Chapter 4 - Group Homework Name___________________________________ MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Density is defined as 1) A) mass times weight. B) mass per unit volume. C) weight divided by the planet's radius. D) weight per square inch. E) size divided by weight. 2) Which of the following are the jovian planets? 2) A) only Jupiter B) Jupiter, Saturn, Uranus, and Neptune only C) Jupiter, Saturn, Uranus, Neptune, and Pluto D) everything past Mars and the asteroid belt E) only Jupiter and Saturn 3) Which planet by itself contains the majority of mass of all the planets? 3) A) Jupiter B) Uranus C) the Earth D) Venus E) Saturn 4) Planetary orbits 4) A) are highly inclined to the ecliptic. B) are almost circular, with low eccentricities. C) have the Sun at their exact center. D) are evenly spaced throughout the solar system. E) are spaced more closely together as they get further from the Sun. 5) Based on its orbit, which planet behaves the least like the others? 5) A) Pluto B) Mars C) Venus D) Uranus E) Mercury 6) Which of the following is not icy in composition? 6) A) Kuiper Belt Objects B) comet nuclei C) the polar cap of Mars D) most jovian satellites E) asteroids 7) What is true about solar system densities? 7) A) The asteroids all have about the same density. B) Planetary density increases with increasing distance from the Sun. C) In differentiated bodies, the denser materials lie near their surfaces. D) The denser planets lie closer to the Sun. E) Saturn has the same density as water. 8) The jovian planets 8) A) have satellite systems with less than 4 moons. B) are all much more dense than any of the terrestrial planets. C) all lie less than 5 AU from the Sun. D) all spin slower than the Earth. E) all have rings around their equators. 1 9) The largest asteroid, and probably the only one to be a spherical "world" is 9) A) Vesta. B) Ceres. C) Gaspra. D) Ida. E) Eros. 10) How much advance warning did we have of the close approach of asteroid 2002 MN in June 10) 2002? A) None; it was found three days after its closest approach. B) four hours C) three days D) several weeks E) six years 11) The Kuiper Belt is found where in the solar system? 11) A) beyond the orbit of Neptune B) among the orbits of the terrestrial planets C) between the orbits of Jupiter and Uranus D) sixty degrees ahead or behind Jupiter E) between the orbits of Mars and Jupiter 12) The tail of a comet always points 12) A) toward Earth and never varies. B) away from the Sun and disappears at perihelion. C) away from the Sun and becomes longest and brightest at perihelion. D) in the direction of the comet's motion. E) toward the Sun and disappears at perihelion. 13) The Oort Cloud is believed to be 13) A) a flattened belt of cometary nuclei just beyond the orbit of Neptune. B) the great nebula found just below the belt stars of Orion. C) a spherical cloud of cometary nuclei far beyond the Kuiper Belt. D) the circular disk of gas around the Sun's equator from which the planets formed. E) a grouping of asteroids and meteoroids between the orbits of Mars and Jupiter. 14) Which of the following does not fall into the category of interplanetary debris? 14) A) Kuiper Belt bodies B) meteoroids C) Trojan asteroids D) comets E) rings around the jovian planets. 15) Which of the following have an icy composition? 15) A) the surface of Mars B) most asteroids C) meteorites and most asteroids D) meteoroids E) comets 16) The Trojan asteroids are found 16) A) sixty degrees ahead or behind Jupiter, sharing its orbit about the Sun. B) orbiting around the Kuiper Belt body Hector. C) closer on average to the Sun than is the Earth. D) with the others, between Mars and Jupiter; their red color gives them their name. E) beyond Neptune, with orbits similar to Pluto's. 2 17) The most distant objects in our solar system are 17) A) short period comets. B) in the Kuiper Belt. C) the Trojan asteroids. D) the jovians. E) in the Oort Cloud. 18) The first spacecraft to land on the surface of an asteroid was named 18) A) NEAR. B) Giotto. C) Contour. D) Stardust. E) Galileo. 19) Which statement about asteroids is not true? 19) A) Some have satellites of their own. B) Earthgrazers can cross not only our orbit, but even those of Venus and Mercury. C) Most stay between the orbits of Mars and Jupiter. D) They vary considerably in composition, reflectivity, and size. E) Their images become blurry due to outgassing as the Sun heats them up. 20) The most detailed look we've had of an asteroid comes from 20) A) ground based optical images. B) ground based radar images. C) high-altitude UV spectroscopy. D) spacecraft sent to an asteroid. E) Earth orbital X-ray images. 21) Before it arrived in orbit about Eros, the NEAR spacecraft visited 21) A) Venus. B) the Moon. C) the asteroid Mithilde. D) the asteroid Gaspra. E) Mars. 22) Relative to the comet, the direction of the ion tail tells us 22) A) the velocity of the comet. B) where the comet came from. C) the direction of the Sun. D) the direction the comet is traveling. E) where the ecliptic is. 23) Meteor showers are 23) 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. 24) Meteorites are important because 24) A) they contain pristine material from the solar nebula. B) some come from the Moon and Mars, as well as the asteroid belt. C) large ones may cause mass extinctions. D) All of the above are true. E) None of the above are true. 3 25) A meteor is 25) A) an irregularly shaped body, mostly found orbiting between Mars and Jupiter. B) a streak of light in the atmosphere. C) a chunk of space debris that has struck the ground. D) an icy body with a long tail extending from it. E) a chunk of space debris orbiting the Earth. 26) A meteorite is 26) A) a chunk of space debris that has struck the ground. B) a chunk of space debris orbiting the Earth. C) a streak of light in the atmosphere. D) an irregularly shaped body, mostly found orbiting between Mars and Jupiter. E) an icy body with a long tail extending from it. 27) Long-period comets are believed to originally come from 27) A) the Oort cloud. B) the satellite system of Jupiter. C) the interstellar medium. D) the asteroid belt. E) the Kuiper belt. 28) Objects in the Kuiper belt 28) A) lie beyond the orbit of Neptune, and close to the ecliptic. B) are in random orbits at all inclinations 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. 29) Which of these bodies are most likely to break up over time? 29) A) Trojan asteroids B) jovian satellites C) comet nuclei D) Kuiper Belt bodies E) asteroids in the main belt 30) The Manicouagan reservoir near Quebec is an example of 30) A) a micrometeorite impact. B) a volcanic event. C) a large meteorite impact. D) Earth's interaction with a comet's dust tail. E) cometary debris. 31) The nucleus of a comet is typically 31) A) a few kilometers in size, and very low in density. B) very durable, made of iron. C) a few meters in diameter. D) located between the orbits of Mars and Jupiter. E) a few hundred kilometers across, and bright, shiny white from its ices. 4 32) Before it arrived in orbit about Jupiter, the Galileo spacecraft flew past 32) A) the asteroid Gaspra. B) Comet Halley. C) Mars. D) Saturn. E) the asteroid Ceres. 33) If a comet's ion tail is pointing perpendicular to its direction of travel, the comet is 33) A) moving away from the Sun. B) close to or at aphelion. C) close to or at perihelion. D) moving closer to the Sun. E) A comet's tail never points perpendicular to its motion. 34) As the solar nebula contracts, it 34) A) flattens out into the ecliptic plane around the Sun's poles. B) spins faster due to conservation of angular momentum. C) reverses its direction of rotation. D) loses angular momentum. E) cools due to condensation. 35) In terms of composition 35) A) the jovian planets are made only of ice, and the terrestrials only of rock. B) all planets condensed from the same nebula, and have similar compositions. C) the terrestrials are more like the Sun, since they formed close to it. D) the jovian planets are more like the Sun than are the terrestrials. E) the Sun is unique, made of nothing but hydrogen and helium. 36) According to the Solar Nebula theory, planets 36) A) should be a common result of star formation. B) should be randomly oriented to their star's equator. C) should be extremely rare. D) should orbit perpendicular to their star's equator.