Deck 12: Dwarf Planets and Small Solar System Bodies

Question 1

The "S" in "S-type" asteroid stands for

A) sapphire
B) stony.
C) sulfur.
D) high albedo ("shiny").
E) large size ("super").

Answer 1

stony.

Question 2

Where are asteroids found?

A) only between Mars and Jupiter
B) only inside Earth's orbit, halfway to the Sun
C) only in the farthest reaches of the Solar System, beyond Pluto
D) throughout the entire Solar System
E) only in orbital resonances in Jupiter's orbit

Answer 2

throughout the entire Solar System

Question 3

The mass of all the known asteroids combined is approximately equal to

A) half the mass of Earth.
B) three times the mass of Earth.
C) twice the mass of Mars.
D) the mass of Mars.
E) less than one-third the mass of the Moon.

Answer 3

less than one-third the mass of the Moon.

Question 4

The major property that differentiates a dwarf planet from a major planet is that dwarf planets

A) are not perfect spheres.
B) are composed of mostly water ice.
C) are found beyond Neptune's orbit.
D) are not the single dominant object in their orbit.
E) may not have moons.

Question 5

Pluto has an atmosphere that comes and goes over an orbital period, because

A) the atmosphere escapes into space because of the low escape velocity from Pluto.
B) the atmosphere is pulled away from the planet by interaction with its moon Charon.
C) the atmosphere "freezes out" when Pluto is at its farthest from the Sun.
D) chemical reactions between Pluto's atmosphere and gas expelled by its many volcanoes generate carbon dioxide, which is too heavy to stay aloft in the atmosphere.
E) it is replenished by comet impacts at the far point of its orbit, and dissipates at the near point due to heat from the Sun.

Question 6

Which group of asteroids regularly crosses Earth's orbit and thus might possibly collide with our planet?

A) the Amors
B) the Atens
C) the Kuiper Belt objects
D) the Trojans
E) all of these

Question 7

If we know the semimajor axis and ________ of an object's orbit, then we can determine the object's closest and farthest points from the mass it is orbiting.

A) the total mass
B) eccentricity
C) the central mass
D) average velocity
E) albedo

Question 8

Most asteroids are located between the orbits of

A) Earth and Mars.
B) Mars and Jupiter.
C) Jupiter and Saturn.
D) Neptune and Pluto.
E) the Kuiper Belt and the Oort Cloud.

Question 9

Pluto is classified as a dwarf planet because

A) it has not cleared other bodies from its orbit.
B) it is more than 1,000 times smaller than Earth's Moon.
C) it has no moons of its own.
D) it has a unique chemical composition that is very different from other planets.
E) it orbits just outside the Solar System.

Question 10

The "M" in "M-type" asteroid stands for

A) magnesium.
B) Mars-orbiting.
C) metal.
D) major.
E) medium-sized.

Question 11

Currently the surface of the dwarf planet Eris is covered with ________, which makes it have what may be the highest albedo of any object in the Solar System.

A) methane ice
B) water ice
C) nitrogen ice
D) sulfur dioxide ice
E) carbon dioxide ice

Question 12

Pluto is composed primarily of

A) rock.
B) ice.
C) a rocky core surrounded by ice.
D) metallic hydrogen.
E) gaseous hydrogen

Question 13

The Kirkwood gaps are regularly spaced gaps in the asteroid distribution.What causes the gaps to appear?

A) The pressure of the solar wind is especially strong at these locations, evacuating asteroids out of them.
B) They are regions where gravitational pull from Mars is overcome by gravitational pull from Jupiter.
C) They are regions where an object and Jupiter would regularly line up during their orbits, causing the object to resonate with Jupiter's gravity until it leaves that orbit.
D) They are regions between Jupiter and Saturn where the combined effect of both planets' gravity prevents objects from orbiting there.
E) Asteroids on orbits within the gaps would be moving too fast to be in a stable orbit.

Question 14

What group of Solar System objects does Pluto belong to?

A) the Trojan asteroids
B) the dwarf planets
C) the giant objects
D) the terrestrial planets
E) the planetesimals

Question 15

Eris, Ceres, and Haumea are examples of

A) asteroids.
B) dwarf planets.
C) meteoroids.
D) comets.
E) meteor showers.

Question 16

The size (radius) of the largest dwarf planet is

A) between the size of Earth and Saturn.
B) about the size of Earth.
C) between the size of Mars and Venus.
D) about the size of Mercury.
E) smaller than Earth's Moon.

Question 17

When combined, asteroids in the asteroid belt have a mass equivalent to

A) about 1/10 the mass of Earth's Moon.
B) about equal to the mass of Earth's Moon.
C) about 1/2 the mass of Earth's Moon.
D) about 1/25 the mass of Earth's Moon.
E) about 1/1,000 the mass of Earth's Moon.

Question 18

The majority of asteroids are

A) very large ( $\gt$ 100 km).
B) large (30-100 km).
C) medium-sized (10-30 km).
D) small (1-10 km).
E) very small ( $\lt$ 1 km).

Question 19

The majority of asteroids are primarily composed of

A) hydrogen and helium.
B) ice and dust.
C) rock.
D) iron.
E) methane.

Question 20

Why do some short-period comets have orbits within the orbit of Jupiter?

A) They were created from the asteroid belt between Mars and Jupiter.
B) They actually orbit Jupiter rather than the Sun.
C) As they traveled to the inner Solar System from the Kuiper Belt, they suffered a gravitational encounter with Jupiter, which trapped them.
D) As they traveled to the inner Solar System from the Kuiper Belt, they collided with one another and no longer had enough speed to reach the Kuiper Belt again.
E) Most comets formed in the inner Solar System, and migrated outward later.

Question 21

Suppose we discover a comet whose orbit was very highly eccentric, retrograde, had a very large tilt with respect to the ecliptic plane, and had a period of 30,000 years.Where is the most likely place of origin for this comet?

A) the Kuiper Belt
B) the Oort Cloud
C) the asteroid belt
D) the Jovian family
E) outside the Solar System

Question 22

Identify the object shown in the figure below.

A) an active comet
B) a meteor shower
C) a meteorite
D) an asteroid
E) zodiacal dust

Question 23

A planetesimal having an orbit of only 300 years would likely have come from the

A) Atens family.
B) Oort Cloud.
C) Trojan family.
D) zodiacal zone.
E) Kuiper Belt.

Question 24

Remnants of volcanic activity on the asteroid Vesta indicate that members of the asteroid belt

A) were once part of a single protoplanet that was shattered by collisions.
B) have all undergone significant chemical evolution since formation.
C) occasionally grow large enough to become differentiated and geologically active.
D) were once a part of a young Mars.
E) used to be volcanic moons orbiting other planets.

Question 25

Approximately how often does a spectacularly active, visible comet appear in Earth's sky?

A) once a year
B) once every 5 years
C) once every 10 years
D) once every 50 years
E) once every 1,000 years

Question 26

The image of asteroid Vesta, shown in the figure below, must have been taken by

A) the Hubble Space Telescope.
B) a refracting telescope.
C) a nearby spacecraft.
D) a radio telescope.
E) a landed rover.

Question 27

The one orbital characteristic that both short- and long-period comets share is

A) mostly prograde orbits.
B) orbits with completely random tilts.
C) mostly retrograde orbits.
D) orbital periods longer than any planet.
E) highly eccentric orbits.

Question 28

In November 2005, the Japanese spacecraft Hayabusa brought back a sample from which type of object for the first time?

A) comet
B) asteroid
C) moon
D) terrestrial planet
E) gas giant planet

Question 29

Comet Halley is unique because

A) it was the first comet whose return was predicted.
B) it is a member of the Jovian family but has a retrograde orbit.
C) its period is less than a human lifetime.
D) it was successfully visited by a spacecraft.
E) it was the brightest comet ever observed by humans.

Question 30

The nucleus of a comet is mostly

A) solid ice.
B) solid rock.
C) liquid water.
D) a porous mix of ice and dust.
E) frozen carbon dioxide.

Question 31

With a semimajor axis of 18 AU, Comet Halley has a period of

A) 7 years.
B) 16 years.
C) 32 years.
D) 67 years.
E) 76 years.

Question 32

Carbonaceous chondrite meteorites are fragments of which type of asteroid?

A) A-type
B) C-type
C) M-type
D) Q-type
E) S-type

Question 33

The darkest asteroids are

A) M-type.
B) S-type.
C) C-type.
D) A-type.
E) Q-type.

Question 34

Most comets originate

A) near Earth and Venus, in the early Solar System.
B) far from the planets, many thousands of astronomical units (AU) from the Sun.
C) from the region between the orbits of Jupiter and Neptune.
D) between the Sun and Mercury.
E) between the orbits of Mars and Jupiter.

Question 35

Iron meteorites are fragments of which type of asteroid?

A) A-type
B) C-type
C) M-type
D) Q-type
E) S-type

Question 36

Which type of comet is the most common?

A) short-period
B) long-period
C) S-type
D) M-Type
E) There are approximately equal numbers of short- and long-period comets.

Question 37

Most asteroids are closest in shape to

A) a potato.
B) a banana.
C) a hot dog.
D) a stick.
E) a baseball.

Question 38

Which of the following describes comets in the Oort Cloud?

A) orbit in the same disk as the planets
B) highly processed by the Sun's light
C) high temperatures
D) composed primarily of molecular hydrogen
E) long periods

Question 39

The nucleus of the typical comet is approximately ________ in size.

A) 10 km
B) 1,000 km
C) 100 m
D) 10 m
E) 1 cm

Question 40

The most straightforward way to determine the mass of an asteroid is if it has

A) a rocky composition.
B) a moon.
C) an orbit that lies between Earth and Mars.
D) carbonaceous chondrites.
E) a magnetic field.

Question 41

Identify the phenomenon shown in the figure below.

A) an active comet
B) a meteor shower
C) a meteorite
D) an asteroid
E) zodiacal dust

Question 42

European Space Agency spacecraft Rosetta orbited Comet 67P/Churyumov-Gerasimenko, finding which of the following compounds in the comet's dust?

A) glycine
B) ethanol
C) complex carbons
D) all of these
E) none of these

Question 43

When a comet is far from the Sun, which feature(s) does it have?

A) nucleus
B) coma
C) ion tail
D) dust tail
E) all of these

Question 44

Which type of meteorite is most commonly found on Earth?

A) metallic
B) stony
C) glassy
D) They are all equally common.
E) Meteorites are not found on Earth's surface.

Question 45

The meteorite in the figure below most likely originated in a(n)

A) S-type asteroid.
B) C-type asteroid.
C) M-type asteroid.
D) active comet.
E) inactive comet.

Question 46

The Perseid meteor shower will occur

A) every month.
B) every year.
C) every 4 years.
D) every 76 years.
E) every 132 years.

Question 47

Why does the dust tail separate from the ion tail?

A) The dust has no charge, so it is not affected by the solar wind.
B) Dust cannot sublimate as ice can, so it cannot form a tail as easily.
C) The dust tail forms on the leading side of the nucleus, whereas the gas tail forms on the opposite side.
D) Dust particles are more massive than ions, so their accelerations are less.
E) The dust tail has the opposite charge as the ion tail.

Question 48

Identify the object shown in the figure below.

A) a meteor
B) a chondrite meteorite
C) an achondrite meteorite
D) an iron meteorite
E) an asteroid

Question 49

The minimum size of a meteoroid that is capable of surviving its passage through Earth's atmosphere and hitting the ground is about as big as a(n)

A) car.
B) house.
C) basketball.
D) grain of sand.
E) adult human fist.

Question 50

A large meteor shower will often occur once a year because

A) Earth typically has one large volcanic eruption every year.
B) Earth's orbit passes through the Apollo asteroid belt.
C) the Sun goes through a yearly solar cycle.
D) Jupiter routinely disturbs the orbits of asteroids in the Jovian belt.
E) Earth's orbit passes through the debris left behind by a specific comet.

Question 51

The most common types of meteorites are

A) stony meteorites.
B) iron meteorites.
C) achondrite meteorites.
D) stony-iron meteorites.
E) carbonaceous chondrite meteorites.

Question 52

Meteor showers appear as if they are coming from one particular place in the sky because

A) that is the direction from which the comet is coming toward us.
B) that is the direction in which the comet is moving away from us.
C) that is the direction toward which Earth is traveling.
D) that is the direction Earth just passed.
E) our eyes can only see the meteors that are being illuminated by the Sun.

Question 53

The strength of a meteor shower (that is, the number of visible meteors per hour) strongly depends on

A) the current season at the viewer's location.
B) Earth's velocity.
C) Earth's proximity to the object that generates the debris.
D) the thickness of Earth's ozone layer.
E) the Sun's magnetic activity.

Question 54

The meteoroids in the Leonids meteor shower, which occurs every November, come from

A) dust in the star-forming Leo nebula.
B) dust heated off Comet Tempel-Tuttle.
C) debris from the collision of Comet Shoemaker-Levy 9 with Jupiter.
D) zodiacal dust.
E) dust blown off of Earth's surface.

Question 55

Most meteors originate from

A) rocky moons.
B) solar flares.
C) asteroids and comets.
D) terrestrial planets.
E) giant planets.

Question 56

The Lyrid meteor shower occurs every year on approximately April 21 because

A) the Lyrae constellation is directly overhead at midnight.
B) Earth passes through a cloud of debris left behind by Comet Thatcher.
C) Earth passes through a cloud of debris left over from the Solar System's formation.
D) Earth undergoes a periodic volcanic eruption every April.
E) the Sun is located in the Lyrae constellation at noon.

Question 57

The depth at which meteorites are found in Antarctica tells scientists

A) the type of asteroid the meteorite fragmented from.
B) the history of impacts over time.
C) the direction the meteorite originated from.
D) the original kinetic energy of the meteorite.
E) the original mass of the meteorite.

Question 58

Comet nuclei, absent their tails, are very dark because

A) they are made of water ice.
B) they have iron and nickel mixed with ice.
C) they have organic molecules mixed with ice.
D) they are covered in rock.
E) they are too cold to emit any light.

Question 59

As a comet enters the inner Solar System, its coma can grow to a large size, as large as some planets in a few cases.What causes this growth?

A) Tidal forces from the inner planets pull material off the comet.
B) The comet moves at a higher velocity near perihelion and loose material is dislodged.
C) The comet's tectonic action is triggered by the Sun's strong gravity.
D) The rotation (spin) of the comet increases near perihelion due to angular momentum conservation.
E) The Sun's radiation heats the comet, allowing materials to sublimate into a cloud.

Question 60

When a comet comes close to the Sun, its volatile ice sublimates and transforms directly from the solid to ________ phase.

A) liquid
B) crystalline
C) energized
D) gas
E) condensate

Question 61

Name three properties of the dwarf planets Pluto and Eris that are similar.

Question 62

NEOs are a concern for every person on Earth because

A) they may collide with Earth and cause serious damage.
B) they contain a large amount of human-usable energy.
C) they are the sources of meteor showers.
D) they are primarily composed of rare, valuable materials.
E) they may harbor alien life.

Question 63

Why is it difficult to determine the sizes of dwarf planets, and what can be done to get accurate measurements?

Question 64

All of the zodiacal dust in the Solar System combined is roughly equal in mass to

A) a meteoroid.
B) a comet.
C) Jupiter.
D) the Moon.
E) a terrestrial planet.

Question 65

List the names of the known dwarf planets and their approximate location in the Solar System.

Question 66

Although most meteorites have ages around 4.5 billion years, a small subset has ages around 1.3 billion years.What caused the substantial difference in age between these two populations of meteorites?

A) These meteorites just happened to form later than most meteorites.
B) Not all meteorites hit Earth in the early Solar System.We should expect to find younger meteorites as more meteors pass through the atmosphere.
C) The younger meteorites were created when a protoplanet collided with Earth, creating the Moon.The leftover fragments became meteorites.
D) These meteorites were thrown into space after an impact with Mars and afterward some happened to collide with Earth.
E) The younger ones are the result of comets repeatedly passing close to the Sun, melting their surfaces and making them appear younger.

Question 67

Why are asteroids considered to be excellent sources for studying conditions in the early Solar System, whereas planets themselves are not?

Question 68

What implication does the composition of cometary nuclei have for the creation of life?

A) They are made entirely of liquid water, which is needed by all life.
B) They hold organic compounds, evidence that the ingredients necessary for the creation of life were present in the early solar nebula.
C) Bacteria have been found in cometary nuclei, proving that life on Earth came from comets.
D) They hold oxygen, which is needed for all life.
E) Cometary impacts would have been "softer" than asteroid impacts, helping to prevent mass extinctions.

Question 69

Identify the object shown in the figure below.

A) an active comet
B) a meteor shower
C) a meteorite
D) an asteroid
E) zodiacal dust

Question 70

Consider a meteoroid with a diameter of 10 cm and a mass of 2 kg that hits Earth head-on while traveling at a speed of 25,000 m/s.How many times larger or smaller is the meteoroid's kinetic energy compared to that of a typical train whose mass is 2 * 10⁶ kg and speed is 25 m/s?

A) The meteoroid's kinetic energy is equal to that of the train.
B) The meteoroid's kinetic energy is 1,000 times less than that of the train.
C) The meteoroid's kinetic energy is 1,000 times greater than that of the train.
D) The meteoroid's kinetic energy is 10⁶ times greater than that of the train.
E) The meteoroid's kinetic energy is 10⁹ times greater than that of the train.

Question 71

List two main differences between the orbital properties of the dwarf planet Pluto and those of planets in our Solar System.

Question 72

Which group of meteorites represents the conditions in the earliest stages of the formation of the Solar System?

A) carbonaceous chondrites
B) achondrites
C) icy meteorites
D) iron meteorites
E) stony-iron meteorites

Question 73

Which of the following likely helps replenish the zodiacal dust in the vicinity of Earth the most?

A) comets
B) meteor impacts on Earth
C) Meteor impacts on the Moon
D) volcanoes on Earth
E) tornadoes on Earth

Question 74

In the early Solar System, when the Solar System had yet to be cleared of the debris out of which it formed, which type of object would have been most likely to deposit water onto Earth's surface?

A) a comet
B) an asteroid
C) a Mars-sized protoplanet
D) Both comets and asteroids appear to be sources.
E) None, because water is not a major component of any of the objects above.

Question 75

Suppose a collision between two large asteroids creates a handful of smaller asteroid fragments, some of which orbit at 2.7 AU from the Sun and some which orbit at 2.5 AU from the Sun.Based on the asteroid distribution plot shown in the figure below, which of the two smaller asteroid groups will have a stable orbit around the Sun, and why?

Question 76

Comets have highly eccentric orbits, with eccentricities of 0.95 to 0.99 being common.Suppose a certain comet has an eccentricity of 0.99.If the semimajor axis of its orbit is 2,500 AU, what will be its distance at perihelion and at aphelion? Is this most likely a Kuiper Belt object or an Oort Cloud comet? (Note: For an ellipse, a(1+ e) is the distance from one focus to the farther edge of the long axis and a(1 -e) is the distance from the same focus to the closer edge of the long axis.)

Question 77

What does the existence of M-type asteroids tell us about their origin?

Question 78

Explain the difference between C-type asteroids and S-type asteroids.

Question 79

Cratering evidence throughout the Solar System indicates that the frequency of asteroid impact is inversely proportional to the cube of the diameter of the asteroid (that is, 1/D³).The 2013 Chelyabinsk meteor was around 20 meters in diameter and impacts of this size are expected once every 60 years, on average.If the Tunguska impact was a meteor around 100 meters in diameter, what is the expected average time between impacts of that size?

A) 1 every 220,000 years
B) 1 every 7,500 years
C) 1 every 1,200 years
D) 1 every 180 years
E) 1 every 0.5 year (2 a year)

Question 80

The dwarf planet Eris is covered in methane ice, whereas the surface of Saturn's moon Enceladus is covered in water ice.Why does methane exist in ice form on Eris but not Enceladus?