Deck 10: Vagabonds of the Solar System

Question 1

Earth's Moon subtends an angle of about 0.5° when viewed from Earth. Charon is about 1200 km in diameter and about 18,490 km away from the surface of Pluto. How large an angle does it subtend when viewed from Pluto?

A) about the same size angle as Earth's Moon
B) about 7 times larger an angle than Earth's Moon
C) about 11 times larger an angle than Earth's Moon
D) over 100 times larger an angle than Earth's Moon

Answer 1

about 7 times larger an angle than Earth's Moon

Question 2

The dwarf planet Pluto appears to be composed of

A) rock and iron.
B) a mixture of rock and ice.
C) gases such as methane and ammonia, possibly with a small, liquid core.
D) the very lightest elements, hydrogen and helium.

Answer 2

a mixture of rock and ice.

Question 3

Which one of these is a small solar system body?

A) Rhea, a moon of Saturn
B) Pluto
C) Ceres (an asteroid)
D) Mathilde (an asteroid)

Answer 3

Mathilde (an asteroid)

Question 4

What is unique about the Pluto-Charon system, compared with all other planets and dwarf planets in the solar system?

A) Both Pluto and Charon are volcanically active, with lava flows and vents of sulfur dioxide gas.
B) Charon is an icy moon, but it is in orbit around a giant planet made mostly of liquid hydrogen.
C) Pluto has only one satellite.
D) Both Pluto and Charon are in synchronous rotation, so each object maintains the same face toward the other object at all times.

Question 5

Which of these solar system objects has the greatest orbital eccentricity and therefore the MOST elliptical orbit?

A) Mercury
B) Mars
C) Earth
D) Pluto

Question 6

Compared to the planets in the solar system, the dwarf planet Pluto is

A) similar to the Jovian planets in composition, although it is much smaller in size.
B) similar to the terrestrial planets in composition, although it is much smaller in size.
C) similar to the terrestrial planets in composition, although it is much larger in size.
D) a real oddity, denser than the Jovian planets but lighter than the terrestrial planets.

Question 7

What is the largest moon of the dwarf planet Pluto called?

A) Chiron
B) Callisto
C) Charon
D) Triton

Question 8

Which of these solar system objects has the greatest orbital inclination (orbit at the greatest angle to that of Earth's orbit around the Sun)?

A) Mercury
B) Mars
C) Jupiter
D) Pluto

Question 9

Which of these objects was farthest from the Sun in 1990?

A) Pluto
B) Charon
C) Neptune
D) Uranus

Question 10

Which planet or dwarf planet in the solar system has the moon with the largest diameter compared with the diameter of the planet or dwarf planet itself?

A) Earth
B) Saturn
C) Neptune
D) Pluto

Question 11

How was the dwarf planet Pluto discovered?

A) by prediction using Newton's laws to account for the deviations from uniform orbits of Uranus and Neptune
B) by the infrared cameras on the IRAS spacecraft
C) by Voyager spacecraft cameras, which were used between planetary encounters to survey the planetary system
D) by searching photographs of the sky for an object that moved against the background of distant stars

Question 12

The Pluto-Charon system moves in which way in its mutual motion?

A) Charon orbits Pluto with exactly Pluto's rotation period.
B) Charon orbits Pluto once while Pluto rotates twice.
C) There is no relationship between rotation period of Pluto and orbital period of Charon.
D) Charon orbits Pluto twice while Pluto rotates once.

Question 13

Pluto is believed to have

A) no atmosphere at all.
B) a thick atmosphere of carbon dioxide.
C) a thin atmosphere of water vapor.
D) a thin atmosphere containing some nitrogen, methane, and carbon monoxide.

Question 14

Pluto was discovered in

A) 1930.
B) 1846.
C) 1609.
D) 1781.

Question 15

Pluto is NOT believed to have an unusually large

A) number of craters.
B) satellite (relative to its own size).
C) orbital eccentricity.
D) orbital inclination.

Question 16

Pluto's mass was poorly known before 1978. What happened in that year to change this?

A) The Hubble Space Telescope was launched.
B) The new Keck telescopes became operational.
C) Charon was discovered.
D) The return echo of a radar pulse, sent many years before, returned to Earth allowing a Doppler shift measurement of its rotation rate.

Question 17

What technique allowed scientists to determine accurately, for the first time, the relative sizes of Pluto and Charon?

A) imaging by the Voyager spacecraft in 1989
B) direct photography using adaptive-optics telescopes on Earth in 1995
C) occultation of this planet by Earth's Moon during the 1980s
D) eclipses of the planet's surface by its moon, Charon, during 1985-1990, viewed from Earth

Question 18

Some of the definitions of the different types of objects in the solar system overlap. Which one of these pairs does NOT overlap? That is, if an object can be described by one of the labels, it cannot be described by the other.

A) dwarf planet and asteroid
B) dwarf planet and Kuiper belt object
C) satellite and Kuiper belt object
D) meteoroid and planet

Question 19

How often would an observer standing on Pluto's surface see the satellite Charon rise above the horizon each day?

A) once each 6-hour day as Pluto rotates on its axis
B) twice each 6-hour day because Charon is in a retrograde orbit
C) once every 2 days because Charon orbits in the same direction Pluto rotates but more slowly
D) never-Charon is a synchronous satellite with an orbital period exactly equal to Pluto's rotation period

Question 20

Which of these objects was discovered during the twentieth century?

A) Pluto
B) Uranus
C) Neptune
D) Ceres

Question 21

The size of the largest asteroid, Ceres, compared with the largest mare or impact basin on the Moon, which covers about one-quarter of the Moon's face, is

A) not comparable because all asteroids are very small objects (1 km diameter), whereas most maria are large (100-1000 km diameter).
B) much smaller, only about 1/3 the size.
C) very similar, about 1000 km across.
D) much larger, by a factor of more than 2.

Question 22

Haumea is classified as a dwarf planet even though its shape resembles a watermelon. Why is it so distorted?

A) It has a massive, nearby moon.
B) Its two hemispheres have very different densities.
C) It has recently undergone a collision.
D) It rotates rapidly.

Question 23

On New Year's Day, 1801, Giuseppe Piazzi discovered the asteroid Ceres. His search was inspired by an event that had occurred only about 20 years before. What event?

A) first astronomical use of the telescope by Galileo
B) invention of the first practical reflecting telescope by Newton
C) discovery of Uranus by Herschel
D) discovery of Pluto by Tombaugh

Question 24

What is a trans-Neptunian object?

A) a solar system object that may impact Neptune in the next billion years
B) a moon of Neptune
C) a solar system object that orbits the Sun with a semimajor axis larger than Neptune's
D) an exoplanet roughly the same mass as Neptune

Question 25

What is the largest known asteroid in the solar system?

A) Phobos
B) Gaspra
C) Ceres
D) Pallas

Question 26

Which of these is LARGER than Pluto?

A) Eris
B) Ceres
C) Haumea
D) Earth's Moon

Question 27

When compared with the diameter of Earth's Moon, the diameters of the biggest asteroids are

A) very much smaller (less than 1/10).
B) about the same size.
C) very much larger, by a factor of at least 5.
D) between 1/10 and 1/3 as large.

Question 28

A few of the largest asteroids appear to be spherical. How does this occur?

A) The visible outer atmospheres of these large asteroids are spherical even though the underlying surfaces are irregular.
B) The largest asteroids solidified from spherical gas clouds in their early history and retained this shape.
C) Repeated collisions with other asteroids have worn the largest asteroids down to spheres.
D) Self-gravity was sufficient to pull the largest asteroids into a spherical shape during their early history.

Question 29

Haumea is all of these EXCEPT

A) a trans-Neptunian object.
B) a dwarf planet.
C) a Kuiper belt object.
D) an asteroid.

Question 30

Unlike the other dwarf planets in the Kuiper belt, Makemake has no moons. Is this important?

A) No. Having or not having a moon does not affect what astronomers can learn about a solar system body.
B) Yes. It indicates that Makemake is older than the others.
C) Yes. It indicates that Makemake is younger than the others.
D) Yes. It means that it is harder to determine the mass of Makemake.

Question 31

The asteroid belt exists between the orbits of the planets

A) Earth and Mars.
B) Jupiter and Saturn.
C) Venus and Earth.
D) Mars and Jupiter.

Question 32

What is unusual about the surface of Haumea's moons?

A) It is solid rock.
B) It appears to be a mixture of rock and ice.
C) It is almost pure water ice.
D) It is almost perfectly round.

Question 33

If all the material in the asteroid belt were to be combined to produce a planet, how big would it be?

A) about 1500 km in diameter, less than half the diameter of the Moon
B) only a few kilometers in diameter, similar to an average mountain on Earth
C) about the size of Earth, with a diameter of about 13,000 km
D) about the size of Mercury, with a diameter of about 5000 km

Question 34

The first satellite discovered in orbit about Pluto was Charon. What is unusual about this moon?

A) Charon is the only moon in the solar system known to have an atmosphere.
B) Charon is much warmer than it should be, given its position in the solar system.
C) Compared with planet-satellite systems in the rest of the solar system, Charon is very large and very close to Pluto.
D) Charon is geologically active.

Question 35

Which of these is LEAST similar in size to Pluto?

A) Ceres
B) Mercury
C) Makemake
D) Eris

Question 36

Who was the first person to discover an asteroid?

A) German astronomer Johann Bode
B) English astronomer Sir William Herschel
C) German mathematician Karl Friedrich Gauss
D) Italian astronomer Guiseppe Piazzi

Question 37

What is the diameter of Ceres, the largest asteroid in the solar system, compared with the diameter of Earth, which is about 12,800 km?

A) smaller than 1/100 Earth's diameter
B) slightly less than 1/10 Earth's diameter
C) about 1/4 Earth's diameter
D) about 1/2 Earth's diameter

Question 38

Most of the asteroids of the solar system move around the Sun between the orbits of which planets?

A) Earth and Mars
B) Jupiter and Saturn
C) Venus and Earth
D) Mars and Jupiter

Question 39

According to the Dawn flyby of asteroid Vesta, which of these is NOT a characteristic of Vesta?

A) It shows chemical differentiation.
B) It is orbited by its own satellite.
C) Its hemispheres show different amounts of cratering.
D) It possesses at least one very tall mountain.

Question 40

Which solar system object was found on January 1, 1801, located between the orbits of Mars and Jupiter?

A) asteroid Ceres
B) Comet Halley
C) Kuiper belt object 1993 SC
D) asteroid Gaspra

Question 41

The asteroid belt is believed by most astronomers to be composed of

A) rocky debris left over from the formation of the solar system.
B) former moons of Jupiter.
C) rather dirty ice balls similar to the nuclei of comets.
D) the remnants of a gaseous planet disrupted by a massive impact.

Question 42

How would a typical asteroid appear on a time exposure photograph of the sky as it orbited the Sun if the camera were tracking the background stars?

A) The asteroid would look like a star, a small extra dot not shown on star charts of this area of the sky.
B) The asteroid would look like a small, diffuse patch against the sharp images of stars because of the dust and gas surrounding it.
C) The asteroid would produce a flash of light as it crossed the field of view of the camera.
D) The asteroid would produce a short trail as it moved slowly against the background stars.

Question 43

By 1891 only about 300 asteroids had been discovered. After 1891 hundreds more were discovered quickly. What caused this increased discovery rate for asteroids?

A) invention of the telescope
B) invention of photography
C) advent of astrophotography
D) heightened interest in the solar system fueled by Percival Lowell and the Martian canals controversy

Question 44

The number of known asteroids rose sharply in the 1890s. What caused this?

A) The technique of astrophotography was introduced.
B) The first very large telescopes were built.
C) Better theoretical predictions of where to look for asteroids became available.
D) A series of collisions involving large objects between the orbits of Mars and Jupiter resulted in many more asteroids being formed.

Question 45

One of the Kirkwood gaps in the asteroid belt is described as "3/7 of Jupiter's orbital period." What does this mean?

A) This location corresponds to the radius where an asteroid would complete 3 solar orbits in the same time Jupiter completes 7 solar orbits.
B) This location corresponds to the radius where an asteroid would complete 7 solar orbits in the same time Jupiter completes 3 solar orbits.
C) This location corresponds to a radius that is 3/7 of the orbital radius of Jupiter.
D) The asteroids are apparently the remnants of material that never formed into a larger body. If that body had orbited at this location it would have had 3/7 of Jupiter's mass.

Question 46

Jupiter's orbital period is approximately 12 years. Based on this number, astronomers would be MOST likely to find an asteroid belt asteroid with a period of how many years?

A) 4
B) 6
C) 7.3
D) 24

Question 47

The Kirkwood gaps are in the

A) asteroid belt at places where there are very few asteroids.
B) rings of Saturn, where there is less material than at other radii.
C) spectrum of hydrogen gas, where light has been absorbed by molecules first identified by Kirkwood.
D) equatorial region of the Sun, where no sunspots are found.

Question 48

Which of these statements about asteroids is NOT true?

A) Only a minority of all asteroids are in the asteroid belt.
B) Some asteroids have orbits that carry them inside Earth's orbit.
C) Some asteroids occupy the same orbit as Jupiter.
D) The total mass of all asteroids is much smaller than the mass of Earth.

Question 49

What effect does Jupiter have on asteroids in the asteroid belt at the present day?

A) Jupiter has no effect whatever on such small objects because they are a long way away from Jupiter, and Jupiter's gravitational influence varies as the inverse square of distance, by Newton's law.
B) Jupiter perturbs only the orbits of asteroids whose orbital periods are a simple fraction of its orbital period.
C) Jupiter disturbs only the orbits of asteroids whose orbital distances (or semimajor axes) are a simple fraction of the radius of Jupiter's orbit.
D) Jupiter disturbs the orbits of all the asteroids in the belt, slowing them down and causing them to spiral slowly in toward the Sun.

Question 50

What is the relationship between the Kirkwood gaps in the asteroid belt and the Cassini division in the rings of Saturn?

A) Both the Kirkwood gaps and the Cassini division are caused by large objects passing through swarms of smaller objects, sweeping out gaps in the swarms.
B) Both the Kirkwood gaps and the Cassini division were discovered by observers from the same group; Kirkwood and Cassini both worked at the same observatory.
C) Both the Kirkwood gaps and the Cassini division are caused by disruptions of the orbits of small objects by larger planets or moons. In both cases, the orbital distance of small objects in the gaps is related by simple fractions to the orbital distance to the disturbing object.
D) Both the Kirkwood gaps and the Cassini division are caused by disruptions of the orbits of small objects by larger planets or moons. In both cases, the periods of the small objects are simple fractions of those of the larger disturbing object.

Question 51

The number of asteroids with diameters greater than 100 km is

A) just over 1000.
B) 3.
C) about 30.
D) about 290.

Question 52

Why does no major planet orbit the Sun at the location of the asteroid belt?

A) One such object did form there but was destroyed by a collision with an early comet; the asteroid belt is the debris from the collision.
B) Jupiter's gravitational pull stirred up the planetesimals, preventing them from coalescing into a single large object.
C) In the early solar nebula, the temperature that close to the Sun was too high for rock or iron to condense into solid form.
D) Three Earth-sized planets did form there, but they destroyed each other by mutual collisions; the asteroid belt is the debris from these collisions.

Question 53

The average sidereal period for an asteroid moving around the Sun in the asteroid belt, according to Kepler's law, is

A) 46.8 years.
B) 2.8 years.
C) 4.68 years.
D) 1.99 years.

Question 54

What is the typical distance between asteroids in the asteroid belt?

A) 6000 km
B) 1.2 au
C) 25 km
D) 1 million km

Question 55

The asteroid belt has a gap where few objects are found because of repeated gravitational disturbances from Jupiter. At what distance from the Sun will this gap be found if objects in the gap have a period one-third that of Jupiter? (Hint: Jupiter's orbital period is about 12 years.)

A) 8 au
B) 3.5 au
C) 2.5 au
D) 1.4 au

Question 56

Computer simulations of the formation of the solar system show that the material in the vicinity of the asteroid belt is NOT in the form of one large planet because

A) most of the material originally in the asteroid belt crashed into Mars, creating the heavily cratered terrain seen there.
B) a violent collision destroyed two protoplanets, the debris from which became the asteroid belt.
C) this region is where the gravitational field of the Sun is exactly balanced by that of Jupiter.
D) Jupiter's gravitational pull prevented them from coalescing into a planet.

Question 57

The Kirkwood gaps are caused by

A) large asteroids moving in circular orbits within the asteroid belt, which sweep out and collect smaller objects in their path.
B) large asteroids whose orbits carry them periodically through the asteroid belt, where they sweep out a path and leave it devoid of asteroids.
C) the gravitational pull of Jupiter, which nudges asteroids into new orbits.
D) large asteroids on the outer fringe of the asteroid belt, which gravitationally affect the paths of smaller objects within the belt.

Question 58

The total number of asteroids orbiting the Sun in the main belt is estimated to be

A) several thousand.
B) hundreds of billions.
C) more than ten million.
D) a few hundred.

Question 59

If an asteroid was moving in a circular orbit around the Sun with an orbital period of 1/5 that of Jupiter, what would be the radius of its orbit? The semimajor axis of Jupiter's orbit is 5.2 au.

A) 1.78 au
B) 15.2 au
C) 1.04 au
D) 3.65 au

Question 60

Jupiter's orbital period is approximately 12 years. If it were exactly 12 years, which of these periods would NOT produce an effective resonance with Jupiter?

A) 3.0 years
B) 6.0 years
C) 5.1 years
D) 8.0 years

Question 61

What is the orbital sidereal period of a Trojan asteroid?

A) The Trojan asteroids have different orbital periods, depending on their masses.
B) 5.9 years, the same as most asteroids in the asteroid belt
C) 11.86 years, the same as Jupiter
D) 1.88 years, the same as Mars

Question 62

What is a Hirayama family of asteroids?

A) group of asteroids that have nearly identical orbits
B) either of two groups of asteroids that orbit at Jupiter's distance from the Sun
C) group of asteroids that have identical spectra and therefore identical compositions
D) group of asteroids that have orbits that cross Earth's orbit but remain outside Venus's orbit

Question 63

In the orbits of which of the planets do Lagrange points occur?

A) all planets
B) Jupiter; only Jupiter is massive enough to produce a Lagrange point.
C) Jupiter and the planets beyond it; a Lagrange point must be a certain distance from its planet, and only the orbits of Jupiter and the planets beyond it are large enough to accommodate a Lagrange point.
D) only the planets with moons

Question 64

What is the magnitude of the net force on a Trojan asteroid?

A) zero
B) the same as the net force on Jupiter
C) slightly less than the net force on Jupiter if it is 60 degrees ahead of Jupiter in its orbit, and slightly more if it is 60 degrees behind
D) enough to give it the same acceleration as Jupiter

Question 65

Asteroids whose orbits carry them across Earth's orbit are known as

A) Kirkwood asteroids.
B) Amor asteroids.
C) Trojan asteroids.
D) Apollo asteroids.

Question 66

What is unusual about the asteroid Karin?

A) Karin is the Apollo asteroid that comes closest to Earth.
B) Karin was the first of the Trojan asteroids to be discovered.
C) Karin sits at the stable Lagrange point in Earth's orbit.
D) Karin is the largest asteroid in a cluster of asteroids that all orbit the Sun together.

Question 67

How are space probes to the outer planets such as Jupiter protected from being obliterated by collisions with asteroids in the asteroid belt?

A) They aren't. Only one out of every four spacecraft is lost to collisions with asteroids, so it is less expensive to take this risk.
B) The spacecraft are equipped with cameras to detect asteroids so that they can be directed safely around them.
C) The spacecraft are sent in an inclined orbit that arcs above or below the asteroid belt, and then they cross the ecliptic again near Jupiter.
D) They aren't. Asteroids are so far apart that the spacecraft just sail through.

Question 68

How could astronomers detect a large asteroid if it were heading straight for Earth?

A) The asteroid would appear as a slowly brightening starlike object where no star was previously charted, with a redshifted solar spectrum of reflected light.
B) The asteroid would appear as a short trail against the background stars on a sky-tracked long-exposure photograph, and its spectrum would show no Doppler shift.
C) The asteroid would appear as a slowly brightening point of light where no star had previously been charted, and the spectrum of sunlight reflected from it would be blueshifted by the Doppler effect.
D) The asteroid would appear as a slowly brightening and growing diffuse sphere of light where no star was charted because of light scattered from the dust and gas surrounding it, and it would show a blueshifted spectrum.

Question 69

Asteroids that orbit the Sun in the stable Lagrange points in Jupiter's orbit are known as

A) adenoids.
B) Apollo asteroids.
C) Trojans.
D) Jupitoids.

Question 70

The two stable Lagrange points in the Jupiter-Sun planetary system are

A) positions in space at Jupiter's orbital distance from the Sun where the combined gravitational forces from the Sun and Jupiter produce an equilibrium point at which asteroids can become trapped.
B) points at high latitudes on Jupiter where auroras (called Lagrange auroras on Jupiter) occur most frequently.
C) areas in the asteroid belt where gravitational interaction of Jupiter with asteroids disturbs their orbits and causes a Kirkwood gap.
D) an area between the Sun and Jupiter where the gravitational forces on an object from these massive bodies are equal and opposite.

Question 71

If an asteroid were found to be orbiting in a circular path around the Sun at the same distance as Jupiter (5.2 au), what would be its orbital period compared with that of Jupiter, which is 11.86 years?

A) about 10 times as long as Jupiter's period, or 118.6 years, because the Sun's gravitational force is much smaller on such a small object
B) about 1/10 of Jupiter's period because it is a much smaller object
C) same as Jupiter's period, 11.86 years
D) exactly 1/2 of Jupiter's period, or 5.93 years, because it would be in a synchronous orbit with Jupiter

Question 72

One significant feature of the Lagrange points produced by the Sun and Jupiter is that

A) they are regions of reduced gravitational force in the asteroid belt from which asteroids can escape, producing the gaps within the belt.
B) gravitational forces combine to trap asteroids at these points.
C) gravitational forces combine to enhance the overall force on particles passing through them, accelerating them out of the solar system.
D) they are points of maximum gravitational force near Jupiter, where the major moons Io and Europa are held.

Question 73

What kind of orbit is traced by the Trojan asteroids as they move around the Sun?

A) elliptical orbits that carry them from outside Neptune's orbit to inside the orbit of Jupiter
B) long, elliptical orbits that cross the orbit of Earth
C) circular orbits at Jupiter's orbital distance, at angles of ±60° away from the planet
D) circular orbits at about 2.8 au from the Sun, within the asteroid belt

Question 74

Which of these characteristics has NOT been observed in an asteroid?

A) regolith
B) craters
C) satellites
D) plate tectonics

Question 75

Often, an asteroid viewed from Earth appears to change its brightness periodically because the

A) albedo is significantly different on one side than the other.
B) leading side is very dark and the trailing side is very bright like Iapetus, a satellite of Saturn.
C) asteroid is elongated, so it may present a larger or a smaller cross section to Earth as it rotates.
D) asteroid is simply passing through the shadow of another asteroid.

Question 76

What is the average distance between asteroids?

A) about 3 times the length of a football field
B) about twice the diameter of Earth
C) about half the distance between Earth and the Moon
D) many times the distance between Earth and the Moon

Question 77

Which of these is NOT true of asteroids in the solar system?

A) The masses of all the known asteroids in the asteroid belt, added together, would produce a body too small to be classified as a planet.
B) All known asteroids orbit between Mars and Jupiter.
C) Despite the vast average separations between asteroids, they can sometimes collide.
D) Almost all asteroids have orbits that lie near the plane of the ecliptic.

Question 78

Why is the star Zeta Leporis, in Lepus the Hare, an object of particular interest?

A) Zeta Leporis is still in the nebular stage; it is only a few hundred million years old.
B) Zeta Leporis appears to have an Earthlike planet.
C) Zeta Leporis is believed to have passed near the Sun early in the history of the solar system, causing gravitational disruptions that affect the orbits of the asteroids.
D) Zeta Leporis appears to have an asteroid belt of its own.

Question 79

Which of these is NOT a reason to believe asteroids have collisions with each other?

A) Astronomers have observed satellites of asteroids that appear to have been captured after collisions.
B) Almost all of the asteroids orbit the Sun in the same direction.
C) There are several families of asteroids with very similar orbits.
D) Astronomers have observed asteroids that appear to be two lobes connected by a narrow collar, as though two asteroids had collided and stuck together.

Question 80

Where do the Trojan asteroids orbit the Sun?

A) in nearly circular orbits at the same orbital distance as Jupiter
B) in nearly circular orbits at the same orbital distance as Earth
C) in the asteroid belt
D) in elliptical orbits that cross the orbit of Earth