1. According to Kepler's Second Law, an object in an elliptical orbit around the Sun is travelling fastest when it is at what position?
a) when it is closest to the Sun.
b)when it is farthest from the Sun.
c) when it is in an epicycle.
d) when it is approaching the Sun.
e) it travels at a constant speed.

2. A planet orbiting the Sun with a orbital semi-major axis of 1.5 AU has a sidereal period of:
a) 0.8 years.
b) 1 year.
c) 1.5 years.
d) 1.8 years.
e) 18 years.

3. Nicolaus Copernicus is best known for:
a) His telescopic observations of the Sun, moon, and planets.
b) His accurate observations over many years of the positions of the stars and planets.
c) His detailed calculations of the orbits of the planets around the Sun.
d) His calculation of the diameter of the Earth.
e) His book entitled `On the Revolution of the Celestial Sphere'

4. The orbit of Mars around the Sun is:
a) a circle.
b) an ellipse, with the Sun at the center.
c) an ellipse, with the Sun at one focus and the Earth at the other focus.
d) an ellipse, with the Sun at one focus and the other empty.
e) an ellipse, with the Earth at the center.

5. If you are moving through empty space at 10 km/s, far from any stars or planets, what forces are needed to keep you moving at 10 km/s in the same direction?
a) none.
b) one force, in the direction of motion.
c) one force, in the direction opposite your motion.
d) two unequal forces, in opposite directions.
e) two equal forces, in opposite directions.

6. Apollonius explained the retrograde motion of Mars by:
a) Epicycles.
b) Elliptical orbits.
c) Inertia.
d) Parallax shifts.
e) the Earth catching up and passing Mars in its orbit.

7. Anaxagoras is best known for his explanation of:
a) the phases of the Moon and eclipses.
b) the phases of Venus.
c) sunspots.
d) the size of the Earth.
e) the Dresden Codex.

8. The angular size of Venus is largest when:
a) it is in its crescent phase.
b) it is in its quarter phase.
c) it is in its full phase.
d) the angular size of Venus is not related to its phase.
e) it is observed at midnight.

9. The eccentricity of a perfect circle is:
a) 0
b) 1
c) 0.5
d) 0.25
e) it depends upon the radius of the circle.

10. The moon Io was discovered by:
a) Anaxagoras.
b) Eratosthenes.
c) Hipparcus.
d) Tycho Brahe.
e) Galileo.

11. In ancient Chinese astrology, what was considered especially important?
a) the constellations along the ecliptic.
b) the planet Venus.
c) the location of the Sun and Moon in the sky.
d) astronomical events in the circumpolar region.
e) the 12 signs of the zodiac (Taurus, Leo, etc.)

12. Which of the following is NOT considered evidence that the Earth is a sphere?
a) the constellations change as one changes location on the Earth.
b) the angle between the Sun and zenith changes as one goes north or south.
c) during a lunar eclipse, the Earth's shadow is curved.
d) the angle between the Sun and the Moon during a first quarter moon is almost 90 degrees.
e) when a ship sails away over the ocean, the sail disappears last.

13. Which of the following did we inherit from the ancient Babylonians?
a) The concept of a spherical Earth.
b) The heliocentric Universe model.
c) The modern explanation of the phases of the Moon.
d) The modern explanation of eclipses.
e) The concept of a degree.

14. Aristarchus supported a heliocentric Universe model because:
a) he measured stellar parallax shifts.
b) he observed moons orbiting Jupiter.
c) he observed the phases of Venus.
d) he calculated the relative size of the Sun and Earth.
e) he calculated the size of the Earth.

15. The Earth moves fastest in its orbit, in km/s, when it is:
a) 1.0 A.U. from the Sun.
b) 0.98 A.U. from the Sun.
c) 1.02 A.U. from the Sun.
d) 1.5 A.U. from the Sun.
e) it always moves at exactly the same speed.

16. If a comet orbiting the Sun has a sidereal period of 8 years, what would be the semi-major axis of its orbit?
a) 1 A.U.
b) 2 A.U.
c) 4 A.U.
d) 8 A.U.
e) 64 A.U.

17. One of the original uses of the Big Horn Medicine Wheel may have been:
a) to measure the size of the Earth.
b) to measure the relative size of the Earth and the Moon.
c) as an astronomical observatory and/or calendar.
d) to mark the locations of the 12 signs of the zodiac (Taurus, Libra, Sagittarius, Leo, Ares, Pisces, Gemini, Virgo, Scorpius, Cancer, Capricornus, and Aquarius).
e) to mark the location of Pluto on the sky.

18. Which of the following is true about Venus, as observed from the Earth through a small telescope?
a) it always looks like a crescent moon.
b) it goes through phases like the moon, but its angular size varies dramatically with phase, being largest during the full phase.
c) it goes through phases like the moon, but its angular size varies dramatically with phase, being smallest during the full phase.
d) it goes through phases like the moon, but its angular size remains constant with phase.
e) it does not have phases.

19. When using the lunar eclipse method to determine the relative size of the Earth and the Moon, it is assumed:
a) the angle between the Sun, Moon, and Earth is exactly 90 degrees during a lunar eclipse.
b) the distance between the Earth and the Sun, and between the Moon and the Earth, are the same.
c) the Sun is close to the Earth, so the Sun's light rays diverge, and the diameter of the Earth's shadow is 4 times bigger than that of the Earth.
d) the Sun is far away from the Earth, so the Sun's light rays are parallel, and the diameter of the Earth's shadow is the same size as that of the Earth.
e) at a given time, the angle between the zenith and the Sun is the same for every observer on Earth.

20. Ball A has a mass of two kilograms. Ball B has a mass of four kilograms. They are hit with a bat with the same force.
a) The subsequent acceleration of Ball A is half as much as that of Ball B.
b) The subsequent acceleration of Ball A is twice as much as that of Ball B.
c) The subsequent acceleration of Ball A is four times that of Ball B.
d) The subsequent acceleration of Ball A is the same as that of Ball B.
e) The velocity of Ball A and Ball B does not change.

21. The tendency of an object to resist a change in its motion is called:
a) weight. b) inertia. c) synodic period. d) precession. e) parallax.

22. Tycho Brahe is best known for:
a) His telescopic observations of the moon, Sun, and planets.
b) His accurate observations over many years of the positions of the stars and planets.
c) His detailed calculations of the orbits of the planets around the Sun.
d) His calculation of the diameter of the Earth using measurements of the angle between the Sun and the zenith at two locations on Earth.
e) His advocacy of the Sun-Centered Universe model.

23. The four largest moons of Jupiter were discovered by:
a) Newton. b) Copernicus. c) Tycho. d) Galileo. e) Eratosthenes.

24. Epicycles were invented by ancient Greek astronomers to:
a) explain why the constellations change as one moves north or south on the Earth.
b) measure the relative size of the Earth and the Moon.
c) measure the relative size of the Earth and the Sun.
d) support a Sun-centered model of the Universe.
e) account for the retrograde motion of the planets in an Earth-centered Universe.

25. Precession of the Earth's poles was first discovered:
a) by Galileo.
b) by Tycho.
c) by Kepler.
d) by Copernicus.
e) by ancient Greek and Chinese astronomers.

26. If you dropped a 10 lb weight, a 2 ounce pencil, and a 1 ounce pea at the same time, from the same height above the floor, which would hit the floor first (neglect air resistance)?
a) The weight.
b) The pea.
c) the pencil.
d) they would all hit at the same time.
e) the weight and the pencil would hit at the same time, the pea later.

27. The Earth is 81 times more massive than the Moon. Therefore, the gravitational force that the Moon exerts on the Earth is:
a) equal to the gravitational force the Earth exerts on the Moon.
b) One quarter the gravitational force the Earth exerts on the Moon.
c) 1/81 times the gravitational force the Earth exerts on the Moon.
d) Twice the gravitational force the Earth exerts on the Moon.
e) Eighty-one times the gravitational force the Earth exerts on the Moon.

28. Kepler's Third Law, P² = a³, means that:
a) a planet's period does not depend upon the eccentricity of its orbit.
b) all orbits with the same semi-major axis have the same period.
c) the period of a planet does not depend upon its mass.
d) planets that are farther from the Sun move at slower average speeds than nearer planets.
e) all of the above.

29. He discovered that the orbits of planets are ellipses.
a) Tycho Brahe.
b) Copernicus.
c) Kepler.
d) Galileo.
e) Ptolemy.

30. Kepler as a young man was an assistant of:
a) Galileo.
b) Ptolemy.
c) Newton.
d) Tycho Brahe.
e) Copernicus.

31. Kepler is best known for:
a) His telescopic observations of the Sun, moon, and planets.
b) His accurate observations over many years of the positions of the stars and planets.
c) His detailed calculations of the orbits of the planets around the Sun.
d) His calculation of the diameter of the Earth.
e) His book entitled `On the Revolution of the Celestial Sphere'

32. He discovered what we now call Newton's first law of motion:
a) Tycho Brahe.
b) Copernicus.
c) Kepler.
d) Galileo.
e) Ptolemy.

33. Which of the following was NOT observed by Galileo?
a) craters on the Moon.
b) stellar parallax.
c) sunspots.
d) Jupiter's moons.
e) phases of Venus.

34. Newton's Second Law of Motion tells us that the net force applied to an object equals its:
a) mass times energy.
b) momentum times velocity.
c) mass times velocity.
d) energy times acceleration.
e) mass times acceleration.

35. If your mass is 60 kg on the Earth, what would your mass be on the Moon?
a) 10 kg.
b) 20 kg.
c) 30 kg.
d) 60 kg.
e) 120 kg.

36. The definition of an ellipse states:
a) the difference in distances between any point on the ellipse and two fixed points remain constant.
b) the distance between any point on the ellipse and two fixed points always maintain the same ratio to each other.
c) the sum of the distances from any point on the ellipse to two other fixed points remains constant.
d) the distance from any point on the ellipse to a single fixed point is constant.
e) the long axis of an ellipse is always twice as big as the short axis.

37. Chinese astronomical records go back about 4000 years. Using these records, ancient Chinese astronomers were able to measure:
a) the parallax shift of stars caused by the Earth's motion around the Sun.
b) the precession of the Earth's poles.
c) the orbital period of Neptune around the Sun.
d) the orbital period of Jupiter's moons around Jupiter.
e) all of the above.

38. Eratosthenes measured the physical diameter of the Earth by:
a) measuring the shadow of the Earth on the Moon.
b) measuring the angle between the Sun and the Moon on the sky during a first quarter moon.
c) measuring the angle between the zenith and the Sun at two locations on Earth at the same time.
d) making many years of accurate measurements of the planet's locations in the sky.
e) comparing the positions of stars with positions recorded in old astronomical records.

39. In Kepler's Third Law, P² = a³, the `a' represents:
a) the acceleration of a planet due to the gravitational force of the Sun.
b) half of the long axis of the planet's orbit around the Sun.
c) the distance between the planet and the Sun, when the planet is closest to the Sun in its orbit.
d) the acceleration of falling objects on Earth.
e) the angle between the zenith and the Sun at noon.

40. The Dresden Codex is:
a) A book written by Ptolemy, that summarizes ancient Greek astronomical knowledge.
b) A Mayan manuscript dated about 1250 A.D., which included astronomical information.
c) A book written by Copernicus, advocating the Sun-centered Universe model.
d) Ancient Chinese astronomical records describing the precession of the Earth's poles.
e) A large rock formation in northern Wyoming, believed to have been used as an calendar and/or astronomical observatory.

41. Asteroids Ceres and Davida orbit the Sun at average distances of 2.77 A.U. and 3.19 A.U., respectively. Therefore:
a) Ceres' orbital period relative to the stars will be less than that of Davida.
b) Ceres' orbital period relative to the stars will be the same as that of Davida.
c) Ceres' orbital period relative to the stars will be larger than that of Davida.
d) Their orbital periods depend upon their masses, which are unknown.
e) They both have an orbital period of 1 year.

42. If you observed a given star two nights in a row, at exactly the same time, the difference in its position on the sky between the two nights would be:
a) 1 degree.
b) 30 degrees.
c) 60 degrees.
d) 90 degrees.
e) 180 degrees.

43. The Almagest is:
a) An ancient temple in Mexico where human sacrifice may have been practiced.
b) A book written by Copernicus, which supported the heliocentric Universe model.
c) A book written by Ptolemy, that summarized ancient Greek astronomical knowledge.
d) A Mayan manuscript dated to about 1250 AD, which included astronomical information.
e) A book written by Galileo, which described his astronomical observations and was subsequently banned.

44. He was the first person to see the phases of Venus.
a) Kepler.
b) Anaxagoras.
c) Tycho Brahe.
d) Eratosthenes.
e) Galileo.

45. Ball A and Ball B were both hit by a bat with the same force. Ball A accelerates 10 times faster than Ball B. This means:
a) Ball A is 10 times more massive than Ball B.
b) Ball A is 1/10th as massive as Ball B.
c) Ball A and Ball B have the same mass.
d) Ball A is 100 times more massive than Ball B.
e) Ball A is 1/100th as massive as Ball B.

46. The Big Horn Medicine Wheel is in:
a) Mexico.
b) Great Britian.
c) Greece.
d) the United States.
e) China.

47. A new comet is discovered, with a semi-major axis of its orbit around the Sun of 18 AU. What is its sidereal period?
a) 18 years.
b) The square root of 18 = 4.2 years.
c) 18² = 324 years.
d) 18³ = 5832 years.
e) the square root of 18³ = 76 years.

48. Which of the following scientists promoted a geocentric Universe model?
a) Aristotle.
b) Aristarchus.
c) Copernicus.
d) Galileo.
e) Kepler.

49. The figure on the right shows a planet's orbit around the Sun. In this Figure, areas 1 and 3 are the same, but area 2 is larger. The time for the planet to travel between points A and B is:
a) Larger than the time it takes to go from D to E, and smaller than the time it takes to go from B to C.
b) Smaller than the time it takes to go from D to E, but larger than the time it takes to go from B to C.
c) The same as the time it takes to go from D to E, but smaller than the time it takes to go from B to C.
d) The same as both the time it takes to go from D to E, and the time it takes to go from B to C.
e) Larger than the time it takes to go from D to E, and also larger than the time it takes to go from B to C.

50. The size of the Earth was first measured by:
a) Eratosthenes.
b) Aristotle.
c) Anaxagoras.
d) Galileo.
e) Hipparchus.

51. Newton's Third Law, in mathematical form, states:
a) F = MA.
b) P² = a³.
c) P³ = a².
d) F₁ = F₂.
e) p is proportional to 1/D

52. The planets orbiting the Sun:
a) travel in perfect circles, at constant velocity.
b) travel in ellipses, at constant velocity.
c) move in `circles within circles': they travel in small circles, with the center of the circle following a circular path around the Sun.
d) are constantly being accelerated.
e) are not accelerated.

53. The modern magnitude system of measuring the brightnesses of stars was invented by:
a) Aristotle.
b) Anaxagoras.
c) Hipparchus.
d) Aristarchus.
e) Eratosthenes.

54. The first ancient Greek scientist to observe precession was:
a) Aristotle.
b) Anaxagoras.
c) Hipparchus.
d) Aristarchus.
e) Eratosthenes.

55. Stellar parallax was first observed:
a) by Aristotle.
b) by Anaxagoras.
c) by Galileo.
d) by Hipparchus.
e) in the 1800's.

56. The book `The Almagest' was written by:

a) Newton.
b) A Mayan astronomer.
c) Copernicus.
d) Eratostenes.
e) Ptolemy.

57. Which of the following ancient Greek astronomers supported the heliocentric model of the Universe?
a) Aristarchus.
b) Anaxagoras.
c) Hipparchus.
d) Ptolemy.
e) Aristotle.

58. If your weight is 150 lbs on the Earth, what would your weight be on the Moon?
a) 900 lbs.
b) 150 lbs.
c) 25 lbs.
d) 1.5 lbs.
e) 0 lbs.

59. The Sun is 330,000 times more massive than the Earth. Therefore, the acceleration of the Sun caused by the gravitational pull of the Earth is:
a) equal to the acceleration of the Earth caused by the Sun.
b) 330,000 times the acceleration of the Earth caused by the Sun.
c) 1/330,000 times the acceleration of the Earth caused by the Sun.
d) 1/330,000² times the acceleration of the Earth caused by the Sun.
e) the Earth does not cause the Sun to accelerate.

60. Whose data was used after his death to show that the orbits of planets are ellipses?
a) Tycho Brahe.
b) Galileo.
c) Kepler.
d) Copernicus.
e) Ptolemy.

61. An asteroid orbiting the Sun with a sidereal period of 2 years has an orbital semi-major axis of:
a) the square root of 2 = 1.41.
b) the cube root of 4 = 1.59.
c) 2.
d) the square root of 8 = 2.83.
e) 8.

62. The Big Horn Medicine Wheel:
a) is described in the Dresden Codex.
b) is described in the Almagest.
c) is located in Great Britian.
d) is located in the ancient city of Babylon, in modern day Iraq.
e) may have been used as an astronomical observatory and/or calendar.

63. Who first concluded, based on experiments, that falling objects fall at the same rate, independent of their mass, in the absence of air resistance?
a) Galileo.
b) Newton.
c) Aristotle.
d) Copernicus.
e) Kepler.

64:. Aristotle:
a) Supported the heliocentric model of the Universe.
b) Discovering the precession of the Earth's poles.
c) Supported the spherical Earth theory.
d) Suggested that planets orbit the Sun in ellipses, not circles.
e) wrote the Almagest.

65. The equation P² = a³ is credited to:
a) Kepler.
b) Galileo.
c) Newton.
d) Tycho Brahe.
e) Hipparchus.

66. The figure on the right shows a planet's orbit around the Sun. At which point in the orbit is the planet moving fastest?
a) A.
b) B.
c) C.
d) D.
e) It is moving at the same speed at all positions in its orbit.

67. Which of the following phenomenon was not successfully observed until the 1800's?
a) stellar parallax.
b) the precession of the Earth's poles.
c) the phases of Venus.
d) the moons of Jupiter.
e) the retrograde motion of the planets.

68. Newton's Law of Universal Gravitation can be written mathematically as:
a) F = GM₁M₂/R²
b) F = GM₁/M₂R²
c) F = GM₁M₂/R
d) F = GM₁M₂R²
e) F = M₁M₂/GR²

69. If the distance between the Earth and the Moon increased by a factor of 8, how would the gravitational force between them change?
a) It would stay the same.
b) It would increase by a factor of 8.
c) It would decrease by a factor of 8.
d) It would increase by a factor of 64.
e) It would decrease by a factor of 64.

70. According to Newton's Laws of Motion, if no force acts on a moving planet it will:
a) stop moving.
b) move in a straight line at constant speed.
c) move on a circular path at constant speed.
d) slow down.
e) speed up.

71. Newton's 3rd Law of Motion states:
a) For every action, there is an equal and opposite action.
b) Objects at rest tend to remain at rest, objects in motion tend to remain in motion, unless acted upon by a force.
c) F = MA.
d) P² = a³.
e) the line connecting a planet to the Sun sweeps out equal areas in equal times.

72. Who wrote the book `On the Revolution of the Celestial Sphere', which outlined the arguments for the heliocentric model of the Universe?
a) Eratosthenes.
b) Copernicus.
c) Anaxagoras.
d) Ptolemy.
e) The ancient Mayans.

73. Who was Tycho Brahe's assistant?
a) Kepler.
b) Copernicus.
c) Newton.
d) Galileo.
e) Hipparchus.

74. Why are there 360 degrees in a circle?

a) Aristotle divided the circle into 360 parts because there were 60 teachers in his school, each of whom had 60 students.
b) This concept was inherited from the Mayans.
c) Hipparchus's catalog of stars contained 360 stars.
d) The ancient Babylonian calendar had 360 days.
e) This idea was adopted from the ancient Chinese, who found 360 constellations in the sky.

75. Aristotle:

a) Argued that the Earth was flat.
b) Measured the diameter of the Earth.
c) Wrote the book `the Almagest'.
d) Wrote the book `on the Revolution of the Celestial Sphere'.
e) Supported the geocentric model of the Universe.

76. Which of the following ancient Greek scholars first measured the diameter of the Earth by measuring the angle between the Sun and the zenith at two locations on the Earth at the same time?
a) Hipparchus.
b) Aristotle.
c) Aristarchus.
d) Eratosthenes.
e) Ptolemy.

77. Which of the following ancient Greek scholars argued that the Earth was flat?
a) Aristotle.
b) Anaxagoras.
c) Eratosthenes.
d) Pythagoras.
e) None of the above.

78. The `modern' explanation of the phases of the Moon that we use today is credited to:
a) Eratosthenes.
b) Hipparchus.
c) Anaxagoras.
d) Copernicus.
e) Galileo.

79. The large ancient `circle and spokes' made up of stones in northern Wyoming, thought to have astronomical and/or religious significance, is called:

a) Stonehenge.
b) The Venus Calendar.
c) The Big Horn Medicine Wheel.
d) The Revolution of the Celestial Sphere.
e) The Almagest.

80. If the distance between the Earth and the Moon increased by a factor of 3, how would the gravitational force between them change?

a) It would stay the same.
b) It would increase by a factor of 3.
c) It would decrease by a factor of 3.
d) It would increase by a factor of 3² = 9.
e) It would decrease by a factor of 3² = 9.

81. The `circle within a circle', used to explain the retrograde motion of the planets in the geocentric model of the Universe, is called the:

a) epicycle.
b) almagest.
c) celestial wheel.
d) codex.
e) parallax cycle.

82. The Sun is 330,000 times more massive than the Earth. The force the Sun exerts on the Earth is:
a) equal to the force the Earth exerts on the Sun.
b) 330,000 times the force the Earth exerts on the Sun.
c) 1/330,000 times the force the Earth exerts on the Sun.
d) 1/330,000² times the force the Earth exerts on the Sun.
e) 330,000² times the force the Earth exerts on the Sun.

83. Which of the following is NOT attributed to Galileo?
a) Developed the universal gravitation equation.
b) First to use a telescope to study astronomical objects.
c) Discovered the four large moons of Jupiter.
d) Determined that objects of different mass fall at the same rate in the absence of air resistance.
e) First to observe the phases of Venus.

84. Which of the following is the title of an ancient book dealing with astronomical concepts?

a) The Dresden Codex.
b) The Almagest.
c) On the Revolution of the Celestial Sphere.
d) All of the above.
e) None of the above.

85. Which of the following ancient Greek scholars compiled the book `The Almagest', which summarized ancient Greek astronomical knowledge?
a) Hipparchus.
b) Aristotle.
c) Aristarchus.
d) Eratosthenes.
e) Ptolemy.

86. Which of the following scientists supported a Geocentric model of the Universe?
a) Kepler.
b) Tycho Brahe.
c) Galileo.
d) Newton.
e) Copericus.

87. Aristotle:
a) Suggested the Earth was flat.
b) Determined the relative size of the Sun, the Earth, and the Moon.
c) Made the first reasonably accurate estimate of the size of the Earth.
d) Supported the idea that the Earth was a sphere.
e) Discovered the moons of Jupiter.

88. If the distance between the Earth and the Moon decreased by a factor of 5, how would the gravitational force between them change?

a) It would stay the same.
b) It would increase by a factor of 5.
c) It would decrease by a factor of 5.
d) It would increase by a factor of 5² = 25.
e) It would decrease by a factor of 5² = 25.

89. Which of the following scientists did *NOT* use epicycles to describe the orbits of the planets?
a) Kepler
b) Apollonius.
c) Copernicus.
d) Hipparchus.
e) Ptolemy.

90. The Sun is 3500 times more massive than Saturn. The gravitational force the Sun exerts on Saturn is:
a) equal to the force Saturn exerts on the Sun.
b) 3500 times the force Saturn exerts on the Sun.
c) 1/3500 times the force Saturn exerts on the Sun.
d) 1/3500² times the force Saturn exerts on the Sun.
e) 3500² times the force Saturn exerts on the Sun.

91. The ancient Greek scientist Eratosthenes is best known for:
a) the `modern' explanation of the phases of the Moon.
b) the `modern' explanation of eclipses.
c) being the first person to suggest the Earth is a sphere.
d) writing the book `The Almagest'.
e) measuring the diameter of the Earth.

92. Tycho Brahe:
a) Wrote the book `On the Revolution of the Celestial Sphere'.
b) Wrote the book `The Almagest'.
c) Was the first person to use a telescope to study astronomical objects.
d) Was the first person to suggest that planets orbit the Sun in ellipses.
e) None of the above.

93. Isaac Newton:
a) Was the first person to observe the phases of Venus.
b) Was the first person to realize that falling objects fall at the same rate, in a vacuum.
c) Was the first person to discover the moons of Jupiter.
d) Came up with a mathematical formula for the gravitational force between two objects.
e) Was the first person to suggest that planets orbit the Sun in ellipses.

94. Which of the following was NOT accomplished by an ancient Greek scientist?
a) Measured stellar parallax.
b) Measured the diameter of the Earth.
c) Discovered the precession of the Earth's poles.
d) Measured the relative size of the Earth and the Moon.
e) Measured the relative size of the Sun and the Moon.

95. The equation P² = a³, where P is the sidereal period of a planet and a the semi-major axis of its orbit, is known as:
a) Kepler's Third Law.
b) Kepler's First Law.
c) Newton's Third Law.
d) Newton's Law of Universal Gravitation.
e) Copernicus' Law of Planetary Orbits.

96. What is the difference between velocity and speed?
a) Speed has units of km/s, while velocity has units of km/s².
b) Velocity has units of km/s, while speed has units of km/s².
c) Velocity has units of km/s², while speed has units of km/s³.
d) Velocity is a change in speed per time.
e) Velocity has a direction associated with it.

97. If you were on Mars:
a) your weight would be the same as on Earth, but your mass would be different.
b) your mass would be the same as on Earth, but your weight would be different.
c) your mass and weight would be the same as on Earth.
d) both your mass and your weight would differ from those on Earth.
e) your mass and weight would be the same as on Earth, but your inertia would be different.

98. An epicycle is:
a) a measure of how elongated an ellipse is.
b) a `wobble' in the Earth's axis, caused by the uneven gravitational pull on the Earth by the Sun and Moon due to the Earth's tilt and equatorial bulge.
c) a `circle within a circle' orbit of the planets around the Earth, invented to explain the retrograde motion of the planets within the geocentric model of the Universe.
d) the apparent back-and-forth shift of nearby stars relative to background stars, due to the Earth's orbit around the Sun.
e) a large `wheel' of stones found in North America, dating to ancient times.

99. The rule of physics that states `For every force, there is an equal and opposite force' is known as:
a) Kepler's First Law.
b) Newton's Second Law.
c) Newton's Third Law.
d) The Law of Inertia.
e) Galileo's Law.

100. If the mass of the Earth suddenly tripled, how would the gravitational force between the Earth and the Moon change?
a) it would increase by a factor of nine.
b) it would increase by a factor of three.
c) it would decrease by a factor of three.
d) it would decrease by a factor of nine.
e) it would stay the same.

101. In what way did Kepler's model of the Universe differ from that of Copernicus?

a) Copernicus supported a Geocentric model, while Kepler argued for a Heliocentric model.
b) Kepler supported a Geocentric model, while Copernicus argued for a Heliocentric model.
c) They both supported a model in which the Earth is the center of the Universe, but in Kepler's model, the planets orbit the Sun instead of the Earth.
d) They both supported a Heliocentric model, but in Kepler's model, the planets move on elliptical orbits, while in the model of Copernicus the planets orbit the Sun in 'circles within circles'.
e) They both supported a model in which the Earth is the center of the Universe, but in Copernicus' model, the planets orbit the Sun instead of the Earth.

102. The `modern' explanation of the phases of the Moon that we use today is credited to:
a) Copernicus.
b) Galileo.
c) Tycho Brahe.
d) Anaxagoras.
e) Aristotle.

103. The physical diameter of the Earth was first accurately determined by:
a) Measuring the angle between the Sun and the Moon during a first quarter moon.
b) Timing a lunar eclipse.
c) Measuring the curvature of the shadow of the Earth on the Moon during a lunar eclipse.
d) By Christopher Columbus, when sailing to America.
e) Measuring the angle between the Sun and the zenith at two locations on the Earth at the same time.

104. If the distance between the Earth and the Sun increased by a factor of 10 to 10 A.U., how would the gravitational force between them change?

a) It would stay the same.
b) It would increase by a factor of 10.
c) It would decrease by a factor of 10.
d) It would increase by a factor of 10² = 100.
e) It would decrease by a factor of 10² = 100.

105. Kepler's 2nd Law refers to:
a) The speed of a planet in its orbit around the Sun.
b) The tendency of objects to keep moving in a straight line, if no force acts upon them.
c) The period of a planet's orbit, in terms of the semi-major axis of its orbit.
d) The shape of a planet's orbit.
e) The fact that falling objects tend to fall at the same rate, independent of their mass.

106. In the Bighorn National Forest in northern Wyoming, there is an ancient `ring and spokes' made of rocks, which is thought to have astronomical significance. This structure is called a/an:
a) celestial sphere.
b) celestial wheel.
c) epicycle circle.
d) medicine wheel.
e) eccentric wheel.

107. The mass of an object:
a) depends upon the gravitational field the object is in.
b) is proportional to the inertia of the object.
c) is the same as the weight of the object.
d) affects how fast the object falls in a vacuum, with more massive objects falling faster.
e) is measured in pounds.

108. Which of the following observations was NOT made until the 1800's?
a) The retrograde motion of the planets.
b) Stellar parallax.
c) The parallax of the Moon.
d) The discovery of the moons of Jupiter.
e) The discovery of the phases of Venus.

109. Pluto has a mass approximately 6 times that of its moon Charon. The gravitational force that Pluto exerts on Charon is therefore:
a) 6 times that exerted on Pluto by Charon.
b) 1/6th that exerted on Pluto by Charon.
c) 36 times that exerted on Pluto by Charon.
d) 1/36th that exerted on Pluto by Charon.
e) the same as that exerted on Pluto by Charon.

110. Which of the following is a unit of mass?
a) slug.
b) pound.
c) Newton.
d) meter/second².
e) meter/second.

111. Which of the following scientists proposed a model of the Universe in which the Earth does not move, the Sun goes around the Earth, and the other planets go around the Sun?

a) Copernicus.
b) Galileo.
c) Kepler.
d) Tycho Brahe.
e) Ptolemy.

112. Eratosthenes was:
a) A supporter of the heliocentric model of the Universe.
b) The first person to make a reasonably accurate estimate of the size of the Earth.
c) The person who invented the epicyclic model of planetary motion.
d) The first person to measure stellar parallax.
e) The first person to use a telescope for astronomical observations.

113. Which of the following scientists thought the Earth was flat?
a) Ptolemy.
b) Aristotle.
c) Eratosthenes.
d) Aristarchus.
e) None of the above.

114. When Venus is in its crescent phase:

a) It has its largest angular size.
b) It has its smallest angular size.
c) Its angular size is in-between that of the full phase and that of the quarter phase.
d) The angular size of Venus is always about the same, independent of its phase.
e) Venus does not go through phases; it always looks like a full disk in the sky.

115. Which of the following scientists did not include epicycles in their description of planetary motion?
a) Ptolemy.
b) Copernicus.
c) Kepler.
d) Hipparchus.
e) None of the above scientists included epicycles in their models of planetary motion.

116. If the distance between the Earth and the Sun increases from 1 A.U. to 3 A.U., how would the gravitational force between them change?

a) It would stay the same.
b) It would increase by a factor of 3.
c) It would decrease by a factor of 3.
d) It would increase by a factor of 3² = 9.
e) It would decrease by a factor of 3² = 9.

117. The square of the sidereal period of a planet is proportional to the cube of the semi-major axis of its orbit. What is the name of this rule?
a) Kepler's Third Law.
b) Newton's Third Law.
c) The First Law of Copernicus.
d) Kepler's First Law.
e) Newton's Second Law.

118. Kepler is best known for:
a) Inventing the epicycle model of planetary motion.
b) Showing that all objects fall at the same rate in a vacuum, independent of the mass.
c) Concluding that planets orbit the Sun in ellipses, not circles.
d) Discovering the phases of Venus.
e) Supporting a model of the Universe in which the Earth is stationary, the Sun orbits the Earth, and the other planets orbit the Sun.

119. What is the mathematical relationship between the stellar parallax of a nearby star (P) and its distance (D)?
a) P is proportional to D.
b) P is proportional to 1/D.
c) P is proportional to D².
d) P is proportional to 1/D².
e) P² is proportional to D³.

120. What is the eccentricity of an ellipse that has been squashed all the way down to a straight line?
a) 0.
b) 1.
c) 0.5
d) -1.
e) -0.5.

121. Halley's Comet has a very elongated orbit. Its closest point to the Sun is inside the orbit of Venus, and its most distant location is outside the orbit of Neptune. When is Halley's comet moving the fastest in its orbit, in km/s?

a) At its farthest distance from the Sun, outside the orbit of Neptune.
b) When it is closest to the Sun.
c) When it crosses the orbit of Jupiter.
d) When it passes Mars.
e) It always moves at the same speed.

122. The Big Horn Medicine Wheel is in:
a) England.
b) Peru.
c) Wyoming.
d) Greece.
e) France.

123. What is the correct chronological order for the birth of the following scientists, in order from the earliest to the latest?
a) Aristotle, Ptolemy, Tycho, Kepler.
b) Ptolemy, Tycho, Aristotle, Kepler.
c) Tycho, Aristotle, Ptolemy, Kepler.
d) Aristotle, Ptolemy, Kepler, Tycho.
e) Ptolemy, Aristotle, Kepler, Tycho.

124. In ancient Greek astronomy, an `epicycle' is:
a) the time it takes the Moon to go through its full set of phases.
b) the time it takes a star to appear to orbit the Earth.
c) the back-and-forth motion of a nearby star in the sky relative to the background, due to the Earth's orbit around the Sun.
d) one of the two foci of an ellipse.
e) the `circles within circles' that planets travel along in their orbits around the Earth.

125. In the metric system, a Newton is a unit of:
a) velocity.
b) acceleration.
c) speed.
d) force.
e) mass.

126. If two stars are separated by a distance R, what is the relationship between R and the gravitational force F between the two stars?
a) F is proportional to R.
b) F is proportional to 1/R.
c) F is proportional to R².
d) F is proportional to 1/R²
e) F is proportional to 1/R³

127. Which of the following astronomical instruments did Tycho Brahe NOT have access to?
a) Astrolabe.
b) Quadrant.
c) Sextant.
d) Telescope.
e) Armillary Sphere.

128. Which of the following is a unit of acceleration?
a) meters/second.
b) Newtons/second.
c) meters/second².
d) feet/hour.
e) light years/decade.

129. Aristarchus determined the relative size of the Earth and the Moon by:
a) observing the angle between the Moon and the Sun in the sky.
b) observing the angle between the Moon and the zenith on the summer solstice.
c) observing the Moon during a solar eclipse.
d) observing the Moon during a lunar eclipse.
e) measuring the shadow of the Moon on the Earth.

130. Isaac Newton is credited with being the first person to:
a) realize that the orbits of planets are ellipses.
b) introduce the concept of inertia.
c) make an accurate estimate of the radius of the Earth.
d) explain solar eclipses.
e) obtain an equation relating the acceleration of an object to the force applied to the object and the mass of the object.

Answers: 1a, 2d, 3e, 4d, 5a, 6a, 7a, 8a, 9a, 10e, 11d, 12d, 13e, 14d, 15b, 16c, 17c, 18c, 19d, 20b, 21b, 22b, 23d, 24e, 25e, 26d, 27a, 28e, 29c, 30d, 31c, 32d, 33b, 34e, 35d, 36c, 37b, 38c, 39b, 40b, 41a, 42a, 43c, 44e, 45b, 46d, 47e, 48a, 49c, 50a, 51d, 52d, 53c, 54c, 55e, 56e, 57a, 58c, 58c, 59c, 60a, 61b, 62e, 63a, 64c, 65a, 66a, 67a, 68a, 69e, 70b, 71a, 72b, 73a, 74d, 75e, 76d, 77e, 78c, 79c, 80e, 81a, 82a, 83a, 84d, 85e, 86b, 87d, 88d, 89a, 90a, 91e, 92e, 93d, 94a, 95a, 96e, 97b, 98c, 99c, 100b, 101d, 102d, 103e, 104e, 105a, 106d, 107b, 108b, 109e, 110a, 111d, 112b, 113e, 114a, 115c, 116e, 117a, 118c, 119b, 120b, 121b, 122c, 123a, 124e, 125d, 126d, 127d, 128c, 129c, 130e.