1. Universe Tenth Edition Chapter 8 Comparative Planetology II: The Origin of Our Solar System Roger Freedman Robert Geller William Kaufmann III Clicker Questions

2. All the planets orbit the Sun in the same direction. This is strong evidence that A.the solar system formed from a rotating cloud of gas that collapsed to form the Sun and planets. B.the planets were formed elsewhere in the Galaxy and were later captured by the Sun. C.after the planets formed, collisions between them eventually caused them all to move in the same direction. D.the solar system resulted from the collision of two medium-sized stars. E.None of the above. We do not have any idea yet how our solar system may have formed. Q8.1

3. All the planets orbit the Sun in the same direction. This is strong evidence that A.the solar system formed from a rotating cloud of gas that collapsed to form the Sun and planets. B.the planets were formed elsewhere in the Galaxy and were later captured by the Sun. C.after the planets formed, collisions between them eventually caused them all to move in the same direction. D.the solar system resulted from the collision of two medium-sized stars. E.None of the above. We do not have any idea yet how our solar system may have formed. A8.1

4. As the solar nebula contracted, much of its material formed into a disk. This happened because A.the nebula was cool and so everything fell toward the center very rapidly. B.the nebula was spinning. C.the nebula always had a disk shape. D.Kepler ’ s laws did not hold in the early solar system. E.the nebula was not spinning. Q8.2

5. As the solar nebula contracted, much of its material formed into a disk. This happened because A.the nebula was cool and so everything fell toward the center very rapidly. B.the nebula was spinning. C.the nebula always had a disk shape. D.Kepler ’ s laws did not hold in the early solar system. E.the nebula was not spinning. A8.2

6. Protoplanets are thought to coalesce from planetesimals about 1 km in diameter. Why do these planetesimals stick together when they collide? A.Gravitational attraction between the planetesimals. B.The planetesimals are electrically charged, and electric forces make them attract each other. C.Chemical bonds hold the planetesimals together. D.Both B and C. E.A sticky surface material causes them to adhere. Q8.3

7. Protoplanets are thought to coalesce from planetesimals about 1 km in diameter. Why do these planetesimals stick together when they collide? A.Gravitational attraction between the planetesimals. B.The planetesimals are electrically charged, and electric forces make them attract each other. C.Chemical bonds hold the planetesimals together. D.Both B and C. E.A sticky surface material causes them to adhere. A8.3

8. Protoplanets are thought to coalesce from planetesimals about 1 km in diameter. These planetesimals in turn form from much smaller particles. Why do these smaller particles stick together when they collide? A.Gravitational attraction between the small particles. B.The particles are electrically charged, and electric forces make them attract each other. C.Chemical bonds hold the particles together. D.Both B and C. E.A sticky surface material causes them to adhere. Q8.4

9. Protoplanets are thought to coalesce from planetesimals about 1 km in diameter. These planetesimals in turn form from much smaller particles. Why do these smaller particles stick together when they collide? A.Gravitational attraction between the small particles. B.The particles are electrically charged, and electric forces make them attract each other. C.Chemical bonds hold the particles together. D.Both B and C. E.A sticky surface material causes them to adhere. A8.4

10. Is there any debris left over from the small particles that formed planetesimals, which in turn coalesced into the planets? A.No, all the material was used up in forming the planets. B.Yes, there is debris left over in the form of asteroids and comets. C.No, the material left over was all burned up in the Sun. D.Yes, but we cannot see it because of its small size. E.No, the material left over was all ejected from the solar system by Jupiter and Saturn. Q8.5

11. Is there any debris left over from the small particles that formed planetesimals, which in turn coalesced into the planets? A.No, all the material was used up in forming the planets. B.Yes, there is debris left over in the form of asteroids and comets. C.No, the material left over was all burned up in the Sun. D.Yes, but we cannot see it because of its small size. E.No, the material left over was all ejected from the solar system by Jupiter and Saturn. A8.5

12. The terrestrial planets formed close to the Sun because A.when the solar nebula originally formed, most of the silicates in the nebula were toward the nebula ’ s center. B.silicates could only condense close to the Sun. C.it was so hot in the inner solar nebula that any protoplanets forming there could not capture significant amounts of hydrogen or helium. D.there was no hydrogen or helium in the inner solar nebula where these planets formed. E.the Sun ’ s gravitational pull is greater there. Q8.6

13. The terrestrial planets formed close to the Sun because A.when the solar nebula originally formed, most of the silicates in the nebula were toward the nebula ’ s center. B.silicates could only condense close to the Sun. C.it was so hot in the inner solar nebula that any protoplanets forming there could not capture significant amounts of hydrogen or helium. D.there was no hydrogen or helium in the inner solar nebula where these planets formed. E.the Sun ’ s gravitational pull is greater there. A8.6

14. The Jovian planets formed in the outer solar system far from the Sun because A.this was where most of the hydrogen and helium in the solar nebula was located. B.there were no silicates in the outer solar system. C.it was cool enough for the protoplanets forming there to capture significant amounts of hydrogen or helium. D.there was no hydrogen or helium in the inner solar nebula to form Jovian planets. E.the smaller mass of hydrogen and helium allowed them to be gaseous. Q8.7

15. The Jovian planets formed in the outer solar system far from the Sun because A.this was where most of the hydrogen and helium in the solar nebula was located. B.there were no silicates in the outer solar system. C.it was cool enough for the protoplanets forming there to capture significant amounts of hydrogen or helium. D.there was no hydrogen or helium in the inner solar nebula to form Jovian planets. E.the smaller mass of hydrogen and helium allowed them to be gaseous. A8.7

16. Which aspect of the early solar nebula controlled the early evolution and place of formation of the terrestrial and the Jovian planets? A.The rotation of the nebula. B.The distribution of hydrogen in the nebula. C.The distribution of silicates in the nebula. D.The temperature distribution within the nebula. E.The mass of the Sun. Q8.8

17. Which aspect of the early solar nebula controlled the early evolution and place of formation of the terrestrial and the Jovian planets? A.The rotation of the nebula. B.The distribution of hydrogen in the nebula. C.The distribution of silicates in the nebula. D.The temperature distribution within the nebula. E.The mass of the Sun. A8.8

18. A telescope with excellent resolution is used to monitor a protoplanetary disk about the same size as the one that became our solar system. Assume the disk has just formed. How long would we have to monitor the disk until we actually see planets? A.About 10 years B.About 1000 years C.About 100,000 years D.About 1,000,000 (1 million) years E.Tens or hundreds of millions of years Q8.9

19. A telescope with excellent resolution is used to monitor a protoplanetary disk about the same size as the one that became our solar system. Assume the disk has just formed. How long would we have to monitor the disk until we actually see planets? A.About 10 years B.About 1000 years C.About 100,000 years D.About 1,000,000 (1 million) years E.Tens or hundreds of millions of years A8.9

20. Extrasolar planets are not seen directly. An observation that has been used to indirectly show they exist is A.the regular back and forth movement of the position of spectral lines of the parent stars. B.the change in luminosity of the parent star when a planet moves in front of it. C.detection of methane, which can only exist in planetary atmospheres. D.detection of faint oxygen lines, which can only exist in planetary atmospheres. E.both A and B. Q8.10

21. Extrasolar planets are not seen directly. An observation that has been used to indirectly show they exist is A.the regular back and forth movement of the position of spectral lines of the parent stars. B.the change in luminosity of the parent star when a planet moves in front of it. C.detection of methane, which can only exist in planetary atmospheres. D.detection of faint oxygen lines, which can only exist in planetary atmospheres. E.both A and B. A8.10

22. The majority of the extrasolar planets discovered so far are A.distributed according to mass and distance from their parent star in a similar way to the planets in our solar system. B.very large, and there does not appear to be a particular pattern in their distance from their parent star. C.Earth-sized, and there does not appear to be a particular pattern in their distance from their parent star. D.much larger than Earth and known to be made up of large amounts of hydrogen and helium. E.None of the above. Q8.11

23. The majority of the extrasolar planets discovered so far are A.distributed according to mass and distance from their parent star in a similar way to the planets in our solar system. B.very large, and there does not appear to be a particular pattern in their distance from their parent star. C.Earth-sized, and there does not appear to be a particular pattern in their distance from their parent star. D.much larger than Earth and known to be made up of large amounts of hydrogen and helium. E.None of the above. A8.11

24. The extrasolar planets discovered so far tend to have a much higher mass than Earth, and many of them are Jupiter ’ s size. The reason for this is that A.extra-solar Jupiter-sized planets are much more abundant than Earth-sized planets. B.astronomers are only interested in looking for really large planets. C.the methods of planet detection developed so far work best for very large planets. D.extra-solar Jupiter-sized planets are all really cold, and cold planets are easier to detect. E.extra-solar Jupiter-sized planets are all really hot, and hot planets are easier to detect. Q8.12

25. The extrasolar planets discovered so far tend to have a much higher mass than Earth, and many of them are Jupiter ’ s size. The reason for this is that A.extra-solar Jupiter-sized planets are much more abundant than Earth-sized planets. B.astronomers are only interested in looking for really large planets. C.the methods of planet detection developed so far work best for very large planets. D.extra-solar Jupiter-sized planets are all really cold, and cold planets are easier to detect. E.extra-solar Jupiter-sized planets are all really hot, and hot planets are easier to detect. A8.12