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Chapter 4 The Solar System: Interplanetary Matter and the Birth of the Planets 1) All the terrestrial planets lie inside the asteroid belt. Answer: TRUE Diff: 1 Section Ref.: 4.1 2) Pluto's orbit has a lower inclination to the ecliptic than any planet. Answer: FALSE Diff: 1 Section Ref.: 4.1 3) One characteristic of the terrestrial planets is their extensive moon systems. Answer: FALSE Diff: 1 Section Ref.: 4.1 4) All the planet's orbits are evenly spaced. Answer: FALSE Diff: 1 Section Ref.: 4.1 5) Earth is nearly twice as large as Venus. Answer: FALSE Diff: 1 Section Ref.: 4.1 6) All the planets revolve around the Sun in the same direction, except for Venus and Uranus. Answer: FALSE Diff: 2 Section Ref.: 4.1 7) All the planets orbit the Sun in exactly the same plane as the Earth. Answer: FALSE Diff: 2 Section Ref.: 4.1 8) The two smallest planets, Mercury and Pluto, have no moons. Answer: FALSE Diff: 2 Section Ref.: 4.1 9) All four jovian planets are thought to have cores larger than Earth. Answer: TRUE Diff: 2 Section Ref.: 4.1 1

10) All jovian planets have rings around their equators and at least eight moons. Answer: TRUE Diff: 2 Section Ref.: 4.1 11) Pluto is more similar to the jovian planet's icy moons than to any of the other planets. Answer: TRUE Diff: 2 Section Ref.: 4.1 12) Due to their great masses, all four jovian worlds are much denser than the Earth. Answer: FALSE Diff: 2 Section Ref.: 4.1 13) A Kuiper Belt object was discovered that may be larger than Pluto. Answer: TRUE Diff: 1 Section Ref.: 4.2 14) Barringer Crater in Arizona is an example of a meteorite impact. Answer: TRUE Diff: 1 Section Ref.: 4.2 15) Most astronomers now believe the demise of the dinosaurs 65 million years ago was caused by a large asteroid impacting the Yucatan peninsula area. Answer: TRUE Diff: 1 Section Ref.: 4.2 16) Meteor showers are the result of collisions between asteroids. Answer: FALSE Diff: 1 Section Ref.: 4.2 17) Carbonaceous asteroids contain fragile organic molecules. Answer: TRUE Diff: 2 Section Ref.: 4.2 18) Many astronomers now regard Pluto as just one of the largest of the thousands of Kuiper Belt bodies found beyond Neptune. Answer: TRUE Diff: 2 Section Ref.: 4.2 2

19) Cometary dust tails lag behind the bluish ion tails as the comet rounds the Sun. Answer: TRUE Diff: 2 Section Ref.: 4.2 20) Comets are not actually members of the solar system, but have been captured by the Sun. Answer: FALSE Diff: 2 Section Ref.: 4.2 21) The Oort Cloud lies closer to the Sun than the Kuiper Belt. Answer: FALSE Diff: 2 Section Ref.: 4.2 22) Researchers estimate that there is more total mass in the Kuiper Belt than in the asteroid belt. Answer: TRUE Diff: 2 Section Ref.: 4.2 23) Some meteorites are believed to have come from Mars and the Moon. Answer: TRUE Diff: 3 Section Ref.: 4.2 24) As a rotating gas cloud contracts, it spins faster. Answer: TRUE Diff: 1 Section Ref.: 4.3 25) In the solar nebular theory, the dusty disk condensing around the Sun's equator became the ecliptic plane in which the planets then formed. Answer: TRUE Diff: 2 Section Ref.: 4.3 26) In addition to revolving around the Sun counter clockwise, most planets also rotate on their axis counter clockwise. Answer: TRUE Diff: 2 Section Ref.: 4.3

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27) Any successful model for the formation of the solar system must explain why the orbits of the planets have low eccentricities. Answer: TRUE Diff: 3 Section Ref.: 4.3 28) Astronomers have not yet been able to detect planets outside our solar system. Answer: FALSE Diff: 1 Section Ref.: 4.4 29) We would expect other planets beyond our own solar system to orbit the equators of their home stars, as our own planets orbit the Sun. Answer: TRUE Diff: 2 Section Ref.: 4.4 30) In some cases, we have seen extrasolar planets pass in front of their stars. Answer: TRUE Diff: 2 Section Ref.: 4.4 31) No stars have yet been observed that have more than one exoplanet. Answer: FALSE Diff: 1 Section Ref.: 4.4 32) The Kepler spacecraft has already identified thousands of exoplanet candidates. Answer: TRUE Diff: 1 Section Ref.: 4.4 33) The fact that we don't see very many Earthlike planets in orbit around other stars is an indication that Earthlike planets are rare. Answer: FALSE Diff: 2 Section Ref.: 4.4 34) Density is defined as A) mass per unit volume. B) weight per square inch. C) size divided by weight. D) mass times weight. E) weight divided by the planet's radius. Answer: A Diff: 1 Section Ref.: 4.1 4

35) Which of the following are the jovian planets? A) Jupiter, Saturn, Uranus, Neptune, and Pluto B) only Jupiter C) only Jupiter and Saturn D) Jupiter, Saturn, Uranus, and Neptune only E) everything past Mars and the asteroid belt Answer: D Diff: 1 Section Ref.: 4.1 36) Which planet by itself contains the majority of mass of all the planets? A) Jupiter B) Saturn C) the Earth D) Venus E) Uranus Answer: A Diff: 1 Section Ref.: 4.1 37) Planetary orbits A) are evenly spaced throughout the solar system. B) are highly inclined to the ecliptic. C) are almost circular, with low eccentricities. D) have the Sun at their exact center. E) are spaced more closely together as they get further from the Sun. Answer: C Diff: 2 Section Ref.: 4.1 38) Which of the following is not icy in composition? A) comet nuclei B) Kuiper Belt Objects C) the polar cap of Mars D) asteroids E) most jovian satellites Answer: D Diff: 2 Section Ref.: 4.1

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39) What is true about solar system densities? A) The denser planets lie closer to the Sun. B) In differentiated bodies, the denser materials lie near their surfaces. C) The asteroids all have about the same density. D) Saturn has the same density as water. E) Planetary density increases with increasing distance from the Sun. Answer: A Diff: 2 Section Ref.: 4.1 40) The jovian planets A) all lie less than 5 AU from the Sun. B) all have rings around their equators. C) all spin slower than the Earth. D) have satellite systems with less than 4 moons. E) are all much more dense than any of the terrestrial planets. Answer: B Diff: 3 Section Ref.: 4.1 41) The largest asteroid, and probably the only one to be a spherical "world" is A) Eros. B) Ida. C) Vesta. D) Ceres. E) Gaspra. Answer: D Diff: 1 Section Ref.: 4.2 42) The Kuiper Belt is found where in the solar system? A) beyond the orbit of Neptune B) among the orbits of the terrestrial planets C) between the orbits of Mars and Jupiter D) between the orbits of Jupiter and Uranus E) sixty degrees ahead or behind Jupiter Answer: A Diff: 1 Section Ref.: 4.2

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43) The tail of a comet always points A) toward the Sun and disappears at perihelion. B) toward Earth and never varies. C) away from the Sun and disappears at perihelion. D) away from the Sun and becomes longest and brightest at perihelion. E) in the direction of the comet's motion. Answer: D Diff: 1 Section Ref.: 4.2 44) The Oort Cloud is believed to be A) a flattened belt of cometary nuclei just beyond the orbit of Neptune. B) the circular disk of gas around the Sun's equator from which the planets formed. C) a grouping of asteroids and meteoroids between the orbits of Mars and Jupiter. D) a spherical cloud of cometary nuclei far beyond the Kuiper Belt. E) the great nebula found just below the belt stars of Orion. Answer: D Diff: 1 Section Ref.: 4.2 45) Which of the following does not fall into the category of interplanetary debris? A) comets B) meteoroids C) rings around the jovian planets. D) Trojan asteroids E) Kuiper Belt bodies Answer: C Diff: 2 Section Ref.: 4.2 46) Which of the following have an icy composition? A) most asteroids B) meteoroids C) comets D) the surface of Mars E) meteorites and most asteroids Answer: C Diff: 2 Section Ref.: 4.2

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47) The Trojan asteroids are found A) orbiting around the Kuiper Belt body Hector. B) with the others, between Mars and Jupiter; their red color gives them their name. C) sixty degrees ahead or behind Jupiter, sharing its orbit about the Sun. D) beyond Neptune, with orbits similar to Pluto's. E) closer on average to the Sun than is the Earth. Answer: C Diff: 2 Section Ref.: 4.2 48) The most distant objects in our solar system are A) in the Kuiper Belt. B) the jovians. C) in the Oort Cloud. D) short period comets. E) the Trojan asteroids. Answer: C Diff: 2 Section Ref.: 4.2 49) The first spacecraft to land on the surface of an asteroid was named A) Stardust. B) Giotto. C) Galileo. D) NEAR. E) Dawn. Answer: D Diff: 2 Section Ref.: 4.2 50) Which statement about asteroids is not true? A) They vary considerably in composition, reflectivity, and size. B) Most stay between the orbits of Mars and Jupiter. C) Some have satellites of their own. D) Their images become blurry due to outgassing as the Sun heats them up. E) Earthgrazers can cross not only our orbit, but even those of Venus and Mercury. Answer: D Diff: 2 Section Ref.: 4.2

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51) The most detailed look we've had of an asteroid comes from A) spacecraft sent to an asteroid. B) ground based optical images. C) Earth orbital X-ray images. D) ground based radar images. E) high-altitude UV spectroscopy. Answer: A Diff: 2 Section Ref.: 4.2 52) Before it arrived in orbit about Eros, the NEAR spacecraft visited A) Venus. B) the Moon. C) Mars. D) the asteroid Mathilde. E) the asteroid Gaspra. Answer: D Diff: 2 Section Ref.: 4.2 53) In July 2011, the Dawn probe entered orbit around A) the asteroid Ceres. B) the asteroid Vesta. C) the comet Wild. D) the asteroid Ida. E) the asteroid Gaspra. Answer: B Diff: 2 Section Ref.: 4.2 54) Relative to the comet, the direction of the ion tail tells us A) where the ecliptic is. B) the direction of the Sun. C) the velocity of the comet. D) the direction the comet is traveling. E) where the comet came from. Answer: B Diff: 2 Section Ref.: 4.2

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55) Iron meteorites are believed to come from A) the core of a differentiated asteroid, now broken up. B) the crust of a differentiated asteroid, now broken up. C) a broken up cometary nucleus. D) debris from the Kuiper Belt. E) interstellar space. Answer: A Diff: 2 Section Ref.: 4.2 56) Meteor showers are A) usually annual events, as the orbits again intersect. B) caused by the Earth passing near the orbit of an Earthgrazing asteroid. C) caused by the Earth passing near the orbit of an old short-period comet. D) Both A and B are correct. E) Both A and C are correct. Answer: E Diff: 2 Section Ref.: 4.2 57) Meteorites are important because A) they contain pristine material from the solar nebula. B) large ones may cause mass extinctions. C) some come from the Moon and Mars, as well as the asteroid belt. D) All of the above are true. E) None of the above are true. Answer: D Diff: 2 Section Ref.: 4.2 58) A meteor is A) a chunk of space debris that has struck the ground. B) a streak of light in the atmosphere. C) an icy body with a long tail extending from it. D) a chunk of space debris orbiting the Earth. E) an irregularly shaped body, mostly found orbiting between Mars and Jupiter. Answer: B Diff: 2 Section Ref.: 4.2

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59) A meteorite is A) a chunk of space debris that has struck the ground. B) a streak of light in the atmosphere. C) an icy body with a long tail extending from it. D) a chunk of space debris orbiting the Earth. E) an irregularly shaped body, mostly found orbiting between Mars and Jupiter. Answer: A Diff: 2 Section Ref.: 4.2 60) Long-period comets are believed to originally come from A) the asteroid belt. B) the Kuiper belt. C) the Oort cloud. D) the satellite system of Jupiter. E) the interstellar medium. Answer: C Diff: 2 Section Ref.: 4.2 61) The orbits of most comets A) are like the planets, fairly circular and in the ecliptic plane. B) lie almost entirely beyond the orbit of Neptune. C) have perihelions within the orbits of Mercury. D) go no farther out than Pluto, then return to the sun again. E) are shorter than the 76-year period for Comet Halley. Answer: B Diff: 2 Section Ref.: 4.2 62) Objects in the Kuiper belt A) are in random orbits at all inclinations to the ecliptic. B) lie beyond the orbit of Neptune, and close to the ecliptic. C) are the sources of long-period comets. D) are dense, like the iron meteorites. E) lie beyond the orbit of Neptune and perpendicular to the ecliptic. Answer: B Diff: 2 Section Ref.: 4.2

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63) Which of these bodies are most likely to break up over time? A) asteroids in the main belt B) jovian satellites C) comet nuclei D) Kuiper Belt bodies E) Trojan asteroids Answer: C Diff: 2 Section Ref.: 4.2 64) The Manicouagan reservoir near Quebec is an example of A) a volcanic event. B) cometary debris. C) Earth's interaction with a comet's dust tail. D) a large meteorite impact. E) a micrometeorite impact. Answer: D Diff: 2 Section Ref.: 4.2 65) The nucleus of a comet is typically A) a few meters in diameter. B) very durable, made of iron. C) a few kilometers in size, and very low in density. D) a few hundred kilometers across, and bright, shiny white from its ices. E) located between the orbits of Mars and Jupiter. Answer: C Diff: 2 Section Ref.: 4.2 66) Before it arrived in orbit about Jupiter, the Galileo spacecraft flew past A) Comet Halley. B) Mars. C) Saturn. D) the asteroid Gaspra. E) the asteroid Ceres. Answer: D Diff: 3 Section Ref.: 4.2

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67) If a comet's ion tail is pointing perpendicular to its direction of travel, the comet is A) close to or at perihelion. B) close to or at aphelion. C) moving closer to the Sun. D) moving away from the Sun. E) A comet's tail never points perpendicular to its motion. Answer: A Diff: 3 Section Ref.: 4.2 68) As the solar nebula contracts, it A) flattens out into the ecliptic plane around the Sun's poles. B) spins faster due to conservation of angular momentum. C) cools due to condensation. D) loses angular momentum. E) reverses its direction of rotation. Answer: B Diff: 2 Section Ref.: 4.3 69) In terms of composition A) all planets condensed from the same nebula, and have similar compositions. B) the jovian planets are more like the Sun than are the terrestrials. C) the terrestrials are more like the Sun, since they formed close to it. D) the Sun is unique, made of nothing but hydrogen and helium. E) the jovian planets are made only of ice, and the terrestrials only of rock. Answer: B Diff: 2 Section Ref.: 4.3 70) According to the Solar Nebula theory, planets A) should be randomly oriented to their star's equator. B) will revolve opposite the star's rotation. C) should be a common result of star formation. D) should be extremely rare. E) should orbit perpendicular to their star's equator. Answer: C Diff: 2 Section Ref.: 4.3

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71) As a rotating gas cloud contracts, it spins A) faster due to an increase in angular momentum. B) slower due to a decrease in angular momentum. C) at a constant rate. D) faster due to conservation of angular momentum. E) slower due to conservation of angular momentum. Answer: D Diff: 3 Section Ref.: 4.3 72) The larger terrestrial planets have surface features that tend to be A) older. B) younger. C) more cratered. D) more icy. E) more rocky. Answer: B Diff: 3 Section Ref.: 4.3 73) So far, beyond the solar system the extrasolar planets found have been mostly A) large jovians orbiting solar-type stars about where our jovians are found. B) large jovians very close to their star. C) terrestrials very close to their star, and transiting its disk. D) terrestrials with very elongated, distant orbits like comets. E) brown dwarfs much more massive than Jupiter. Answer: B Diff: 2 Section Ref.: 4.4 74) Most of the extrasolar planets found so far were detected by A) noting the drop in the star's light as the planet transits its disk. B) imaging them with the HST in the infrared, where they are easier to stop. C) noting the Doppler shifts of the star as the planet orbits it from side to side. D) receiving radio transmissions from them, much like Jupiter emits. E) detecting the oxygen in their atmospheres spectroscopically. Answer: C Diff: 2 Section Ref.: 4.4

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75) Which statement about extrasolar planets found to date is true? A) All are terrestrials, comparable in size to Earth. B) Few are found by Doppler shifts of their stars, due to their gravity. C) All lie more than 2 AU from their star. D) Most have orbital periods of more than a year. E) Some are so close to their stars that their periods are just a few days. Answer: E Diff: 2 Section Ref.: 4.4 76) The number of confirmed extrasolar planets A) is about 600, and is not expected to rise very much. B) has been decreasing as some observations thought to be planets have been disproven. C) is about 800, and is rising slowly, as observations are quite difficult. D) was about 800 at the time of publication but is rising rapidly due to new observations by the Kepler spacecraft. E) is zero; there are observations thought to be of extrasolar planets but none has yet been confirmed. Answer: D Diff: 2 Section Ref.: 4.4 77) Planetary transits of exoplanets are rare because A) most exoplanets are smaller than Pluto. B) most extrasolar systems are not seen edge-on. C) our telescopes are not powerful enough to detect them. D) most stars are too bright for us to detect a planetary transit. E) the Earth's atmosphere interferes with our observations of transits. Answer: B Diff: 2 Section Ref.: 4.4 78) Exoplanets known as super-Earths A) have masses comparable to that of Jupiter. B) have masses comparable to that of Neptune. C) have masses 2-10 times that of Earth. D) orbit extremely massive stars. E) have yet to be observed. Answer: C Diff: 2 Section Ref.: 4.4 79) All planets lie in orbits close to the ________ plane. Answer: ecliptic Diff: 1 Section Ref.: 4.1 15

80) The ________ planets are large bodies in the outer solar system with compositions like the Sun's. Answer: jovian Diff: 1 Section Ref.: 4.1 81) A body in orbit about a planet is a ________. Answer: moon or satellite Diff: 1 Section Ref.: 4.1 82) All ________ planets have rings around their equators Answer: jovian Diff: 1 Section Ref.: 4.1 83) ________ is the only planet with a mean density less than water. Answer: Saturn Diff: 1 Section Ref.: 4.1 84) The terrestrial planets have mantles of ________ materials and iron rich cores. Answer: silicates or rocky Diff: 1 Section Ref.: 4.1 85) The only planet with no atmosphere of consequence is ________. Answer: Mercury Diff: 2 Section Ref.: 4.1 86) A rocky body between the orbits of Mars and Jupiter is a(n) ________. Answer: asteroid Diff: 1 Section Ref.: 4.2 87) In composition, the ________ planets have rocky materials like the asteroids. Answer: terrestrial Diff: 1 Section Ref.: 4.2 88) The ________ Belt bodies orbit beyond Neptune, but like the planets stay close to the ecliptic plane and in fairly circular orbits. Answer: Kuiper Diff: 1 Section Ref.: 4.2 16

89) The ________ is a vast, spherical array of long period comet nuclei far beyond the orbit of Neptune. Answer: Oort Cloud Diff: 1 Section Ref.: 4.2 90) Comet orbits all have ________ eccentricity compared to the asteroids. Answer: high Diff: 1 Section Ref.: 4.2 91) Most asteroid orbits lie between those of Mars and ________. Answer: Jupiter Diff: 1 Section Ref.: 4.2 92) A solid body from the outer solar system that arrives intact on the Earth's surface is called a ________. Answer: meteorite Diff: 1 Section Ref.: 4.2 93) Streaks of light made when small debris hits our atmosphere are called ________. Answer: meteors Diff: 1 Section Ref.: 4.2 94) The curved, yellow ________ tail lags behind the blue tail as the comet rounds the Sun. Answer: dust Diff: 1 Section Ref.: 4.2 95) While Kuiper Belt bodies are often larger than any asteroid, we think their density will be lower due to presence of a lot of ________. Answer: ice Diff: 1 Section Ref.: 4.2 96) The ________ is the spherical outgassing as a comet nucleus is heated by the Sun. Answer: coma Diff: 1 Section Ref.: 4.2

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97) The asteroids moving in the orbit of Jupiter, but 60 degrees ahead or behind it, are called the ________. Answer: Trojans or Trojan asteroids. Diff: 2 Section Ref.: 4.2 98) The NEAR spacecraft actually landed on the asteroid ________ in February 2001. Answer: Eros Diff...