydrogen compounds (H2O, CH4, NH3), light gases (H, He), metals, rocks
86)
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?
86)
A)
hydrogen compounds; hydrogen and helium gas; metal; rock
B)
hydrogen, water, methane, helium
C)
hydrogen and helium gas; rock; metal; hydrogen compounds
D)
hydrogen and helium gas; hydrogen compounds; rock; metal
87)
Which of the following is not true of Mercury?
87)
A)
Its surface is heavily cratered.
B)
It has been studied closely by several NASA spacecraft.
C)
At any given time, about half the planet is colder than Antarctica.
D)
Mercury has essentially no atmosphere.
88)
Which of the following discoveries would cause us to re–evaluate the nebular theory for forming
planets?
88)
A)
Of the star’s five terrestrial planets, one has a large moon.
B)
A star’s 5 terrestrial planets orbit in the opposite direction of its 3 jovian planets.
C)
A star has zero planets.
D)
A star has 20 planets.
E)
Two of the star’s planets are rotating in directions backwards compared to their orbital
direction.
89)
If a radioactive isotope that was injected into your bloodstream has a half–life of 5 hours, how
many hours do you have to wait before the amount of this isotope in your body is 1
16 its original
amount?
89)
A)
25
B)
5
C)
15
D)
10
E)
20
90)
The terrestrial planets in our solar system are ________.
90)
A)
Jupiter, Saturn, Uranus, and Neptune
B)
Mercury, Venus, Earth, and Mars
C)
Pluto and Eris
D)
Mars, Jupiter, Saturn, Uranus, and Neptune
91)
Which of the following is not a major pattern of motion in the solar system?
91)
A)
The Sun and most of the planets rotate in the same direction in which the planets orbit the
Sun.
B)
Most of the solar system’s large moons orbit in their planet’s equatorial plane.
C)
Nearly all comets orbit the Sun in same direction and roughly the same plane.
D)
All of the planets orbit the Sun in the same directioncounterclockwise as viewed from above
Earth’s north pole.
92)
What kind of material in the solar nebula could remain solid at temperatures as high as 1,500 K,
such as existed in the inner regions of the nebula?
92)
A)
molecules such as methane and ammonia
B)
hydrogen compounds
C)
metals
D)
rocks
E)
silicon–based minerals
93)
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?
93)
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)
All the asteroids that formed between Mercury and Mars later migrated to the asteroid belt
between Mars and Jupiter.
D)
Gravity was too weak to allow asteroids to form in this part of the solar system.
94)
Which of the following lists the planets of our solar system in the correct order from closest to
farthest from the Sun?
94)
A)
Mercury, Earth, Venus, Mars, Jupiter, Saturn, Neptune, Uranus
B)
Earth, Mars, Mercury, Venus, Jupiter, Saturn, Uranus, Neptune
C)
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
D)
Mercury, Venus, Mars, Earth, Saturn, Jupiter, Neptune, Uranus
95)
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?
95)
A)
The laws of conservation of energy and conservation of angular momentum ensure that any
rotating, collapsing cloud will end up as a spinning disk.
B)
Luck explains it, as we would expect that most other solar systems would not have all their
planets orbiting in such a pattern.
C)
The original solar nebula happened to be disk–shaped by chance.
D)
Any planets that once orbited in the opposite direction or a different plane were ejected from
the solar system.
E)
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.
96)
The planet closest in size to Earth is
96)
A)
the Moon.
B)
Pluto.
C)
Mars.
D)
Venus.
E)
Mercury.
97)
How do we know the mass of Neptune?
97)
A)
the orbital speed of Neptune moving around the Sun
B)
the periods and sizes of the orbits of the moons around Neptune
C)
the distance of Neptune from the Earth and its rotation period
D)
the period and size of Neptune’s orbit around the Sun
E)
the size and density of Neptune
98)
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?
98)
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)
The terrestrial planets formed inside the frost line of the solar nebula and the jovian planets
formed beyond it.
C)
Both types of planet begun 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.
D)
Swirling disks of gas, like the solar nebula in miniature, formed around the growing jovian
planets but not around the growing terrestrial planets.
99)
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?
99)
A)
3.75 billion years
B)
1.25 billion years
C)
5.0 billion years
D)
2.5 billion years
100)
What do we mean by the frost line when we discuss the formation of planets in the solar nebula?
100)
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 marks the special distance from the Sun at which hydrogen compounds become abundant;
closer to the Sun, there are no hydrogen compounds.
C)
It is the altitude in a planet’s atmosphere at which snow can form.
D)
It is another way of stating the temperature at which water freezes into ice.
101)
What percentage of the mass of the solar nebula consisted of elements other than hydrogen and
helium?
101)
A)
20 percent
B)
80 percent
C)
2 percent
D)
0 percent
E)
0.1 percent
102)
According to present understanding, which of the following statements about the solar wind is not
true?
102)
A)
It swept vast amounts of gas from the solar nebula into interstellar space.
B)
It is even stronger today than it was when the Sun was young.
C)
It helped in the transfer of angular momentum from the young Sun to particles that blew into
interstellar space, which explains why the Sun rotates so slowly today.
D)
It consists of charged particles blown off the surface of the Sun.
103)
Astronomers now classify Pluto as really just a large member of
103)
A)
the moon system around Neptune.
B)
the asteroid belt.
C)
an extrasolar planetary system.
D)
the Kuiper belt.
E)
the Oort cloud.
104)
Which of the following statements about Mars is not true?
104)
A)
It is considered part of our inner solar system.
B)
It is frozen today, but once had flowing water.
C)
We could survive on Mars without spacesuits, as long as we brought oxygen in scuba tanks.
D)
We have landed spacecraft on its surface.
105)
Which of the following statements about the recently–discovered object Eris is not true?
105)
A)
It is thought to be the first example of a new class of object.
B)
It orbits the Sun in the same direction as the other planets.
C)
It lies well beyond Pluto and Neptune.
D)
It is slightly larger than Pluto.
106)
In what way is Pluto more like a comet than a planet?
106)
A)
It sometimes enters the inner solar system.
B)
It is made mostly of rock and ice.
C)
It has a long tail. It has a moon.
107)
If the freezing point of ices of all types were at a much lower temperature, what change would that
imply for the formation of our solar system?
107)
A)
The gas giants would have to form at a larger distance.
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 could have formed at a closer distance.
108)
Which of the following is not evidence supporting the idea that our Moon formed as a result of a
giant impact?
108)
A)
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.
B)
The Moon has a much smaller proportion of easily vaporized materials than Earth.
C)
Computer simulations show that the Moon could really have formed in this way.
D)
The Pacific Ocean appears to be a large craterprobably the one made by the giant impact.
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
109)
How would the solar system be different today if the entire planet forming disk had been
warmer than 300K? Why?
109)
110)
Briefly summarize the differences between terrestrial and jovian planets.
110)
111)
Briefly describe the modern theory of how our Moon formed.
111)
112)
If we were to re–run the formation of the solar system, what would likely be the same and
what would likely be different?
112)
113)
Suppose the entire solar nebula had cooled to a very low temperature before the solar
wind cleared it away. Do you think Earth would be the same? Why or why not?
113)
114)
Describe the ways in which Pluto is different from the terrestrial and jovian planets in the
solar system.
114)
115)
List at least three of the notable exceptions to the general patterns of the solar system.
115)
116)
Briefly describe the two main lines of evidence for the modern theory of the moon’s
formation, wherein the Earth was hit by an approximately Mars–sized object.
116)
117)
Explain how the age of a rock can be determined by radiometric dating.
117)
118)
Suppose you discovered a meteorite that contains small amounts of potassium–40, which
has a half–life of 1.3 billion years, and its decay product argon–40. You determine that 1/16
of the original potassium–40 remains; the other 15/16 has decayed into argon–40. How old
is the meteorite? Based on your answer, where is this meteorite probably from?
118)
119)
In the 1800s, many people assumed that Venus would have tropical temperatures, but
instead it is very hot. Explain why tropical temperatures would have made sense given
what was known in the 1800s, and why Venus instead turns out to be very hot.
119)
120)
Explain why the early Earth did not form with water, and how it gained it later in its
formation.
120)
121)
Briefly summarize the observed patterns of motion in our solar system that are consistent
with the nebular theory.
121)
TRUE/FALSE. Write ‘T’ if the statement is true and ‘F’ if the statement is false.
122)
The more massive planets in the solar system tend to be less dense than the lower mass planets.
122)
123)
Outside the frost line, planetesimals could form more quickly due to the presence of both rock and
ice.
123)
124)
Within the frost line, planetesimals were composed entirely of rock, and outside the frost line,
planetesimals were composed entirely of ice.
124)
125)
The Moon probably formed at the same time that Earth formed, rather like the formation of a
double planet.
125)
126)
All the planets in the solar system have at least one moon.
126)
127)
The jovian planets have no solid surface.
127)
128)
At greater distances from the sun, planetary surface temperatures increase.
128)
129)
All four of the giant outer planetsJupiter, Saturn, Uranus, and Neptunehave rings.
129)
130)
Pluto is the largest solar system object beyond the orbit of Neptune
130)
131)
A key clue to how the solar system formed is the observation that all the planets orbit close to the
same plane.
131)
132)
Based on our theory of how our own solar system formed, we would expect that other solar
systems would be quite common.
132)
133)
Within about 4 AU, all planets are rocky.
133)
134)
All planets orbit the Sun in the same direction (counterclockwise as viewed from above Earth’s
North Pole).
134)
135)
All the planets in the solar system rotate in the same direction as they orbit the Sun.
135)
136)
Jupiter and the other gas giants formed close to the sun and migrated outward.
136)
137)
Earth’s atmosphere resulted from the impact of icy planetesimals that originated in the outer
regions of the Solar System.
137)
138)
Impacts were extremely common in the young solar system but are less common today.
138)
139)
Oceans cover more of Earth’s surface than land.
139)
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
140)
More pattern finding: Examine table 6.1 from the textbook on page 150. Identify and describe one pattern in the
data. Give specific information to support the pattern you describe.
141)
The Solar Nebula as a Scientific Theory: You are describing the solar nebula theory to a friend. You point out that it
provides an explanation for the regular motion in our solar system, the division of the planets into terrestrial
and jovian types, and an explanation for the origin and nature of comets and asteroids. Your friend agrees that
this is all very nice, but that it seems that the solar nebula theory fails the basic criteria for a scientific theory, to
make predictions about the natural world that can be observationally tested. In her opinion, all the solar nebula
theory does is explain known facts, albeit in a compelling and economical way. How would you answer your
friend and make the case that the solar nebula theory is indeed a scientific theory that has passed many
observational tests? Can you think of any predictions that the solar nebula theory has made that were confirmed
only within the last decade or so?
142)
Exceptions to a Scientific Theory? The solar nebula theory gives compelling explanations for the many regularities
of our solar system. Nevertheless, the theory also claims to be perfectly consistent with the many exceptions to
its basic predictions. This seems like a glaring contradiction in which the solar nebula theory would be
consistent with any observed fact and hence not a scientific theory at all (why not?). Provide a deeper resolution
to this apparent paradox by explaining how some of the basic exceptions in our own solar system are
incorporated into the solar nebula theory. Is it really true that the theory would be consistent with any observed
facts?
Answer Key
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Answer Key
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Answer Key
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36
Answer Key
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