sas astronomi

64
Chapter 14 The Stars: How much longer can the Sun sustain life on Earth? 1. The energy source of stars is primarily associated with a. the reactions of atoms in the star corona. b. the reactions of nuclei in the star core. c. the reactions of atoms in the outer regions of the star. d. burning of elements until they become radioactive. e. burning of elements heavier than lead. Ans: b Link To: The Anatomy of Stars Difficulty Level: Easy 2. If scientists located a Dyson Sphere, they would find a. something made from a dismantled planet. b. a planet in orbit around our closest star. c. an energy source built to surround a planet. d. an object at the core of the Sun. e. the corona during a total eclipse. Ans: a Link To: The Anatomy of Stars Difficulty Level: Easy 3. The solar wind a. extends into space as far as Mercury. b. consists of hydrogen and carbon particles. 243

Upload: muhammad-risfan-badrus-salam

Post on 22-Nov-2014

142 views

Category:

Documents


6 download

TRANSCRIPT

Page 1: SAS Astronomi

Chapter 14The Stars:

How much longer can the Sun sustain life on Earth?1. The energy source of stars is primarily associated witha. the reactions of atoms in the star corona.b. the reactions of nuclei in the star core.c. the reactions of atoms in the outer regions of the star.d. burning of elements until they become radioactive.e. burning of elements heavier than lead.

Ans: bLink To: The Anatomy of StarsDifficulty Level: Easy

2. If scientists located a Dyson Sphere, they would finda. something made from a dismantled planet.b. a planet in orbit around our closest star.c. an energy source built to surround a planet.d. an object at the core of the Sun.e. the corona during a total eclipse.

Ans: aLink To: The Anatomy of StarsDifficulty Level: Easy

3. The solar winda. extends into space as far as Mercury.b. consists of hydrogen and carbon particles.c. is a part of the Sun’s atmospheric circulation.d. affects the magnetic fields of planets.e. is another term for the Sun’s chromosphere.

Ans: dLink To: The Anatomy of StarsDifficulty Level: Easy4. Which of the following can be said about large stars?a. Large stars have a longer lifetime than smaller stars.

243

Page 2: SAS Astronomi

Chapter 15

b. Large stars have a shorter lifetime than smaller stars.c. Large star lifetime is about the same as that of smaller stars.d. The helium in the large star's core burns to produce hydrogen.e. Large stars are the source of oxygen in photosynthesis.

Ans: bLink To: The Life Cycles of StarsDifficulty Level: Easy

5. At this moment, the Sun is producing energy by burninga. plutonium.b. anthracite.c. hydrogen.d. helium.e.iron.

Ans: cLink To: The Anatomy of StarsDifficulty Level: Easy

6. The end products of fusion in the Sun's core area. helium isotopes, protons, and gamma rays.b. hydrogen isotopes, photons, and infrared rays.c. helium ions, photons, and hydrogen isotopes.d. hydrogen ions, protons, and gamma rays.e. deuterium, photons, and gamma rays.

Ans: aLink To: The Anatomy of StarsDifficulty Level: Easy

7. Approximately how long does it take the energy of the Sun to be transferred from the stellar core to the photosphere?a. one light-yearb. many thousands of years c. 24 hoursd. one monthe. eight minutes

Ans: b

244

Page 3: SAS Astronomi

Chapter 15

Link To: The Anatomy of StarsDifficulty Level: Easy

8. Which of the following affect the life of a star?a. gravitational forceb. massc. temperatured. fusion processese. all of the above

Ans: eLink To: The Life Cycles of StarsDifficulty Level: Easy

9. From what part of the electromagnetic spectrum is most of the Sun’s energy emitted?a. radio wavesb .infrared wavesc. visible light wavesd. gamma rayse. microwaves

Ans: cLink To: The Nature of StarsDifficulty Level: Easy

10. Which of the following satellite observatories could not detect the presence of a black hole?a. Compton Gamma Ray Observatory (GRO)b. Chandra X-ray Observatoryc. Hubble Space Telescope (HST)d. Space Infrared Telescope Facility (SIRTF)e. only a and b

Ans: dLink To: The Nature of StarsDifficulty Level: Medium

11. Differences in how a star appears in the sky are a function ofa. the size of the star.b. how far away the star is from Earth.

245

Page 4: SAS Astronomi

Chapter 15

c. the total energy emitted by the star.d. the star’s apparent brightness.e. all of the above

Ans: eLink To: The Variety of StarsDifficulty Level: Easy

12. The Hertzsprung-Russell diagram is a graphical technique used in astronomy to comparea. the surface temperature versus the energy output of a star.b. the star’s luminosity versus its distance from Earth.c. the absolute magnitude of the star versus the star’s relative temperature.d. the distance the Sun is from the nearest red giant.e. the location of possible solar systems in the Milky Way.

Ans: aLink To: The Life Cycles of StarsDifficulty Level: Easy

13. Where in the Milky Way galaxy would astronomers expect to find planetary systems other than our own?a. Dyson Sphereb. nebulaec. supernovasd. black holee. Cepheid stars

Ans: bLink To: The Life Cycles of StarsDifficulty Level: Easy

14. Which of the following is not an endpoint of stellar evolution?a. white dwarfb. main sequence starc. pulsard. black holee. neutron star

Ans: bLink To: The Life Cycles of Stars

246

Page 5: SAS Astronomi

Chapter 15

Difficulty Level: Easy

15. Where were the heaviest chemical elements on Earth created?a. neutron starsb. black holesc. the Sund. supernovaee. the asteroid belt

Ans: dLink To: The Life Cycles of StarsDifficulty Level: Easy

16. If you were to observe a pulsar, what would you see?a. a blinking red glowb. intermittent radio wavesc. a steady glow that oscillates among the starsd. the sudden brightening of a stare. the total eclipse of the Sun

Ans: bLink To: The Life Cycles of StarsDifficulty Level: Easy

17. What is Supernova 1987A likely to become?a. black holeb. pulsarsc. main sequence stard. Cepheid variablee. solar wind

Ans: bLink To: The Life Cycles of StarsDifficulty Level: Easy

18. If the Hubble telescope detects an intensely bright region in the sky that lasts only a few days, it has probably found evidence of aa. white dwarf.b. supernova.

247

Page 6: SAS Astronomi

Chapter 15

c. main sequence star.d. new galaxy.e. black hole.

Ans: bLink To: The Nature of StarsDifficulty Level: Easy

19. Which of the following star variables would not be in an astronomer’s data?a. wave lengthb. intensityc. soundd. positione. brightness

Ans: cLink To: The Nature of StarsDifficulty Level: Easy

20. Which of the following telescopes would have a collecting mirror?a. Chandra X-ray orbiting observatory telescope b. Hubble telescopec. Very Large Array telescope in New Mexicod. Hertzsprung-Russell telescope at Harvarde. all of the above

Ans: bLink To: The Nature of StarsDifficulty Level: Easy

21. Which of the following is among the things scientists predict for Sun's demise?a. The burning of helium will produce a carbon ash core.b. The Sun will expand until it extends past the present orbit of Venus.c. The sun will emit more energy but appear to be cool.d. At different points in its final years, the Sun will become a red giant and a white dwarf.e. All of the above are true.

Ans: eLink To: The Life Cycles of StarsDifficulty Level: Easy

248

Page 7: SAS Astronomi

Chapter 15

22. Red giants can be described asa. huge planets that are surrounded by gases.b. large stars that emit a lot of energy but have cool surfaces.c. large stars that emit a lot of energy but have glowing, hot surfaces.d. stars that are in the hydrogen-burning stage of their lives.e. large planets with glowing iron oxide surfaces.

Ans: bLink To: The Life Cycles of StarsDifficulty Level: Easy

23. The starry night sky seen from Earth is a temporary phenomenon that has lasted about 15 billion years.

Ans: TrueLink To: The Nature of StarsDifficulty Level: Easy

24. Some stars will burn forever.

Ans: FalseLink To: The Life Cycles of StarsDifficulty Level: Easy

25. The Sun's peak output of energy is within the visible spectrum.

Ans: TrueLink To: The Anatomy of StarsDifficulty Level: Easy

26. Record numbers of neutrinos from the Sun have been isolated at the solar neutrino laboratory in South Dakota.

Ans: FalseLink To: The Anatomy of Stars

249

Page 8: SAS Astronomi

Chapter 15

Difficulty Level: Easy

27. All objects with temperatures above absolute zero will radiate some form of electromagnetic waves.

Ans: TrueLink To: The Nature of StarsDifficulty Level: Easy

28. Except for visible light and radio waves, the atmosphere of the Earth is opaque to most of the electromagnetic spectrum.

Ans: TrueLink To: The Nature of StarsDifficulty Level: Easy

29. The absolute magnitude of a star is the brightness as seen from Earth, depending on the star’s distance from Earth.

Ans: FalseLink To: The Variety of StarsDifficulty Level: Easy

30. The distance to stars greater than 500 light-years away is measured using Cepheid variable stars.

Ans: TrueLink To: The Variety of StarsDifficulty Level: Easy

31. A main sequence star in the H-R diagram is in the hydrogen burning stage of its existence.

Ans: TrueLink To: The Life Cycles of StarsDifficulty Level: Easy

250

Page 9: SAS Astronomi

Chapter 15

32. A star balances the forces of gravity against the high temperature and pressure of nuclear fires in the stellar core.

Ans: TrueLink To: The Life Cycles of StarsDifficulty Level: Easy

33. The degeneracy pressure of electrons is usually measured at the earliest stage of a star’s existence.

Ans: FalseLink To: The Life Cycles of StarsDifficulty Level: Easy

34. A star will start its existence as a white dwarf and end as a red giant.

Ans: FalseLink To: The Life Cycles of StarsDifficulty Level: Easy

35. A neutron star is dense and small, compared to the Sun.

Ans: TrueLink To: The Life Cycles of StarsDifficulty Level: Easy

36. The supernova 1987A contradicted all the theories of stellar evolution proposed up to that time.

Ans: FalseLink To: The Life Cycles of StarsDifficulty Level: Easy

37. What are the two factors that affect the behavior of every star?

251

Page 10: SAS Astronomi

Chapter 15

Ans: Mass and age.Link To: The Variety of StarsDifficulty Level: Easy

38. The iron in your blood was made duringa. a chemical process that occurred during Earth's formation.b. the final moments in the life of a small star.c. fusion during our Sun's creation.d. fission reactions during the Big Bang.e. the nuclear burning of a very large star.

Ans: eLink To: The Life Cycles of StarsDifficulty Level: Medium

39. If you were describing the structure of the Sun correctly, you would say thata. ten percent of the total volume of the Sun is the core.b. the Sun’s outer region is a convection zone.c. the photosphere thins away from the Sun's surface.d. a gaseous chromosphere and corona are visible only during a solar eclipse.e. All of the above are true.

Ans: eLink To: The Anatomy of StarsDifficulty Level: Medium

40. Why do astronomers prefer orbiting telescopes over Earth-based telescopes?a. lower user costs and more research time optionsb. exciting space travel possible for observationsc. wider range of electromagnetic wavelengths detectedd. greater international cooperatione. more aesthetically pleasing

Ans: cLink To: The Nature of StarsDifficulty Level: Medium

252

Page 11: SAS Astronomi

Chapter 15

41. It is impossible to extract energy from iron by fusion or fission.

Ans: TrueLink To: The Life Cycles of StarsDifficulty Level: Medium

42. Why are new stars made of hydrogen gas?

Ans: Hydrogen gas is the simplest and the most common material in space.Link To: The Life Cycles of StarsDifficulty Level: Medium

43. What is the difference between apparent brightness and absolute brightness in star classification?

Ans: Apparent brightness is relative brightness when viewed from Earth with distant stars appearing dimmer. Absolute brightness is a measure of stellar brightness from a standard distance.Link To: The Variety of StarsDifficulty Level: Medium

44. Compare the process of hydrogen burning with helium burning in a star.

Ans: After the hydrogen fuel in the core of a star is depleted, the star will contract under the force of gravity. At the same time the temperature will rise in the core until helium is fused to form carbon. Helium burning is the final stage in a star's life that produces energy. Link To: The Anatomy of StarsDifficulty Level: Medium

45. Why do scientists believe that black holes exist, since black holes cannot be seen and none have ever been confirmed in space?

Ans: Black holes give off a particular radiation signature; objects around the black hole behave in a particular manner.Link To: The Life Cycles of StarsDifficulty Level: Medium

253

Page 12: SAS Astronomi

Chapter 15

46. From an observer’s point of view, how would the birth of a star appear different from the death of a large star (supernovae)?

Ans: These events are similar in that they both expel a shell of material although the supernova is more dramatic. These events are different in that the new star emits continuous light whereas the dying star fades to black.Link To: The Life Cycles of StarsDifficulty Level: Medium

47. From the perspective of Earth, how are neutron stars and pulsars the same and how are they different?

Ans: They are actually the same object; pulsars are only neutron stars whose poles are pointing toward the Earth.Link To: The Life Cycles of StarsDifficulty Level: Medium

48. Why are imaginary space creatures often depicted as havingeyes larger than those of Earth dwellers? Compare the “eyes” of a Venusian with the “eyes” of a Plutonian.Science fiction writers and illustrators may be enlarging

Ans: the eyes of extraterrestrials to indicate their need to collect more photons, similar in the theory explaining the large eyes of nocturnal animals. Following that logic, Venusian “eyes” would be smaller than those of the Plutonians.Link To: The Anatomy of StarsDifficulty Level: Hard

49. What is the answer to the solar neutrino problem?

Ans: Experiments before 2001, designed to measure the number of neutrinos given off by the Sun, had detected fewer neutrinos than expected. Scientists hypothesized that the ordinary electron neutrinos were converted to other types of neutrinos during theirtransit to Earth. The "lost" neutrinos were recently detected in an experiment comparing neutrino capture in pure water versus heavy water. Heavy water will only react with the electron neutrino.

254

Page 13: SAS Astronomi

Chapter 15

Pure water will react with all kinds of neutrinos. One-third of the neutrinos are ordinary electron neutrinos; two-thirds have been converted.Link To: The Anatomy of StarsDifficulty Level: Hard

50. List the events in the life of a Sun-like star in chronological order. Will the star becomes a supernova? Why or why not?

Ans: It is a part of a concentration of mass in a cloud of gas and debris. It becomes a plasma made mostly of protons and electrons. Hydrogen is burned in the star’s core.The star collapses temporarily. The star expands and becomes a red giant. The star shrinks to become a white dwarf.Link To: The Life Cycles of StarsDifficulty Level: Hard

51. What four aspects of photons are measured by astronomers and what instruments do the scientists use?

Ans: Astronomers measure photon wavelength with spectroscopy; photon intensity with light meters; photon direction by recording two angles; and the variation of wavelength, intensity, and position over time.Link To: The Nature of StarsDifficulty Level: Hard

52. Explain how the Northern Lights are formed.

Ans: The Northern Lights, also called the Aurora Borealis, are flashing colored lights seen in the Earth’s night sky at high northern latitudes when the ions forming the solar wind interact with the Earth's magnetic field in the outer reaches of the Earth’s atmosphere. Link To: The Nature of StarsDifficulty Level: Hard

53. How can the ashes of one stellar nuclear fire become the fuel for the next stellar nuclear fire?

Ans: In medium size stars, hydrogen is burned in nuclear fusion reactions to form helium and, in the later stages, the helium ash is burned to produce carbon. The carbon itself cannot ignite in stars the size of our Sun. In very large stars, the pressure in the cores is sointense that the carbon can be changed by fusion into even larger nuclei like oxygen and silicon.Link To: The Life Cycles of StarsDifficulty Level: Hard

255

Page 14: SAS Astronomi

Chapter 15

54. Why do larger stars have shorter life spans?

Ans: Larger stars may have more hydrogen fuel to burn but have shorter life spans, when compared with small or average size stars. The reason is that large stars must burnhydrogen at rates many times greater than that of smaller stars to overcome the intense force of gravity caused by the star’s massiveness.Link To: The Life Cycles of StarsDifficulty Level: Hard

55. How are naturally occurring elements heavier than iron formed in stellar processes?

Ans: Elements heavier than iron are created when a very large star explodes in a supernova, sending out shockwaves. This raises the temperature and causes collisions of nuclei, which forms new elements.Link To: The Anatomy of StarsDifficulty Level: Hard

56. How are Cepheid variables used to classify stars?

Ans: The distance a star is from the Earth can be determined with triangulation (for nearby stars) or with Cepheid variables. The Cepheid variable stars are standards of comparison for stars greater than a few hundred light-years away using known values of energy output from the star and energy received by Earth. Distance is calculated from comparable brightness (magnitude).Link To: The Variety of StarsDifficulty Level: Hard

57. What advantages might there be to living inside a Dyson Sphere? What would be the limitations future scientists must face before constructing a Dyson Sphere?

Ans: A Dyson sphere would not only intercept and utilize all of a star’s energy, it also could support a tremendous population. Such an immense structure would have an internal surface area comparable to more than 500 million Earth-like planets, and it would be uniformly heated in eternal daylight.Link To: The Anatomy of StarsDifficulty Level: Hard

256

Page 15: SAS Astronomi

Chapter 15

58. How are the original telescopes different from modern telescopes? How do the former improve upon the latter?

Ans: Answers will vary but could include facts about early telescopes using only light whereas modern, non-optical telescopes use other sources of energy to ‘see’ distant objects. Modern non-optical telescopes can be used 24 hours a day, in good weather or bad. Modern optical telescopes have technological advances such as better glass grinding, computer operations, etc.Link To: The Nature of StarsDifficulty Level: Hard

59. When pulsars were first detected, they were called LGM, which stood for Little Green Men. What characteristic of pulsars might have caused astronomers to give them this name?

Ans: Answers will vary but should include reference to the regular pulse rate that appeared as if someone controlled the projection of energy.Link To: The Life Cycles of StarsDifficulty Level: Hard

60. If the Sun had not burned fairly evenly since the creation of the Earth, how would life on Earth be different?

Ans: Answers will vary but could include plant and animal adaptations, different abundances of elements, and so forth.Link To: The Nature of StarsDifficulty Level: Hard

61. If a new star were discovered, what characteristics would it have to have in order to be identified as a main sequence star?

Ans: Medium size, temperature, color.Link To: The Life Cycles of StarsDifficulty Level: Hard

62. During ocean voyages, early sailors used a method called triangulation to determine the location of their ships. How is this same method used today by astronomers to determine the distance to certain neighboring stars?

257

Page 16: SAS Astronomi

Chapter 15

Ans: By measuring the angle of sight to a given star from two points of known separation, we can determine the star’s distance from us.Link To: The Anatomy of StarsDifficulty Level: Hard

63. Evaluate the positive and negative aspects of using a star as an energy source as proposed by the construction of a Dyson Sphere.

Ans: Positive: a source of energy lasting billions of yearsNegative: what to do with the solar wind particles and what happens if the star changes energy output—even by 1-2%?Link To: The Anatomy of Stars Difficulty Level: Hard

64. We don’t often see stars in the daytime, but if you dug a hole deep enough could you see the stars from the bottom?

Ans: Yes, but it would be a hole tens of miles deep.Link To: The Anatomy of StarsDifficulty Level: Hard

65. If some one says to you, “all stars are the same—just tiny points of light”, how might you convince them they have different temperatures (color) and different magnitudes (brightness).

Ans: Answers will vary, however, the human eye is not good at discriminating color at low light levels, but a color photograph can illustrate different colors. As for brightness, light bulbs of the same wattage placed at different distances (or varying wattages placed at the same distances) can illustrate magnitude.Link To: The Variety of StarsDifficulty Level: Hard

66. In the 1800s scientists knew that if the Sun was composed of conventional fuels (coal, oil, wood) it would have a burning life of only a few thousand years at best. How might this information impact the debate of “how old is the Earth” in that era?

Ans: Either the Earth is only a few thousand years old or the Sun is using a different source of fuel—one with a greater lifetime.Link To: The Nature of Stars

258

Page 17: SAS Astronomi

Chapter 15

Difficulty Level: Hard

67. If the Earth had evolved around a different star—a redder star that produced more frequencies in the infrared and microwave bands—how might plant and animal development been altered to respond to these frequencies?

Ans: Answers will vary but for sure if eyes developed they would have to be much larger to receive these longer frequencies. Plants would have evolved chlorophyll that responded to different wavelengths than that of green light.Link To: The Anatomy of StarsDifficulty Level: Hard

68. What elements on the periodic table are the products of supernovae? Why would this be true?

Ans: All elements heavier than iron are formed as a result of higher temperatures and pressures generated by larger stars when they undergo a catastrophic gravitational collapse.Link To: The Life Cycles of StarsDifficulty Level: Hard

69. How is it that optical telescopes are placed in orbit but radio telescopes are not?

Ans: The visible spectrum frequencies are distorted and absorbed by the atmosphere but radio waves pass through relatively undisturbed.Link To: The Nature of StarsDifficulty Level: Hard

259

Page 18: SAS Astronomi

Chapter 15

Chapter 15Cosmology:

Will the universe end?1. Who first showed that the Milky Way is not the only galaxy in the universe?a. Keplerb. Copernicusc. Newtond. Hubblee. Galileo

Ans: dLink To: GalaxiesDifficulty Level: Easy

2. The big bang theory and the theory of the steady state universe differa. because only the big bang theory states that the universe is expanding.b .because only the steady state theory states that the universe is expanding.c. in that only the steady state theory lacks a specific beginning for the universe.d. in that only the steady state universe incorporates an idea about the missing dark matter.e. only in name.

Ans: cLink To: The Big BangDifficulty Level: Easy

3.When astronomers look out at our universe, they see alla. other planets moving away from us.b. other galaxies moving away from us.c. asteroids moving toward us.d. supernovas moving away from us.e. other galaxies moving toward us.

Ans: bLink To: The Redshift and Hubble’s LawDifficulty Level: Easy

4. Which of the following was not a contribution to cosmology by Edwin Hubble?

260

Page 19: SAS Astronomi

Chapter 15

a. the proof that there are other galaxiesb. the idea that far galaxies are moving faster than those nearc. the discovery of the cosmic red shiftd. the realization that evidence for the big bang can come from studies of abundances of chemical elementse. All of these were contributions made by Hubble.

Ans: dLink To: The Redshift and Hubble’s LawDifficulty Level: Easy

5.Hubble’s law tells us thata. the distance to other galaxies can be measured by calculating the blue shift of the light we receive from them.b. the rate at which a galaxy recedes from the Earth is proportional to the square of the distance from the Earth.c. the rate at which a galaxy advances toward the Earth is proportional to its distance from the Earth.d. the distance to other galaxies can be measured by calculating the red shift of the light we receive from them.e. the rate at which a galaxy moves is the Hubble constant.

Ans: dLink To: The Redshift and Hubble’s LawDifficulty Level: Easy

6.The most recent "freezing" of the universe involved the creation ofa. nuclei.b. atoms.c. elementary particles.d. quarks.e. molecules.

Ans: bLink To: The Evolution of the UniverseDifficulty Level: Easy

7.The redshift surveys of the 1980sa. determined the velocity of superclusters.b. were significant in calculating Hubble's constant.

261

Page 20: SAS Astronomi

Chapter 15

c. measured the distance to thousands of galaxies.d. definitively proved the big bang theory.e. provided a foundation for planetary exploration.

Ans: cLink To: The Big BangDifficulty Level: Easy

8. The discovery of a cosmic microwave backgrounda. supported the idea of a steady state universe.b. showed that the universe has a constant heat source.c. proved that matter in the universe is grouped in superclusters.d. gave support to the big bang theory.e. indicated that supernovas produced all known elements.

Ans: dLink To: The Big BangDifficulty Level: Easy

9.What were the first three elements formed in the big bang?a. hydrogen, lithium, and heliumb. hydrogen, oxygen, and heliumc. helium, oxygen, and carbond. carbon, oxygen, and deuteriume. helium, oxygen, lithium

Ans: aLink To: The Big BangDifficulty Level: Easy

10.According to the current ideas about the origin of the universe, which one of the following forces separated at 10-43 seconds?a. the gravitational forceb. the electromagnetic forcec. the strong forced. the weak forcee. All of these forces froze out at the same time.

Ans: aLink To: The Evolution of the Universe

262

Page 21: SAS Astronomi

Chapter 15

Difficulty Level: Easy

11. Which wavelength of radiation is associated with our expanding universe?a. 7.35 nanometersb.7.35 millimetersc. 7.35 centimetersd.7.35 meterse. 7.35 kilometers

Ans: cLink To: The Evolution of the UniverseDifficulty Level: Easy

12. Which of the following is constructed completely from atoms made during the big bang?a. a leafb. the air you are breathingc. boned. a cinder blocke. None of the above is formed completely from atoms created during the big bang.

Ans: eLink To: The Big BangDifficulty Level: Easy

13. According to the big bang theory, what accompanied the freezing of the universe at 10 -35

second after time zero?a. Antimatter was eliminated.b. All four fundamental forces were unified.c. Stable nuclei formed.d. There was a short period of inflation.e. The strong force separated from the weak force.

Ans: dLink To: The Evolution of the UniverseDifficulty Level: Easy

14. At what point after the big bang did the elementary particles form?a. 10-43 second

263

Page 22: SAS Astronomi

Chapter 15

b.10-35 secondc.10-5 secondd. three minutese. 500,000 years

Ans: cLink To: The Big BangDifficulty Level: Easy

15. What is the basis for evidence supporting the theory of an open expanding universe?a. the laws of gravityb. the universe's massc. the proportion of dark matterd. a newly discovered supernovae. all of the above

Ans: eLink To: The Evolution of the UniverseDifficulty Level: Easy

16. Because of research with high energy particle accelerators, scientists have direct experimental checks for the evolution of the universe back toa. 10-43 second after the big bang.b.10-35 second from time zero.c.10-10 second from the beginning.d. three minutes after the big bang.e. one million years following the origin.

Ans: cLink To: The Evolution of the UniverseDifficulty Level: Easy

17. Which statement about dark matter is accepted by most astronomers?a. Dark matter is missing from the Milky Way.b. Dark matter exerts centrifugal forces on antimatter.c. Dark matter emits leptons.d. Dark matter interacts with ordinary matter through a gravitational force.e. all the above

Ans: d

264

Page 23: SAS Astronomi

Chapter 15

Link To: The Evolution of the UniverseDifficulty Level: Easy

18. What experimental evidence supports the big bang theory?a. universal contractionb. creationismc. cosmic microwave radiationd. abundance of lithium, hydrogen, and heliume. c and d

Ans: eLink To: The Big BangDifficulty Level: Easy

19. Antimatter is fairly rare in the universe becausea. antimatter is dark matter that is very difficult to detect with today’s technology.b. cosmic microwave background radiation absorbs antimatter in space.c. antimatter is a short-lived transient state for quarks.d. laboratory research indicates that matter was more plentiful in the early and annihilated the antimatter.e. each galaxy produces a specific type of matter, according to Hubble’s law.

Ans: dLink To: The Evolution of the UniverseDifficulty Level: Easy

20. The rate at which new stars are formeda. has been constant since the big bang.b. was ten times higher seven billion years ago.c. was ten times slower seven billion years ago.d. cannot be calculated with current technology.e. has varied randomly since the big bang.

Ans: bLink To: GalaxiesDifficulty Level: Easy

21. Which of the following describe a quasar?

265

Page 24: SAS Astronomi

Chapter 15

a. highly energeticb. dark matterc. compressed to the size of the Earthd. part of a superclustere. all of the above

Ans: aLink To: GalaxiesDifficulty Level: Easy

22. Before the first stable nuclei were formed, what was the makeup of the universe?a. hydrogen and heliumb. elementary particlesc. atomsd. moleculese. all of the above

Ans: bLink To: The Big BangDifficulty Level: Easy

23. Evidence for the big bang includes thea. observation that the universe is expanding.b. independent evidence that microwave radiation is coming from all directions in space.c. fact that the average temperature of the universe 2.7 Kelvin.d. abundance of light elements. e. all of the above

Ans: eLink To: The Big BangDifficulty Level: Easy

24. How far away is a galaxy that is moving away from Earth at 100,000 km/s? Assume 50 km/s Mpc for the Hubble constant.a. 2000 Mpcb. more than 6 light yearsc. 8000 Mpcd. more than 4 light yearse. a and b

266

Page 25: SAS Astronomi

Chapter 15

Ans: eLink To: The Redshift and Hubble’s LawDifficulty Level: Easy

25.Most galaxies are spiral galaxies.

Ans: TrueLink To: GalaxiesDifficulty Level: Easy

26. Matter in the universe is concentrated in superclusters on the surfaces of huge empty spaces.

Ans: TrueLink To: The Big BangDifficulty Level: Easy

27. The more distant a galaxy is from Earth, the slower it moves away from Earth.

Ans: FalseLink To: The Redshift and Hubble’s LawDifficulty Level: Easy

28. The universe began as a single point and has been expanding for 16 billion years.

Ans: TrueLink To: The Big BangDifficulty Level: Easy

29. Galaxies move in relation to other galaxies like electrons move within an atom.

Ans: FalseLink To: The Redshift and Hubble’s LawDifficulty Level: Easy30. Hubble’s universal expansion theory was the first theory of the universe to incorporate the idea of expansion.

267

Page 26: SAS Astronomi

Chapter 15

Ans: FalseLink To: The Redshift and Hubble’s LawDifficulty Level: Easy

31. The average temperature of the universe is near absolute zero.

Ans: TrueLink To: The Big BangDifficulty Level: Easy

32. Elements with more than three protons in their nucleus were formed in stars, not during the big bang.

Ans: TrueLink To: The Big BangDifficulty Level: Easy

33. Scientists believe they have located the center of the universe.

Ans: FalseLink To: The Big BangDifficulty Level: Easy

34. Gravity is the only force we know of that is capable of ending the expansion of the universe.

Ans: TrueLink To: The End of the UniverseDifficulty Level: Easy

35. When the first nuclei were formed, the universe was mostly filled with plasma.

Ans: TrueLink To: The Big BangDifficulty Level: Easy

268

Page 27: SAS Astronomi

Chapter 15

36. Scientists have combined the weak and the electromagnetic forces using the technology of high-energy physics.

Ans: TrueLink To: The Evolution of the UniverseDifficulty Level: Easy

37. Scientists now believe that 90% of the matter in the universe is made of dark matter.

Ans: TrueLink To: The Evolution of the UniverseDifficulty Level: Easy

38. A closed universe will slow down but never quite stop expanding.

Ans: FalseLink To: The End of the UniverseDifficulty Level: Easy

39. Inflationary theories all agree that since its origin the universe has expanded at a uniform rate.

Ans: FalseLink To: The Evolution of the UniverseDifficulty Level: Easy

40. Why do scientists believe that dark matter does not interact through the electromagnetic force?a. because, if it did, it would absorb or emit photonsb. because it exists too far out into spacec. it exerts no gravitational pull on other matterd. there is too little of it to exert an electromagnetic forcee. all of the above

Ans: aLink To: The Evolution of the UniverseDifficulty Level: Medium

269

Page 28: SAS Astronomi

Chapter 15

41. In what way is the Milky Way a typical galaxy?

Ans: Spiral, has black hole at center.Link To: GalaxiesDifficulty Level: Medium

42. How do we know the Milky Way is a spiral galaxy?

Ans: This has been determined through the study of Doppler shifts and Cepheid variable stars.Link To: GalaxiesDifficulty Level: Medium

43. In the night sky the Milky Way appears as a band of stars across the night sky. How does this fit with the model of a spiral galaxy?

Ans: In a spiral galaxy the stars should be flattened into a disk and should appear as a strip of stars as viewed on end.Link To: GalaxiesDifficulty Level: Medium

44. Astronomers estimate there is something on the order of 100 billion galaxies in the observable universe. How are such numbers generated? How long would it take to count to 100 billion at the rate of one number per second? Does this suggest that anyone has actually counted the galaxies?

Ans: Numbers are generated statistically; it would take over 3000 years to count the galaxies.Link To: GalaxiesDifficulty Level: Medium

45. Make a case for the ultimate fate of the universe: a closed, an open, or a flat universe.

Ans: Answers will vary, but in essence, it depends on the rate of expansion, and the amount of mass and/or dark matter/energy in the universe.Link To: The End of the UniverseDifficulty Level: Medium

270

Page 29: SAS Astronomi

Chapter 15

46. A popular rock song of the 1960s proclaimed, “We are stardust . . . billion year old carbon…” Was the band correct about this? Why or why not?

Ans: Yes, all the chemical elements on the periodic table come from the big bang and the life cycle of stars.Link To: The Big BangDifficulty Level: Medium

47. In what way are dark matter and dark energy related?

Ans: Answers will vary, however dark matter appears to be a gravitational tug on galaxies; dark energy appears to account for the acceleration of the universe.Link To: The Evolution of the UniverseDifficulty Level: Medium

48. What would happen to the age of the universe if Hubble’s constant changes with future observations?

Ans: If it increases, the universe will be older; if it decreases, the universe will be younger than current calculations.Link To: The Redshift and Hubble’s LawDifficulty Level: Medium

49. Why was the existence of other galaxies in the universe demonstrated when Hubble measured the distance to the Andromeda nebula?

Ans: The Andromeda nebula was so far away (2 million light-years) that Hubble knew it must be outside the Milky Way galaxy, which is only 100,000 light-years across.Link To: The Redshift and Hubble’s LawDifficulty Level: Hard

50. How did scientists calculate the value of Hubble’s constant?

Ans: Scientists, including Hubble, plotted the velocity of the recession of many galaxies (using redshift data) against their respective distances from Earth (measured by Cepheidvariables). The slope of the straight line coming closest to all the data points is the best estimate of Hubble’s constant.

271

Page 30: SAS Astronomi

Chapter 15

Link To: The Redshift and Hubble’s LawDifficulty Level: Hard

51. What are scientists trying to discover when they make “red shift surveys” of the sky?

Ans: Astronomers making these surveys are looking at distant galaxies and determining the distance these galaxies are from the Earth by the rate at which these galaxies are moving away from us on Earth. The phenomenon is similar to the Doppler effect forsound waves.Link To: The Redshift and Hubble’s LawDifficulty Level: Hard

52. Place the celestial objects in order by size from planet being the smallest to supercluster being the largest. How do astronomers know ‘for sure’ our position in the universe?

Ans: Answers will vary but must include: Earth, the Sun, a star that can become a supernova, the Milky Way, Local Group, a supercluster. We know our position through observations and calculations of our relative position other celestial objects. Link To: GalaxiesDifficulty Level: Hard

53. Explain the phrase "ripples at the beginning of time" associated with dark matter theories.

Ans: The effect of an unseen gravitational force on hydrogen in space is theorized to be "dark matter." If this dark matter were organized in clumps at the beginning of the universe, luminous matter would be separated to create the structure of the universe we see today. Link To: The Big BangDifficulty Level: Hard

54. Why are changes of state in the early universe referred to as “freezings?"

Ans: Freezings refer to dramatic changes in the fabric of the universe as it expanded and cooled. Each freezing was a crucial transition, first of forces, then of particles.Link To: The Evolution of the UniverseDifficulty Level: Hard

272

Page 31: SAS Astronomi

Chapter 15

55. What is the significance of the K0L particle discovered by physicists?

Ans: K0L is a particle that decays more often into matter than antimatter. As a consequence, the

matter-antimatter annihilation left residual matter in the universe after the big bang. This explains why there is so little antimatter in the universe.Link To: The Evolution of the UniverseDifficulty Level: Hard

56. How might scientists tell if the universe started to contract?

Ans: One way would be that scientists would observe light emitted from nearby galaxies shifted toward the short wavelengths (for example “blue shifted”) in the electromagnetic spectrum, compared to Earth.Link To: The Redshift and Hubble’s LawDifficulty Level: Hard

57. What significance do scientists attach to the fact that some regions of the sky emit microwave background radiation at slightly higher temperatures than other regions?

Ans: Higher temperatures could only be emitted from regions in space that are more dense than the adjacent regions. Thus these areas appear to mark areas where atoms are first being collected into luminous matter. The data suggest that dark matter pulled visible matter into clumps soon after atoms started to form.Link To: The Big BangDifficulty Level: Hard

58. Compare the future for the three theories of the universe: flat, open, and closed.

Ans: An open universe will expand forever because it does not have enough matter to reduce the speed or reverse the direction of the expanding universe. A closed universe has sufficient matter to reverse the expansion and will eventually fall back on itself. A flat universe will simply halt its expansion after an infinite time.Link To: The Big BangDifficulty Level: Hard

59. What new evidence has led to wider acceptance of the open universe theory?

273

Page 32: SAS Astronomi

Chapter 15

Ans: Astronomers recently reported that using a new standard candle (Type 1a supernova) they were able to measure distances to galaxies at the outer limits of the universe. Comparing light from these galaxies over billions of years, the astronomers believe that the universe is continuing to expand, which is consistent with the open universe theory.Link To: The Big BangDifficulty Level: Hard

60. Review the ideas about the universe embraced by the Greeks, the medieval scholars, Newton, and Hubble. How are these ideas still changing?

Ans: Answers will vary but should include the idea of an earth centered universe, then sun-centered universe with Newton’s laws acting the same no matter where they were located to Einstein’s theories of energy/matter/time, to Hubble’s discovery of other galaxies.Link To: The Redshift and Hubble’s LawDifficulty Level: Hard

61. Compare the expanding-balloon analogy of the universe with the raisin-bread dough analogy. What are their common points? At what point does each analogy fall apart?

Ans: Common points are the parts moving away from a central event. The raisin-bread analogy falls apart in that there isn’t enough dough between raisons to continue the movement at increasing speeds. The balloon analogy fails because it is increasing in only two dimensions.Link To: The Big BangDifficulty Level: Hard

62. List and discuss at least two of the topics that are at the forefront of astronomy research.

Ans: Answers will vary but may include arguments about the definition of planets, the end of the universe, detecting dark matter, and so forth.Link To: The Evolution of the UniverseDifficulty Level: Hard

63. How does the discovery of cosmic microwave background radiation support the big bang theory?

Ans: Suggests a change in temperature, which supports inflation theory.Link To: The Big BangDifficulty Level: Hard

274

Page 33: SAS Astronomi

Chapter 15

64. What type of evidence would you need to support the big bang theory in a public forum with the creationists on the Kansas School Board?Ans: Answers will vary. Faith does not require evidence; theories do.Link To: The Big BangDifficulty Level: Hard

65. Summarize the cosmology principles surrounding the "galaxy problem" in current astronomy.

Ans: Answers will vary but should include information about dark matter and clumping as well as clumping in relation to background radiation.Link To: The Evolution of the UniverseDifficulty Level: Hard

66. How is it that every point in the universe appears to by the center of the universe?

Ans: It is relative because no matter what your observation point, all other galaxies appear to be rushing away from you. Link To: The Redshift and Hubble’s LawDifficulty Level: Hard

67. Traditionally, the fate of the universe is tied to the amount of mass, but what role might dark energy/dark mass play in this fate?

Ans: Answers will vary—among Nobel laureates, as well. As future observations tell us more about dark energy/matter, these observations will allow further theoretical models.Link To: The End of the UniverseDifficulty Level: Hard

68. Why are not all galaxies the same shape and size? What does this suggest about their history?

Ans: Size is a factor of the early gravitational interactions. Shape is a factor of gravitational interaction with other galaxies.Link To: GalaxiesDifficulty Level: Hard

275

Page 34: SAS Astronomi

Chapter 15

69. Predict what you should observe 50 billion years from now if you were to look our on a steady state universe as opposed to a big bang universe.

Ans: In a steady state universe, you would observe the same number and density of galaxies as you see not, but they would be new ones from the ones we observe ‘now’. In an expanding universe if you should see any galaxies at all, they would be few and dim.Link To: The Big BangDifficulty Level: Hard

70. In biology, the structure of an organism suggests its function and its function suggests its history. Can this same analogy be applied to the grouping of super clusters of galaxies in the universe—what does this geometry suggest?

Ans: Answers will vary and no one really knows, but answers must account for clustering and voids.Link To: The Evolution of the UniverseDifficulty Level: Hard

276

Page 35: SAS Astronomi

Chapter 15

Chapter 16Earth and Other Planets:

Is Earth the only planet with life?1. According to the nebular hypothesis, the solar system began asa. a rapidly rotating sun.b. a cloud of dust and gas.c. a cloud containing approximately equal amounts of all naturally occurring elements.d. two comets that collided with a tremendous impact.e. The nebular hypothesis addresses only the formation of stars, not planets.

Ans: bLink To: The Nebular HypothesisDifficulty Level: Easy

2. Which scientist is credited with the discovery of Pluto?a. Percival Lowellb. Isaac Newtonc. Clyde Tombaughd. Galileo Galileie. Pierre Laplace

Ans: cLink To: The Nebular HypothesisDifficulty Level: Easy

3. If only Newton's laws of motion were applied to the solar system,a. Venus's orbit could be the reverse of Earth's orbit.b. Earth's moon could rise in the west and set in the east.c. Mar's orbit could be perpendicular to Jupiter's orbit.d. Saturn's rings could at random angles to their current plane.e. all of the above

Ans: eLink To: The Formation of the Solar SystemDifficulty Level: Easy

277

Page 36: SAS Astronomi

Chapter 15

4. What two elements comprise most of a nebula?a. hydrogen and heliumb. hydrogen and nitrogenc. oxygen and lithiumd. carbon and hydrogene. helium and lithium

Ans: aLink To: The Nebular HypothesisDifficulty Level: Easy

5. Why are the Jovian planets formed from materials different from the terrestrial planets?

a. Terrestrial planets were protected by the asteroid belt between Mars and Jupiter.b. The composition of elements in a planet was a random process after the big bang.c. When the solar system first formed, the heaviest elements sank toward the center of the nebulae and the lightest elements floated out.d. Gaseous Jovian planets, formed farther away from the heat of the Sun, are formed from light weight nebulae "dust."e. Only the terrestrial planets formed from planetesimals.

Ans: dLink To: The Formation of the Solar SystemDifficulty Level: Easy

6. The birth of a solar system would look likea. a huge explosion of rocks and fire.b. a meteor shower.c. thick dust clouds circling a new star.d. a thickening Jovian plane.e. nothing we could ever see or imagine.

Ans: cLink To: The Nebular HypothesisDifficulty Level: Easy

7. The Earth’s layered composition is a consequence ofa. the great bombardment.b. differentiation of materials.c. isolation.d. condensation currents.

278

Page 37: SAS Astronomi

Chapter 15

e. plate tectonics.

Ans: bLink To: The Nebular HypothesisDifficulty Level: Easy

8. The inner core at the center of the Eartha. contains the heaviest elements of the Earth’s mass.b. is made from rocks similar to those on the Earth's surface.c. contains a mixture of solids, liquids, and gases.d. is under low pressure, but at a very high temperature.e. all of the above

Ans: aLink To: The Nebular HypothesisDifficulty Level: Easy

9. The mantle of the Earth can be described asa. the metallic core.b. containing hot, melted rock.c. the surface of the Earth.d. primarily gaseous.e. helium, oxygen, magnesium, silicon.

Ans: bLink To: The Nebular HypothesisDifficulty Level: Easy

10. In our solar system, we can say that moonsa. were most likely formed by spinning planets throwing off big chunks of material.b. are all about the same size.c. have less gravitational pull than that found on any planet.d. usually have active volcanoes.e. have been found orbiting all planets except for Mercury and Venus.

Ans: eLink To: The Formation of the Solar SystemDifficulty Level: Easy

11. The composition of the Earth’s Moon is most like

279

Page 38: SAS Astronomi

Chapter 15

a. Mars.b. the Earth’s crustal material.c. an asteroid.d. the Earth’s mantle.e. a comet.

Ans: dLink To: The Formation of the Solar SystemDifficulty Level: Easy

12.Scientists study meteoritesa. because they contain the material from which the solar system was made.b. to find out more about how and when the Earth was created.c. to find out more about other parts of the solar system.d. for all the above reasons.e. Scientists cannot study meteorites because they burn up when they hit the Earth's atmosphere.

Ans: dLink To: The Outer Solar SystemDifficulty Level: Easy

13. After the Earth was formeda. it was bombarded by huge chunks of rock.b. outgassing ended.c. its atmosphere remained virtually unchanged.d. the densest materials collected as the Earth's crust.e. its temperature was too cold to support life.

Ans: aLink To: The Outer Solar SystemDifficulty Level: Easy

14. A comparison of asteroids and terrestrial planets would reveal that both area. made primarily of gases.b. relatively rocky and small.c. composed of chunks of ice surrounded by solid material.d. located beyond the effect of solar heat and wind.e. large and dense, compared to the Jovian planets.

Ans: b

280

Page 39: SAS Astronomi

Chapter 15

Link To: The Outer Solar SystemDifficulty Level: Easy

15. The “big splash” theory of the Moon’s formationa. was disproven during the Apollo lunar mission.b. states that the Moon was formed elsewhere in the Solar System and was captured by Earth’s gravitational force.c. suggests that the Moon was thrown from a spinning Earth.d. states that the Earth was struck by a huge object, causing a large amount of mantle material to be blown into orbit.e. suggests that the Moon was formed by light, less dense materials that floated into the orbit around the Earth.

Ans: dLink To: The Nebular HypothesisDifficulty Level: Easy

16. The early atmosphere on Earth includeda. methane (CH4).b. water vapor (H2O).c. ammonia (NH3).d. carbon dioxide (CO2).e. all of the above

Ans: eLink To: The Nebular HypothesisDifficulty Level: Easy

17. What are some health hazards of long space trips?a. Astronauts can develop skin cancer from direct UV-rays.b. Unidentified microbes create a possible danger of infection.c. Weight gain is common because of the high calorie foods. d. Bone mass is lost increasing the chance of breaks.e. All of the above can happen.

Ans: dLink To: The Nebular HypothesisDifficulty Level: Easy18. An astronaut standing on Mars and attempting to look at Jupiter might have her view partly blocked by the intervening

281

Page 40: SAS Astronomi

Chapter 15

a. Oort Cloud.b. rings of Saturn.c. asteroid belt.d. moon Triton.e. Sun.

Ans: cLink To: The Formation of the Solar SystemDifficulty Level: Easy

19. The Earth’s atmosphere has probably been affected by all of the following except fora. volcanoes.b. strong solar winds.c. Amazon jungles.d. the number of living things on Earth.e. increased amounts of hydrogen and helium.

Ans: eLink To: The Nebular HypothesisDifficulty Level: Easy

20. The process that formed the structure of the Earth and other terrestrial planets isa. convection.b. gravity.c. differentiationd. acceleration.e. tectonics.

Ans: cLink To: The Nebular HypothesisDifficulty Level: Easy

21. Transfer of material from space to Eartha. stopped after the great bombardment.b. started after the great bombardment.c. has been measured at 20 metric tons daily.d. will double the mass of the Earth in 4 billion years.e. continues at an estimated rate of 20 metric tons annually.

Ans: c

282

Page 41: SAS Astronomi

Chapter 15

Link To: The Nebular HypothesisDifficulty Level: Easy

22. What new astronomical information resulted from the impact of the comet Shoemaker-Levy on Jupiter in 1994?a. effect of hydrogen bombs on Jupiter's atmosphereb. composition of atmosphere beneath the planet's surfacec. the number of volcanoes located within 100 km of the impactd. amount of water in Jupiter's atmospheree. mineral analysis of Jupiter's core

Ans: bLink To: The Outer Solar SystemDifficulty Level: Easy

23. The diamond anvil can attain pressures that exceed pressures at the center of the Earth.

Ans: TrueLink To: The Nebular HypothesisDifficulty Level: Easy

24. The largest moon in our solar system is about the same size as the smallest planet.

Ans: TrueLink To: The Formation of the Solar SystemDifficulty Level: Easy

25.. Pluto's moon Charon was captured during the great bombardment.

Ans: FalseLink To: The Outer Solar SystemDifficulty Level: Easy

26. Comets can originate in two regions outside our solar system.

Ans: True

283

Page 42: SAS Astronomi

Chapter 15

Link To: The Outer Solar SystemDifficulty Level: Easy

27. Extrasolar planets have been discovered by an adaptation of the Doppler effect.

Ans: TrueLink To: The Outer Solar SystemDifficulty Level: Easy

28. The mantle is the one of two layers of the solid Earth with which human beings have had direct contact.

Ans: FalseLink To: The Nebular HypothesisDifficulty Level: Easy

29. More diamonds can now be manufactured in a year than the total amount of diamonds mined in recorded history.

Ans: TrueLink To: The Nebular HypothesisDifficulty Level: Easy

30. NASA scientists are collaborating with the Center for Disease Control on a mission to collect and bring back surface samples from Mars.

Ans: TrueLink To: Exploring the Solar SystemDifficulty Level: Easy

31. "Hot Jupiters" are large gaseous planets located close to their respective suns in other solar systems.

Ans: TrueLink To: The Outer Solar SystemDifficulty Level: Easy

284

Page 43: SAS Astronomi

Chapter 15

32. The nebulae hypothesis states that only 10% of the original mass became concentrated as the Sun.

Ans: FalseLink To: The Nebular HypothesisDifficulty Level: Easy

33. A comet is a piece of space debris burning up in the Earth’s atmosphere.

Ans: FalseLink To: The Outer Solar SystemDifficulty Level: Easy

34. Pluto’s orbital path sometimes crosses Neptune’s orbital path.

Ans: TrueLink To: The Outer Solar SystemDifficulty Level: Easy

35. What was accomplished by Voyager 1 and Voyager 2?a. remote sensing of the atmosphere of Venusb. collected samples from the asteroid beltc. paved the way for the Moon landingsd. clocked winds on Mercurye. assessment of the outer Solar System environment

Ans: eLink To: The Outer Solar SystemDifficulty Level: Medium

36. How can meteor showers be predicted?a. Meteors follow the jet stream in the upper atmosphere.b. Meteors are in known orbits around the sun after comets.c. Meteors rise in the east and set in the west.

285

Page 44: SAS Astronomi

Chapter 15

d. Telescopes on satellites detect meteors months in advance of their entry into the Earth's atmosphere.e. Calculations made by the Divine Calculator have been used to produce meteor shower schedules.

Ans: bLink To: The Outer Solar SystemDifficulty Level: Medium

37. Which of the following characteristics does the Earth share with all other bodies in the solar system?a. formed from matter ejected by the Sunb. move in circular orbitsc. similar chemical compositiond. equally densee. gravitationally bound to the Sun

Ans: eLink To: The Formation of the Solar SystemDifficulty Level: Medium

38. The density of our Moon is less than the average density of Earth.

Ans: TrueLink To: The Formation of the Solar SystemDifficulty Level: Medium

39. The density of the material on the Moon is less than the density of the Earth.

Ans: TrueLink To: The Formation of the Solar SystemDifficulty Level: Medium

40. The weight of an object on Jupiter's surface is less than it would be on Earth.

Ans: FalseLink To: The Formation of the Solar SystemDifficulty Level: Medium

286

Page 45: SAS Astronomi

Chapter 15

41. How are asteroids different from comets?

Ans: Asteroids are small rocky bodies that are similar in composition to the terrestrial planets and move in orbits around the Sun, primarily in the asteroid belt. Comets have the consistency of a “dirty snowball” of water and methane ice imbedded with some rock. Most comets are located outside the orbit of Pluto in the Oort Cloud or the Kuiper Belt.Link To: The Outer Solar SystemDifficulty Level: Medium

42. Describe the Galileo mission to Jupiter.

Ans: Galileo began study of Jupiter after 1989 launch and six years in space. From an orbit around Jupiter, Galileo probed the atmosphere with a projectile. Galileo continues to orbit Jupiter and send back data about the planet and its moons.Link To: The Outer Solar SystemDifficulty Level: Medium

43. What is the current hypothesis that explains why planets differ in their axis of rotation and direction of spin?

Ans: Early bombardment.Link To: The Nebular HypothesisDifficulty Level: Medium

44. How was the layered structure of the Earth first differentiated?

Ans: Lighter elements rise to the surface; heavy elements sink.Link To: The Nebular HypothesisDifficulty Level: Medium

45. From the density calculation of the Moon (page 328) why would you anticipate that a directional compass would not work on the Moon?

287

Page 46: SAS Astronomi

Chapter 15

Ans: It suggests that the Moon is basically devoid of metals so one would not expect a large amount of metals in the core to produce a magnetic field—indeed, the Moon’s magnetic field is virtually nonexistent.Link To: The Nebular HypothesisDifficulty Level: Medium

46. Explain how the early Earth’s atmosphere must have been very different from the atmosphere we are breathing now?

Ans: The atmosphere had to change from a carbon dioxide dominated one with a trace of oxygen to a nitrogen-oxygen dominated one with a trace of carbon dioxide. This reversal is the product of plants and oceans absorbing carbon dioxide and photosynthesis releasing oxygen into the atmosphere, decaying plants releasing nitrogen.Link To: The Nebular HypothesisDifficulty Level: Medium

47. Discuss the apparent conflict between the nebulae hypothesis and the rotations of planets.

Ans: Planets revolve around the Sun in the same plane and in the same direction, according to the nebulae hypothesis; however, each planet rotates around its own axis at differing angles and directions. Scientists now believe that a planet’s rotation was affected by random collisions with very large objects at some point in its history.Link To: The Nebular HypothesisDifficulty Level: Hard

48. Why do scientists believe there may have been life on Mars?

Ans: Evidence of water locked beneath the surface of Mars comes from several space missions, including Pathfinder (1990s) and Odyssey (2002). A Martian atmosphere was also possible in the past. These are the two prerequisites for formation of life.Link To: Exploring the Solar SystemDifficulty Level: Hard

49. Compare several of the moons of our solar system and what a study of these has taught us about Earth's processes.

Ans: The craters on Earth's moon show evidence of a great bombardment in the past. Jupiter's moon Io has active volcanoes; Europa, has a frozen ocean; Saturn’s moon, Titan, may have

288

Page 47: SAS Astronomi

Chapter 15

organic materials. Each of these moons provides an example of processes that may be similar to those processes forming life on prehistoric Earth.Link To: The Nebular HypothesisDifficulty Level: Hard

50. Draw a simple diagram to show how it is possible for an asteroid to collide with Earth, even though both are in orbit around the Sun.

Ans: Answers will vary, but the diagram should reflect that, at some point, the asteroid’s orbit crosses that of the Earth.Link To: The Outer Solar SystemDifficulty Level: Hard

51. Explain the processes in the evolution of the Earth’s atmosphere beginning with Earth as an airless, molten ball.

Ans: Answers will vary but should include: Volcanoes belched water vapor and carbon dioxide. Atmospheric temperatures dropped. Torrential rains filled ocean basins. Light atmospheric elements escaped to space. Photosynthetic organisms evolved. Free oxygen increases to about 20% of the atmosphere.

Link To: The Nebular HypothesisDifficulty Level: Hard

52. Do you think that space exploration should be carried out with manned or unmanned spacecraft? Explain your answer.

Ans: Answers will vary. Unmanned space craft are safer for humans, however humans can make on-the-spot judgments.Link To: Exploring the Solar SystemDifficulty Level: Hard

53. Describe how the scientific process led to the discovery of Pluto.

Ans: Development of the telescope and pictures of a shifting point of light; observations and interpretations of these observations.Link To: The Outer Solar System

289

Page 48: SAS Astronomi

Chapter 15

Difficulty Level: Hard54. Compare what you would experience during explorations of Jupiter and Venus.

Ans: Answers will vary but should include ideas about changes in weight, in the visibility due to atmospheric variations, plus differences in atmospheric pressure.Link To: Exploring the Solar SystemDifficulty Level: Hard

55. In 1994 the Shoemaker-Levy Comet collided with Jupiter. The impact was predicted, observed, and recorded by astronomers on Earth. What information did the scientists use to predict the time and location of the comet impact?

Ans: Velocity, time and gravitational relationships between the planet and the comet plus the orbits of the comet and Jupiter..Link To: The Outer Solar SystemDifficulty Level: Hard

56. What is the long-range impact of space debris and rock falling to Earth each day? What is the impact of this same material in outer space to the space program?

Ans: Answers will vary but should include information about foreign biological materials which could be found within meteorites, small impact craters to wide-scale destruction, as well as the ability to study materials from space. Answers should also include danger to astronauts, ability to study materials while still in orbit and so forth.Link To: The Outer Solar SystemDifficulty Level: Hard

57. The “Death Star” hypothesis has been used to explain the extinction of the dinosaurs during the Cretaceous period. How could this impact kill animals on all parts of the Earth? What are the chances of this happening again?

Answers will vary; one theory is that it decreased the temperature of the atmosphere thereby killing all animals/plants that could not adapt to the relatively immediate change. Chances range from very high to very low depending on the data reported.Link To: The Outer Solar SystemDifficulty Level: Hard

290

Page 49: SAS Astronomi

Chapter 15

58. Describe two fictional life forms that have internal skeletons: one adapted to life on Pluto and one adapted to life on Saturn. Why would they be different?

Ans: Answers will vary but should include adaptation to different gravitation and to different temperatures and light.Link To: The Nebular HypothesisDifficulty Level: Hard

59. How important are volcanoes to the creation of an atmosphere? Use several examples from our solar system in your answer.

Ans: Outgassing released new atmosphere. Volcanoes on Earth, Mars, Jupiter’s moons, all of which have or had atmospheres as can be shown by the surface of the planet.Link To: The Nebular HypothesisDifficulty Level: Hard

60. If the Nebular hypothesis is correct, then what physical and chemical aspects of the solar system does it account for? Are there any outlier phenomena?

Ans: It accounts for the mechanical motions, rotation and revolution of the Sun and all planets and respective moons. Aberrant motions can be accounted for by subsequent impacts and, in the case of moons, captured by larger bodies. Chemically it accounts for the chemical and density segregation of the planets.Link To: The Nebular HypothesisDifficulty Level: Hard

61. Explain the relationship between meteor showers and comets.

Ans: Meteor showers are the result of the earth running into the dusty orbits of previous comet’s journey around the Sun.Link To: The Outer Solar SystemDifficulty Level: Hard

62. Explain how the ‘seasons’ would be represented on Uranus.

291

Page 50: SAS Astronomi

Chapter 15

Ans: With the northern hemisphere always pointed toward the Sun, only the northern hemisphere would receive any daylight, therefore any ‘seasonal’ change would be the result of changing one’s latitude.Link To: The Nebular HypothesisDifficulty Level: Hard63. Even through Saturn’s size is about eight Earth diameters, your weight (earth standard) would be about the same if you stand on Saturn’s ‘surface’. What does this suggest about the composition of the ringed planet?

Ans: Although bigger in volume, Saturn must be much less dense than Earth, so one’s body weight on Earth should be very similar on Saturn (100 pounds on earth ≈ 106 pounds on Saturn).Link To: The Formation of the Solar SystemDifficulty Level: Hard

64. Both the Earth and moon have craters but the smaller moon has millions more than the Earth. If they both formed at the same time and under similar conditions, how can you account for this discrepancy?

Ans: The Earth being the larger target probably had several times the impacts of the moon, but the process of weathering and plate tectonics have erased much of the Earth’s surface features.Link To: The Nebular HypothesisDifficulty Level: Hard

65. What physical and chemical characteristics does the ‘big splash’ hypothesis (earth-moon formation) account for?

Ans: It accounts for the motions of the earth and moon operating as a mechanical system: further it accounts for the density difference between the two bodies (Earth being more dense) and the lack of gases and metals in moon rocks.Link To: The Nebular HypothesisDifficulty Level: Hard

292