1. a) the Earth orbits the Sun. b) the Moon orbits the Earth. c) stars are in constant motion. d) the Sun orbits the Earth. e) the Earth spins on its axis. Question 1 Constellations appear to move across the sky at night because

2. Question 1 1) the motion of Earth around the Sun 2) the motion of the Moon around Earth 3) the motion of Mars around the Sun 4) the motion of the constellations around Earth 5) the spinning of Earth on its axis What motion is responsible for the apparent motion of the constellations (east to west) across the sky? a) the Earth orbits the Sun. b) the Moon orbits the Earth. c) stars are in constant motion. d) the Sun orbits the Earth. e) the Earth spins on its axis. Question 1 Constellations appear to move across the sky at night because The Sun, Moon, planets, and stars all rise and set because our planet rotates once each day.

3. a) Wobble of Earth’s rotation axis b) the greenhouse effect c) 23.5° tilt of Earth’s rotational axis d) movement of Earth closer to or farther from the Sun e) global warming and cooling What causes Earth’s seasons? Question 2

4. a) Wobble of Earth’s rotation axis b) the greenhouse effect c) 23.5° tilt of Earth’s rotational axis d) movement of Earth closer to or farther from the Sun e) global warming and cooling What causes Earth’s seasons? Question 2 Our planet’s tilt, and not its changing distance from the Sun, creates seasons.

5. Question 3 What is the path that the Sun, Moon, and planets follow through the constellations? a) the celestial equator b) the north celestial pole c) the Milky Way d) the zodiac e) the ecliptic

6. a) the celestial equator b) the north celestial pole c) the Milky Way d) the zodiac e) the ecliptic Question 3 What is the path that the Sun, Moon, and planets follow through the constellations? The ecliptic also marks the plane of Earth’s orbit around the Sun.

7. How long does it take the Sun to complete one circuit of the ecliptic? Question 4 a) one hour b) one day c) one month d) one year e) one decade

8. 1) one hour 2) one day 3) one month 4) one year 5) one decade How long does it take the Sun to complete one circuit of the ecliptic? Question 4 The Sun moves around the ecliptic once as the Earth orbits in one year.

9. a) one day b) one hour c) one week d) one month e) one year Question 5 How long does it take the Moon to go around the ecliptic?

10. a) one day b) one hour c) one week d) one month e) one year Question 5 How long does it take the Moon to go around the ecliptic? The Moon orbits Earth in a month, and passes in front of the constellations of the zodiac, which are arranged around the ecliptic.

11. Stars in a constellation are Question 6 a) physically close to each other. b) usually equal in brightness. c) about the same age. d) about the same distance away. e) in the same part of the sky.

12. Question 6 a) physically close to each other. b) usually equal in brightness. c) about the same age. d) about the same distance away. e) in the same part of the sky. Stars in a constellation are Stars within a constellation might be very different distances, ages, types, and brightnesses.

13. a) during the new moon phase. b) when the Sun blocks the Moon. c) during the full moon phase. d) always around the summer solstice. A total lunar eclipse occurs Question 7

14. a) during the new moon phase. b) when the Sun blocks the Moon. c) during the full moon phase. d) always around the summer solstice. A total lunar eclipse occurs Question 7

15. Question 8 a) summer. b) fall. c) winter. d) spring. The vernal equinox marks the beginning of

16. Question 8 a) summer. b) fall. c) winter. d) spring. The vernal equinox marks the beginning of The vernal equinox occurs around March 21–22.

17. a) every month at new moon. b) every week at the quarter phases. c) every month at full moon. d) about every six months at new moon. e) every year at new moon. A solar eclipse happens Question 9

18. a) every month at new moon. b) every week at the quarter phases. c) every month at full moon. d) about every six months at new moon. e) every year at new moon. Question 9 A solar eclipse happens

19. The angle of parallax increases as Question 10 a)distances to stars increase. b)the baseline gets larger. c) the baseline gets smaller. d) the Earth moves faster in its orbit.

20. a)distances to stars increase. b)the baseline gets larger. c) the baseline gets smaller. d) the Earth moves faster in its orbit. The angle of parallax increases as Question 10 The greater the distance between two observation points (the baseline), the larger the angle of parallax.

21. a)the same phase in 24 hours. b)different phases in 24 hours. c) a lunar eclipse once a month. d) different sides of the Moon. Considering the Moon’s phases, everyone on Earth sees Question 11

22. a)the same phase in 24 hours. b)different phases in 24 hours. c) a lunar eclipse once a month. d) different sides of the Moon. Considering the Moon’s phases, everyone on Earth sees Question 11 The Moon goes through its cycle of phases in about 30 days; the Earth rotates once in only 24 hours. So everyone has a chance to see the same phase!

23. a) planets move on epicycles. b) planets orbit the Sun in the same direction. c) Earth moves faster in its orbit. d) they are closer than Uranus. e) they rotate quickly on their axes. Mars, Jupiter, and Saturn show retrograde motion because Question 1

24. a) planets move on epicycles. b) planets orbit the Sun in the same direction. c) Earth moves faster in its orbit. d) they are closer than Uranus. e) they rotate quickly on their axes. Mars, Jupiter, and Saturn show retrograde motion because Question 1 As Earth overtakes and “passes” the outer planets, they seem to slow down and then reverse direction.

25. a) The Earth rotated. b) The Sun rotated. c) The geocentric model couldn’t account for day and night. d) The Earth revolved around the Sun. e) The Sun orbited Earth. How did the geocentric model account for day and night on Earth? Question 2

26. a) The Earth rotated. b) The Sun rotated. c) The geocentric model couldn’t account for day and night. d) The Earth revolved around the Sun. e) The Sun orbited Earth. How did the geocentric model account for day and night on Earth? Question 2 The geocentric model held that the Earth was motionless in the center of the universe.

27. a) why planets moved in the sky. b) why Earth was at the center. c) why retrograde motion occurred. d) why Earth wobbled on its axis. e) why inner planets were always seen near the Sun. Epicycles were used in Ptolemy’s model to explain Question 3

28. a) why planets moved in the sky. b) why Earth was at the center. c) why retrograde motion occurred. d) why Earth wobbled on its axis. e) why inner planets were always seen near the Sun.. Epicycles were used in Ptolemy’s model to explain Question 3 Planets were assumed to move uniformly on an epicycle, as it moved uniformly around Earth.

29. a) stars don’t seem to show any parallax. b) we don’t feel as though Earth moves. c) objects fall toward Earth, not the Sun. d) we don’t see an enormous wind. e) All of the above were valid reasons. The geocentric model was supported by Aristotle because Question 4

30. a) stars don’t seem to show any parallax. b) we don’t feel as though Earth moves. c) objects fall toward Earth, not the Sun. d) we don’t see an enormous wind. e) All of the above were valid reasons. The geocentric model was supported by Aristotle because Question 4 Aristotle thought that if the Earth rotated and orbited, we would feel its motion. In Aristotle’s time, the size of the solar system and distances to stars were assumed to be much, much smaller. Parallax was expected to be seen.

31. a) planets move on epicycles. b) Earth is the center of the solar system. c) the stars move on the celestial sphere. d) the Sun is the center of the solar system. e) Earth’s axis wobbles over 26,000 years. The heliocentric model assumes Question 5

32. 1) planets move on epicycles. 2) Earth is the center of the solar system. 3) the stars move on the celestial sphere. 4) the Sun is the center of the solar system. 5) Earth’s axis wobbles over 26,000 years. The heliocentric model assumes Question 5 Heliocentric models proposed by Aristarchus and others were considered wrong by Aristotle and his followers.

33. Question 6 Copernicus’ important contribution to astronomy was a) proving planets move around the Sun in elliptical orbits. b) the theory of gravity. c) proposing a simpler model for the motions of planets in the solar system. d) discovering the Sun was not at the center of the Milky Way. e) discovering the four moons of Jupiter.

34. Question 6 Copernicus’ important contribution to astronomy was a) proving planets move around the Sun in elliptical orbits. b) the theory of gravity. c) proposing a simpler model for the motions of planets in the solar system. d) discovering the Sun was not at the center of the Milky Way. e) discovering the four moons of Jupiter. His heliocentric model easily explained retrograde motion because planets orbited the Sun at different speeds.

35. Question 7 Copernicus’ heliocentric model was flawed because a) he assumed planets moved in ellipses. b) he didn’t know about Uranus & Neptune. c) he couldn’t account for gravity. d) he couldn’t explain retrograde motion. e) he assumed planets moved in circles.

36. Question 7 Copernicus’ heliocentric model was flawed because a) he assumed planets moved in ellipses. b) he didn’t know about Uranus & Neptune. c) he couldn’t account for gravity. d) he couldn’t explain retrograde motion. e) he assumed planets moved in circles. Copernicus’ model still needed small epicycles to account for observed changes in planetary speeds.

37. a) Hipparchus b) Galileo c) Tycho d) Copernicus e) Kepler Question 8 Who published the first astronomical observations made with a telescope?

38. a) Hipparchus b) Galileo c) Tycho d) Copernicus e) Kepler Question 8 Who published the first astronomical observations made with a telescope? Galileo published the “Starry Messenger” in 1610, detailing his observations of the Moon, Jupiter’s moons, stars, and nebulae.

39. a) craters on the Moon b) sunspots c) lunar maria d) satellites of Jupiter e) stars of the Milky Way Which of Galileo’s initial observations was most challenging to established geocentric beliefs? Question 9

40. a) craters on the Moon b) sunspots c) lunar maria d) satellites of Jupiter e) stars of the Milky Way Which of Galileo’s initial observations was most challenging to established geocentric beliefs? Question 9 Seeing four moons clearly move around Jupiter disproved that everything orbited Earth and showed Earth could orbit the Sun and not lose its moon, too.

41. Question 10 a) Kepler b) Newton c) Galileo d) Tycho Brahe e) Copernicus Which hero of the Renaissance postulated three “laws” of planetary motion?

42. Question 10 a) Kepler b) Newton c) Galileo d) Tycho Brahe e) Copernicus Which hero of the Renaissance postulated three “laws” of planetary motion? Note that Isaac Newton is also well known for three general laws of motion. But Kepler’s laws are about objects in orbits, like planets orbiting a star.

43. a) planets orbit the Sun. b) orbits are noncircular. c) orbits are elliptical in shape. d) All of the above are stated. Question 11 Kepler’s 1st law of planetary orbits states that

44. a) planets orbit the Sun. b) orbits are noncircular. c) orbits are elliptical in shape. d) All of the above are stated. Question 11 Kepler’s 1st law of planetary orbits states that Kepler’s laws apply to all orbiting objects. The Moon orbits Earth in an ellipse, and the Space Shuttle orbits Earth in an ellipse, too.

45. Question 12 Earth is closer to the Sun in January. From this fact, Kepler’s 2 nd law tells us a) Earth orbits slower in January. b) Earth orbits faster in January. c) Earth’s orbital speed doesn’t change.

46. Earth is closer to the Sun in January. From this fact, Kepler’s 2 nd law tells us a) Earth orbits slower in January. b) Earth orbits faster in January. c) Earth’s orbital speed doesn’t change. Kepler’s 2 nd law means that a planet moves faster when closer to its star. Faster Slower Question 12

47. Question 13 Kepler’s 3 rd law relates a planet’s distance from the Sun and its orbital a) speed. b) period. c) shape. d) velocity.

48. Kepler’s 3 rd law relates a planet’s distance from the Sun and its orbital a) speed. b) period. c) shape. d) velocity. Kepler’s 3 rd law P 2 = a 3 means more distant planets orbit more slowly. Question 13 Venus’ period = 225 days Venus’ axis = 0.7 AU Earth’s period = 365 days Earth’s axis = 1.0 AU

49. Question 14 Newton’s law of gravity states that the force between two objects a) increases with distance. b) depends on the state of matter (solid, liquid, or gas). c) can be attractive or repulsive. d) increases with mass.

50. Question 14 Newton’s law of gravity states that the force between two objects a) increases with distance. b) depends on the state of matter (solid, liquid, or gas). c) can be attractive or repulsive. d) increases with mass. The attractive force of gravity INCREASES with greater mass, and DECREASES QUICKLY with greater distance. The force doesn’t depend on the kind of matter.

51. a) gamma rays b) infrared c) sound d) visible light e) radio Which of these is NOT a form of electromagnetic radiation? Question 1

52. a) gamma rays b) infrared c) sound d) visible light e) radio Which of these is NOT a form of electromagnetic radiation? Question 1 Sound comes from pressure waves; all others are types of EM radiation of different wavelengths.

53. a) wavelength b) frequency c) period d) amplitude e) energy The distance between successive wave crests defines the ________ of a wave. Question 2

54. a) wavelength b) frequency c) period d) amplitude e) energy The distance between successive wave crests defines the ________ of a wave. Question 2 Light can range from short- wavelength gamma rays to long-wavelength radio waves.

55. a) radius. b) mass. c) magnetic field. d) temperature. e) direction of motion. The frequency at which a star’s intensity is greatest depends directly on its Question 3

56. a) radius. b) mass. c) magnetic field. d) temperature. e) direction of motion. The frequency at which a star’s intensity is greatest depends directly on its Question 3 Wien’s Law means that hotter stars produce much more high- frequency light.

57. Question 4 a) cooler than b) the same temperature as c) older than d) hotter than e) more massive than The constellation ORION Rigel appears as a bright bluish star, whereas Betelgeuse appears as a bright reddish star. Rigel is ______ Betelgeuse. Betelgeuse Rigel

58. Question 4 Rigel appears as a bright bluish star, whereas Betelgeuse appears as a bright reddish star. Rigel is ______ Betelgeuse. The constellation ORION Betelgeuse Rigel a) cooler than b) the same temperature as c) older than d) hotter than e) more massive than Hotter stars look bluer in color; cooler stars look redder.

59. a) its spectral lines are redshifted. b) the light is much brighter. c) its spectral lines are shorter in wavelength. d) the amplitude of its waves has increased. e) its photons have increased in speed. If a light source is approaching you, you will observe Question 5

60. a) its spectral lines are redshifted. b) the light is much brighter. c) its spectral lines are shorter in wavelength. d) the amplitude of its waves has increased. e) its photons have increased in speed. If a light source is approaching you, you will observe Question 5 The Doppler Shift explains that wavelengths from sources approaching us are blueshifted.

61. Question 6 The wavelengths of emission lines produced by an element a) depend on its temperature. b) are identical to its absorption lines. c) depend on its density. d) are different than its absorption lines. e) depend on its intensity.

62. Question 6 The wavelengths of emission lines produced by an element a) depend on its temperature. b) are identical to its absorption lines. c) depend on its density. d) are different than its absorption lines. e) depend on its intensity. Elements absorb or emit the same wavelengths of light based on their electron energy levels.

63. Question 7 Analyzing a star’s spectral lines can tell us about all of these EXCEPT a) its composition. b) its surface temperature. c) its transverse (side-to-side) motion. d) its rotation. e) its density.

64. Question 7 Analyzing a star’s spectral lines can tell us about all of these EXCEPT a) its composition. b) its surface temperature. c) its transverse (side-to-side) motion. d) its rotation. e) its density. Only motion toward or away from us influences a star’s spectral lines. Spectra can also tell us about a star’s magnetic field.

65. Question 8 What types of electro- magnetic radiation from space reach the surface of Earth? a) radio & microwaves b) X rays & ultraviolet light c) infrared & gamma rays d) visible light & radio waves e) visible & ultraviolet light

66. Question 8 What types of electro- magnetic radiation from space reach the surface of Earth? a) radio & microwaves b) X rays & ultraviolet light c) infrared & gamma rays d) visible light & radio waves e) visible & ultraviolet light Earth’s atmosphere allows radio waves and visible light to reach the ground.

67. Question 9 Which of the following has a fundamentally different nature than the other four? a) proton b) electron c) neutron d) atomic nucleus e) photon

68. Question 9 Which of the following has a fundamentally different nature than the other four? a) proton b) electron c) neutron d) atomic nucleus e) photon Photons are packages of light energy. Protons, neutrons, & electrons are particles of matter within an atomic nucleus.

69. Clicker Question: Compared to blue light, red light travels: A: faster B: slower C: at the same speed

70. Clicker Question: A star much colder than the sun would appear: A: red B: yellow C: blue D: smaller E: larger

71. Clicker Question: If a star is moving rapidly towards Earth then its spectrum will be: A: the same as if it were at rest B: shifted to the blue C: shifted to the red D: much brighter than if it were at rest E: much fainter than if it were at rest

72. Clicker Question: Compared to ultraviolet radiation, infrared radiation has greater: A: energy B: amplitude C: frequency D: wavelength

73. Clicker Question: The energy of a photon is proportional to its: A: period B: amplitude C: frequency D: wavelength