Deck 4: Formation of the Solar System and Other Planetary Systems

Question 1

What fraction of the mass of the universe is in the form of atoms other than hydrogen and helium?

A) 10%
B) much less than 1%
C) 2%
D) 50%

Answer 1

2%

Question 2

Where in the universe are heavy elements with masses greater than that of helium being produced at this time?

A) in the central cores of stars
B) in the surface layers of stars
C) at the event horizons of massive black holes
D) in the dark clouds of dust and gas

Answer 2

in the central cores of stars

Question 3

The solar system formed about how long after the Big Bang?

A) immediately
B) a few hundred million years
C) nine billion years
D) 13.8 billion years

Answer 3

nine billion years

Question 4

Where was all the hydrogen in the universe formed?

A) in nuclear reactions in the cores of stars
B) in supernovae (exploding stars)
C) in the dark clouds of dust and gas
D) in the Big Bang, at the very beginning of the universe

Question 5

What fraction of the mass of Earth is made up of the elements hydrogen and helium?

A) about 70%
B) 2%
C) much less than 1%
D) 98%

Question 6

The MOST abundant material in the universe is:

A) nitrogen.
B) carbon dioxide.
C) water.
D) hydrogen.

Question 7

The universe contains about ten times as many hydrogen atoms as helium atoms,but a helium atom has four times the mass of a hydrogen atom.What is the approximate ratio of the universe's hydrogen to helium by mass?

A) 2.5 to 1
B) 10 to 1
C) 4 to 1
D) 1 to 4

Question 8

In the Nice model of solar system formation:

A) all of the outer planets formed at the same time.
B) Jupiter and Saturn formed first, followed by Uranus and Neptune.
C) Neptune and Uranus formed first, followed by Jupiter and Saturn.
D) the inner planets formed before the outer planets.

Question 9

The composition of matter in the universe can be summarized by which statement?

A) All but 2% of the mass of the universe is hydrogen and helium.
B) All but 2% of the mass of the universe is hydrogen.
C) Two percent of the mass of the universe is hydrogen and helium; the rest is of heavier elements.
D) About half of the mass of the universe is in the form of rocks, molecules, and planetary material.

Question 10

What is thought to be the physical mechanism that was responsible for the present mix of chemical elements in the universe?

A) All the known elements have been formed by the breakup (radioactivity) of the heavy elements formed in the initial Big Bang.
B) All the known elements were formed in the Big Bang.
C) Hydrogen and helium were formed in the Big Bang, whereas the heavier elements have been slowly forming by collisions in cold interstellar gas clouds.
D) Hydrogen and helium were formed in the Big Bang, whereas the heavier elements were made in the centers of stars.

Question 11

Most of the elements beyond hydrogen and helium in the periodic table in the Sun and the solar system most probably originated in:

A) the center of our own Sun, through fusion and later ejection as solar wind.
B) chemical reactions in planetary atmospheres.
C) the original Big Bang of the universe.
D) fusion reactions in the centers of earlier stars.

Question 12

What is a planetary nebula?

A) a nebula of gas and dust around a giant planet
B) a nebula of gas and dust around any planet
C) the result of a relatively gentle stellar outburst in which matter is ejected into space
D) the result of a violent stellar outburst in which the entire star is blown apart

Question 13

The MOST likely mechanism for the solar system is that the:

A) Sun and planets slowly condensed to their present form from a gas and dust cloud.
B) Sun captured the planets as they drifted through space.
C) solar system was once a galaxy from which the Sun and planets are the remnants, after evolution.
D) planets were spun out of the Sun as smaller gas clouds and subsequently condensed.

Question 14

Most of the weight of our bodies comes from heavy elements such as carbon and oxygen.This fact immediately tells us that:

A) our bodies have converted the original hydrogen and helium into heavier elements.
B) the Big Bang model of the universe must be wrong.
C) the solar system did not form directly from the material created by the Big Bang.
D) the Big Bang created elements unevenly because the Sun, unlike our bodies, is mostly hydrogen and helium.

Question 15

Only three elements are believed to have formed directly in the Big Bang.These elements do NOT include:

A) hydrogen.
B) lithium.
C) oxygen.
D) helium.

Question 16

The MOST common elements in the universe are:

A) about equal amounts of all elements up to iron but very little of any heavier elements.
B) hydrogen and helium, with small amounts of heavier elements.
C) nitrogen and oxygen, with smaller quantities of hydrogen, helium, and heavier elements.
D) heavy elements, with smaller quantities of hydrogen and helium.

Question 17

Fusion is the process by which:

A) dust grains and ice crystals coalesce to form planetesimals.
B) massive protoplanetary cores pull gas onto themselves to create giant planets.
C) clouds of interstellar gas and dust contract to form protostars.
D) elements are transformed into heavier elements by nuclear reactions.

Question 18

What was the material from which the solar system formed?

A) a nebula made mostly of heavy elements but enriched in hydrogen and helium from supernova explosions
B) debris from the explosion of a massive star
C) a nebula made entirely of hydrogen and helium gas
D) a nebula made mostly of hydrogen and helium gas but enriched in heavier elements from supernova explosions

Question 19

MOST of the mass of the universe-98%-is in the form of:

A) hydrogen and helium.
B) nitrogen and oxygen.
C) iron and silicon.
D) hydrogen.

Question 20

Hydrogen and helium together account for what percentage of the total mass of all the matter in the universe?

A) 90%
B) 98%
C) 75%
D) about 50%

Question 21

Which statement describes the distribution of light and heavy elements in the solar system?

A) The heavy elements are generally within a few astronomical units of the center, while the light elements are generally farther from the center.
B) The light elements are generally within a few astronomical units of the center, while the heavy elements are generally farther from the center.
C) Both the light and heavy elements are generally within a few astronomical units of the center.
D) Both the light and heavy elements are generally farther than a few astronomical units from the center.

Question 22

In the solar system,what is the snow line?

A) either one of a pair of lines on any planet, parallel to its equator, between which snow is never found
B) a boundary in the solar system such that ices of water, carbon dioxide, methane, and ammonia are found only outside of this line (i.e., farther from the Sun)
C) a boundary in the solar system such that all fluids outside of this line (i.e., farther from the Sun) must be frozen
D) a boundary within the asteroid belt that divides the asteroids into those composed of rock and those composed of ice

Question 23

What process heated the early solar nebula as it slowly condensed toward a central protosun?

A) the radioactive decay of heavy elements originally formed in the Big Bang
B) the release of heat as molecules formed and gases condensed into ices
C) thermonuclear fusion in the protosun, followed by radiative heating of the nebula
D) the release of heat by collisions of particles as they gained kinetic energy in falling toward the center of the nebula

Question 24

All of the descriptions EXCEPT ONE is believed to be a possible mechanism that can trigger the collapse of a cloud of gas and dust to form a star.Which is the exception?

A) Stellar winds may compress nearby gas and dust clouds.
B) A nearby supernova can compress nearby gas and dust clouds.
C) Clouds can collide and compress each other.
D) Radiation pressure from the Cosmic Microwave Background can compress clouds of gas and dust.

Question 25

The mass of the solar nebula that began contracting to form the solar system was estimated to be:

A) one solar mass, the same as the mass of the solar system today.
B) only a fraction of a solar mass because additional mass has since been attracted from nearby objects.
C) several solar masses.
D) thousands of solar masses to allow for the mass energy radiated away since the formation.

Question 26

Why did the temperature start to rise at the center of the solar nebula?

A) Supernova explosions were stirring up the material there and causing turbulence.
B) The nebula was contracting, which increased the speed of the atoms moving in it.
C) Fusion reactions were beginning in the core, releasing tremendous amounts of heat.
D) Massive stars nearby were heating the nebula with their ultraviolet radiation.

Question 27

What is the Jeans instability?

A) When a growing protoplanet becomes too large, it is more likely to be split apart by subsequent bombardment than to grow further.
B) If a solar nebula is too massive, it will continue to collapse to become a black hole and will not form planets.
C) If the disk of matter surrounding a solar nebula becomes too hot, it will dissipate, and planets will not form.
D) If a cloud of gas and dust is sufficiently dense, it will collapse due to its own gravity.

Question 28

The nebular hypothesis of the formation of the solar system assumes that the material that became the solar system began as a large spherical cloud of gas and dust,rotating slowly.As the solar system formed,most of this material was transformed into a compact,flattened disk,rotating more rapidly.What is the explanation for this change in shape and rate of rotation?

A) conservation of angular momentum
B) the influence of nearby stars
C) differentiation of materials easily vaporized and not easily vaporized
D) alignment with the plane of the Milky Way Galaxy

Question 29

Accretion is the process by which:

A) elements are transformed into heavier elements by nuclear reactions.
B) massive protoplanetary cores pull gas onto themselves to create giant planets.
C) clouds of interstellar gas and dust contract to form protostars.
D) dust grains and ice crystals coalesce to form planetesimals.

Question 30

The material from which our solar system formed is believed to be:

A) the hot, dense gases at the center of a globular star cluster.
B) a vast cloud of pure hydrogen.
C) the convergence of the solar winds of several nearby stars.
D) a cold, dark cloud of gas and dust.

Question 31

A gas and dust cloud will not necessarily collapse because it normally experiences a balance between its internal gas pressure and:

A) kinetic energy.
B) friction.
C) gravity.
D) electrostatic repulsion.

Question 32

A gas and dust cloud that is unstable and will collapse is characterized by all the factors EXCEPT ONE.Which is the exception?

A) low temperature
B) rapid internal motion
C) low pressure
D) high density

Question 33

The MOST probable theory for the formation of the solar system is:

A) an encounter in which a passing star ripped off material from the Sun to form the planets.
B) a capture theory in which the Sun, after formation, captured objects moving through space to form the planets.
C) the condensation of a nebula of cold gas and dust into the Sun and planets.
D) the condensation of a nebula of hot gas into the Sun and planets.

Question 34

What are the three "common" substances that are believed to be important in planet formation?

A) electromagnetic radiation, electrical discharges (e.g., lightning), and water
B) rock, ices, and gas
C) solid, liquid, and gaseous hydrogen
D) hydrogen, helium, and neon gases

Question 35

Which physical parameter more than any other most probably controlled the early evolution of the planetary system and dictated the characteristics of the planets that eventually formed?

A) the mix of chemical constituents
B) overall rotation of the nebula
C) temperature distribution in the nebula
D) the density of hydrogen gas in the nebula

Question 36

What is a protoplanetary disk?

A) a disk of gas and dust, such as those observed around some stars in the Orion nebula
B) a disk of debris around a planet of greater mass than Jupiter, material from which rings and moons will form
C) a disk of debris orbiting an exoplanet, for example, the planet orbiting the star 51 Pegasi
D) a disk of cold debris orbiting far from a star, such as the Oort cloud of our solar system

Question 37

What name is given to the concentration of mass that formed at the center of the solar nebula and eventually became the Sun?

A) the solar hub
B) the anti-sun
C) the pseudo-sun
D) the protosun

Question 38

Strong evidence for the existence of planetary systems in the process of formation around other stars comes from:

A) spectroscopic evidence of large quantities of molecules such as ammonia and methane, which can exist only in planetary atmospheres.
B) photographs and infrared observations of disks of dust.
C) detection of very regular pulses of radio energy from some stars.
D) direct photography of actual planets near other stars.

Question 39

There is very little hydrogen or helium in the inner part of the solar system today.We believe the reason for this is that:

A) all the light elements went into the formation of the Sun itself and little were left over for the rest of the solar system.
B) the intense radiation from the early Sun drove the light elements out of the inner solar system.
C) heavier elements were attracted in from the outer part of the solar system, displacing the light elements that were originally in the inner part.
D) the light elements underwent chemical reactions and were locked up in chemicals in the inner solar system.

Question 40

The birthplace of the Sun and planets (and of other stars and maybe their planets)is thought to have been in:

A) cool gas and dust clouds.
B) the centers of supernova explosions.
C) black holes dotted about the universe.
D) the centers of galaxies.

Question 41

Suppose that observers using the Hubble Space Telescope detect around several solar-type stars the presence of planets with the following characteristics: low density,large size,fluid surfaces,rapid rotation.How would these planets be classified in terms of our solar system?

A) asteroids
B) comet nuclei
C) terrestrial planets
D) Jovian planets

Question 42

Which planet in our solar system has the LARGEST mass?

A) Saturn
B) Earth
C) Uranus
D) Jupiter

Question 43

According to current theories of planetary formation,why is Saturn less massive than Jupiter?

A) Saturn formed far out in the solar system, where gas and dust were not as readily available as where Jupiter formed near the Sun.
B) Saturn formed in the inner part of the solar system, where the rocky inner planets had already absorbed most of the material.
C) Saturn was originally more massive but has been repeatedly struck by large planetesimals that have stripped off some of its matter.
D) Jupiter formed first.

Question 44

The manner in which the large,outer planets formed in our solar system was MOST likely the:

A) gravitational condensation of hydrogen, helium, and dust in eddies or vortices in the outer solar nebula.
B) gravitational condensation of hydrogen and helium gas, followed by the capture of planetesimals.
C) accretion of planetesimals to form a core, followed by the gravitational capture of hydrogen and helium gas.
D) accretion of cold planetesimals containing large quantities of hydrogen and helium.

Question 45

The ice giants are:

A) Jupiter and Saturn.
B) Neptune and Uranus.
C) Titan and Pluto.
D) Tatooine and Alderaan.

Question 46

The process of accretion in planetary formation is the:

A) slow condensation by gravity of gas atoms into large, dense gas clouds that are the preplanetary masses.
B) slow acquisition from deep space by the giant planets of their complement of moons by gravitational capture.
C) slow accumulation of solid particles by gravity and collision into larger, solid objects.
D) relatively rapid gravitational collapse (in less than 10⁶ years) of gas clouds to form planets.

Question 47

Suppose the Hubble Space Telescope discovers a series of planets with the following characteristics moving around a star that resembles our Sun: spherical,solid surfaces; mean densities about four times that of water; radii about 4000 km; low-density atmospheres.How would these planets be classified in comparison with our solar system?

A) terrestrial planets
B) Jovian planets
C) cometary nuclei
D) asteroids

Question 48

The MOST probable process for the formation or acquisition of the planets of the Sun is the:

A) capture of planets from outer space by gravity.
B) relatively slow growth of smaller objects by collisions and mutual gravitational attraction.
C) freezing of immense gas clouds by the cold temperature of space.
D) breakup by tidal distortion of a single large companion body to the Sun.

Question 49

The formation of terrestrial-type planets around a star is MOST likely to have occurred through what process?

A) accretion, or slow accumulation of smaller particles by mutual gravitational attraction
B) the breakup of a large disk of matter that formed around the star
C) the capture of objects traversing the depths of space by the star
D) the condensation of gas from the original star nebula

Question 50

Suppose that you were to go back in time and explore the solar nebula during the formation of the solar system.If you were to travel outward from the protosun,the first solid material you would encounter would be:

A) dust-sized grains of rocky material.
B) dust-sized grains of frozen hydrogen, water ice, and rocky minerals.
C) snowflakes made of frozen water, methane, ammonia, and carbon dioxide.
D) snowflakes made of frozen hydrogen and helium.

Question 51

The SMALLEST terrestrial planet is:

A) Neptune.
B) Mars.
C) Ganymede.
D) Mercury.

Question 52

As the forming planet Jupiter moved through the early outer solar system,it collided with huge numbers of gas and dust particles there.What effect did this have?

A) The additional mass made the young Jupiter move faster, causing it to migrate inward to the region where, according to Kepler's third law, periods are shorter and speeds faster.
B) The additional mass made the young Jupiter move more slowly, causing it to migrate outward to the region where, according to Kepler's third law, periods are longer and speeds slower.
C) The additional mass made the young Jupiter move faster, giving it more energy and causing it to migrate outward.
D) The additional mass made the young Jupiter move more slowly, giving it less energy and causing it to migrate inward.

Question 53

Which was the MOST probable time sequence for the formation of the solar system?

A) The Sun contracted first as a gas ball, and the planets and moons formed shortly afterward by accretion and condensation.
B) The Sun formed first, the planets were spun off from the Sun, and the moons in turn were spun off from the planets.
C) The planets formed first out of a cold nebula of gas and dust, followed by the Sun, which formed when the gas had become much hotter.
D) The Sun formed initially, and the planets and major moons were captured much later as they drifted by the Sun.

Question 54

The LARGEST of the terrestrial planets is:

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

Question 55

The early phases of planetary formation into protoplanets were characterized by the:

A) slow accretion of small particles by gravitational attraction and collision.
B) breaking apart of very large objects into planets.
C) condensation of hot gas clouds.
D) violent collapse of matter under gravity.

Question 56

The low average density of the large outer planets,which have high masses and hence high gravitational fields,is an indication of what fact about their interiors?

A) The large, outer planets have hot, gaseous interiors, similar to the interiors of cool stars.
B) The interiors of the large, outer planets are composed of water, methane, and ammonia.
C) The large, outer planets are composed mainly of very light elements, such as hydrogen and helium.
D) The interiors of the large, outer planets have not been condensed to liquid or solid form.

Question 57

Compared with Jupiter and Saturn,Uranus and Neptune contain proportionally more heavy materials,more ices,and less hydrogen.How do we account for this?

A) Jupiter and Saturn migrated inward early during their formation, leaving substantial quantities of heavy materials and ices behind (to form Uranus and Neptune) but taking most of the hydrogen.
B) Neptune and Uranus were formed far out in the solar system, where the materials were different from those in the present location of the outer planets (where Jupiter and Saturn were formed).
C) The heavy materials are from asteroids flung outward by the inward migration of the gas planets, the ices are from icy masses that had spiraled in from far out in the solar system, and the deficit of hydrogen was caused by the prior formation of the gas planets.
D) The heavy materials and ices are from asteroids flung outward by the inward migration of the gas planets, and the hydrogen deficit is because the light gases were blown out of the solar system by the solar wind.

Question 58

The manner in which the terrestrial planets formed was the:

A) gravitational condensation of hydrogen, helium, and dust in eddies or vortices in the solar nebula.
B) gravitational condensation of gas, followed by the capture of solid planetesimals.
C) accretion of solid planetesimals containing mostly rocky material.
D) accretion of planetesimals to form a core, followed by the gravitational capture of gas from the solar nebula.

Question 59

One particularly important collision in the early inner solar system about 100 million years after Earth's formation resulted in the:

A) extinction of 70% of the species then in existence on Earth, including the dinosaurs.
B) formation of a secondary asteroid belt between the orbits of Earth and Venus.
C) destruction of the planet Vulcan, which had an orbit inside the orbit of Mercury..
D) formation of our Moon.

Question 60

The reason for the vast amount of hydrogen in the interior of Jupiter is probably that:

A) nuclear fission of atoms in Jupiter's interior split all nuclei down to hydrogen nuclei early in its history.
B) Jupiter became so hot in its interior that all kinds of atoms and molecules were melted down to the fundamental atom, hydrogen.
C) Jupiter formed from the initial gravitational contraction of hydrogen gas.
D) the mass of the initial condensation of rocks at Jupiter's orbit was sufficient to attract vast amounts of gas to it.

Question 61

The relatively large amount of water found on Earth is believed to have come from:

A) the impact that produced the Moon.
B) water-rich comets.
C) Earth's brief migration outside the snow line.
D) the combination of primordial hydrogen with oxygen produced by green plants.

Question 62

What is a plutino?

A) any object in a 2:3 orbital resonance with Pluto
B) any object in the same orbit as Pluto
C) any object in an orbit outside that of Pluto
D) any object beyond the orbit of Neptune that has enough mass to assume a spherical shape

Question 63

The region at the farthest limits of the solar system in which a large number of objects composed of rock and ice circle the Sun in a roughly spherical region is called the:

A) outer solar system.
B) asteroid belt.
C) Kuiper belt.
D) Oort comet cloud.

Question 64

What is the origin of many of the bodies in the Kuiper belt and the Oort comet cloud?

A) These bodies were part of the original solar nebula. Because they are so far from the rest of the solar system, these regions were undisturbed by the creation of the planets, and these objects have remained there ever since.
B) These distant objects have been captured from interstellar space by the Sun's gravitational pull.
C) The gravitational forces from Jupiter and Saturn flung planetesimals from regions closer to the Sun out into these regions.
D) Early in the history of the solar system, it is believed that these objects were pulled out of the Sun by a close encounter with a passing star.

Question 65

According to our present theory of solar system formation,where were the four inner planets formed?

A) All were formed farther out in the solar system and migrated inward.
B) All were formed near their present locations in the inner solar system.
C) Mercury was formed near the Sun, but the others were formed farther out and migrated inward.
D) Our present theory has no clear answer to this question.

Question 66

Pluto is in a 2:3 resonance orbit with Neptune.What does this mean?

A) During the time that Neptune orbits the Sun three times, Pluto orbits it twice.
B) During the time that Neptune orbits the Sun twice, Pluto orbits it three times.
C) Neptune rotates on its axis three times while Pluto rotates twice about its axis.
D) Neptune's mean orbital radius is 2/3 of Pluto's mean orbital radius.

Question 67

In order to produce a crater,the object that strikes a planet must be larger than about:

A) one centimeter.
B) half a meter.
C) half a kilometer.
D) 50 kilometers.

Question 68

Which statement is NOT true about asteroids and the asteroid belt?

A) The total number of asteroids is between 10,000 and 12,000.
B) All of the asteroids together would make a mass much less than the mass of the Moon.
C) Some asteroids have their own moons.
D) The gravitational influence of Jupiter helps prevent the asteroids from coalescing into a larger body.

Question 69

The large gravitational influences of Jupiter and Saturn forced some planetisimals in their neighborhood to move outward away from the Sun.A consequence of these gravitational forces was:

A) that conservation of angular momentum caused the giant planets to spin faster.
B) collisions that produced many fragments that became the rings of the outer planets.
C) collisions that formed Uranus and Neptune.
D) the creation, or at least enlargement, of the Kuiper belt and the Oort cloud.

Question 70

The composition of a typical asteroid is:

A) rock and metal.
B) ice with a liquid water core.
C) rock and ice.
D) pure ice, or perhaps ice with dust-sized grains of rock mixed in.

Question 71

What process had the greatest influence on the features of the Moon during the first billion years of its existence?

A) erosion by an early, short-lived atmosphere
B) volcanoes
C) impacts from space
D) mountain-building from geological activity

Question 72

The asteroid belt exists between the orbits of which planets?

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

Question 73

The large gravitational influences of the gas planets forced some planetisimals in their neighborhood to move inward toward the Sun.As a consequence of these gravitational forces:

A) these planetisimals became moons around the inner planets.
B) the gas planets themselves were forced outward farther from the Sun.
C) the gas planets also fell inward toward the Sun.
D) these planetesimals fell into the Sun, causing the Sun to flare up and expel the remaining hydrogen and helium from the inner solar system.

Question 74

The region outside the orbit of Neptune in which a large number of objects composed of rock and ice circle the Sun not far from the plane of the ecliptic is called the:

A) outer solar system.
B) asteroid belt.
C) Kuiper belt.
D) Oort comet cloud.

Question 75

The solar system formed about 4.5 billion years ago.What has been the rate of bombardment by space debris in the inner part of the solar system since then?

A) There has been a relatively steady bombardment by both large and small pieces of debris since the formation.
B) The rate of bombardment was very heavy just after the solar system's creation, but the rate has decreased steadily since then.
C) The rate decreased steadily for about 400 million years after the solar system's creation. Then a very heavy bombardment began and lasted about 300 million years. The rate has been greatly reduced since then.
D) The rate has been highly erratic with no clear pattern.

Question 76

What is a plutoid?

A) any object in a 2:3 orbital resonance with Neptune
B) any object in the same orbit as Pluto
C) any object in an orbit outside that of Pluto
D) any object beyond the orbit of Neptune that has enough mass to assume a spherical shape

Question 77

What is the Kuiper belt?

A) a band of dust in the plane of the ecliptic, extending from near the orbit of Mars to beyond the orbit of Pluto
B) the broadest band of asteroids in the asteroid belt, separated from other bands by Kirkwood gaps
C) the relatively flat distribution of objects in the plane of the ecliptic, extending from around the orbit of Pluto out to about 50 AU from the Sun
D) the approximate spherical distribution of comets centered on the Sun and extending out to about 50,000 AU

Question 78

The asteroid Gaspra (see Figure 4-7,Comins,Discovering the Essential Universe,6th ed.)is typical of most asteroids in that it is:

A) potato-shaped with a smooth, metallic surface.
B) spherical and densely covered with craters.
C) potato-shaped with large and small craters.
D) spherical and deformed by thermal activity.

Question 79

The asteroid belt is made up of:

A) irregularly shaped bodies composed primarily of ices.
B) several planet-sized objects with dense methane atmospheres.
C) large, rocky bodies typically about the size of our Moon.
D) rocky bodies with diameters ranging from less than a kilometer to hundreds of kilometers.

Question 80

Where are the asteroids located?

A) Their orbits are distributed more or less uniformly throughout the solar system.
B) All asteroids have orbits between the orbits of Mars and Jupiter.
C) Most asteroids have orbits between the orbits of Mars and Jupiter, but there are gaps caused by resonances with Jupiter.
D) Most asteroids have orbits between the orbits of Mars and Jupiter, but there are gaps caused the motions of the largest asteroids moving through the asteroid belt and sweeping out regions much like the shepherd satellites in the rings of Saturn.