Astronomy A BEGINNER’S GUIDE TO THE UNIVERSE EIGHTH EDITION CHAPTER The Copernican Revolution Clickers © 2017 Pearson Education, Inc Question Mars, Jupiter, and Saturn show retrograde motion because a) b) planets move on epicycles planets orbit the Sun in the same direction c) d) e) © 2017 Pearson Education, Inc Earth moves faster in its orbit they are closer than Uranus they rotate quickly on their axes Question Mars, Jupiter, and Saturn show retrograde motion because a) b) planets move on epicycles planets orbit the Sun in the same direction c) d) e) Earth moves faster in its orbit they are closer than Uranus they rotate quickly on their axes Explanation: As Earth overtakes and “passes” the outer planets, they seem to slow down and then reverse direction © 2017 Pearson Education, Inc Question How did the geocentric model account for day and night on Earth? a) b) c) The Earth rotated The Sun rotated The geocentric model couldn’t account for day and night d) e) © 2017 Pearson Education, Inc The Earth revolved around the Sun The Sun orbited Earth Question How did the geocentric model account for day and night on Earth? a) b) c) The Earth rotated The Sun rotated The geocentric model couldn’t account for day and night d) e) The Earth revolved around the Sun The Sun orbited Earth Explanation: The geocentric model held that the Earth was motionless in the center of the universe © 2017 Pearson Education, Inc Question Epicycles were used in Ptolemy’s model to explain why a) b) c) d) e) planets moved in the sky Earth was at the center retrograde motion occurred Earth wobbled on its axis inner planets were always seen near the Sun © 2017 Pearson Education, Inc Question Epicycles were used in Ptolemy’s model to explain why a) b) c) d) e) planets moved in the sky Earth was at the center retrograde motion occurred Earth wobbled on its axis inner planets were always seen near the Sun Explanation: Planets were assumed to move uniformly on an epicycle, as it moved uniformly around Earth © 2017 Pearson Education, Inc Question The geocentric model was supported by Aristotle because of which of the following? a) b) c) d) e) © 2017 Pearson Education, Inc Stars don’t seem to show any parallax We don’t feel as though Earth moves Objects fall toward Earth, not the Sun We don’t see an enormous wind All of the above were valid reasons Question The geocentric model was supported by Aristotle because of which of the following? a) b) c) d) e) Stars don’t seem to show any parallax We don’t feel as though Earth moves Objects fall toward Earth, not the Sun We don’t see an enormous wind All of the above were valid reasons Explanation: 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 © 2017 Pearson Education, Inc Question The heliocentric model assumes that a) b) c) d) e) © 2017 Pearson Education, Inc planets move on epicycles Earth is the center of the solar system the stars move on the celestial sphere the Sun is the center of the solar system Earth’s axis wobbles over 26,000 years Question Copernicus’s heliocentric model was flawed because he a) b) c) d) e) assumed planets moved in ellipses didn’t know about Uranus and Neptune couldn’t account for gravity couldn’t explain retrograde motion didn’t assume planets moved in ellipses Explanation: Copernicus’s model still needed small epicycles to account for observed changes in planetary speeds © 2017 Pearson Education, Inc Question Who published the first astronomical observations made with a telescope? a) b) c) d) e) © 2017 Pearson Education, Inc Hipparchus Galileo Tycho Copernicus Kepler Question Who published the first astronomical observations made with a telescope? a) b) c) d) e) Hipparchus Galileo Tycho Copernicus Kepler Explanation: Galileo published the “Starry Messenger” in 1610, detailing his observations of the Moon, Jupiter’s moons, stars, and nebulae © 2017 Pearson Education, Inc Question Which of Galileo’s initial observations was most challenging to established geocentric beliefs? a) b) c) d) e) © 2017 Pearson Education, Inc Craters on the Moon Sunspots Lunar maria Satellites of Jupiter Stars of the Milky Way Question Which of Galileo’s initial observations was most challenging to established geocentric beliefs? a) b) c) d) e) Craters on the Moon Sunspots Lunar maria Satellites of Jupiter Stars of the Milky Way Explanation: 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 © 2017 Pearson Education, Inc Question 10 Which hero of the Renaissance postulated three “laws” of planetary motion? a) b) c) d) e) © 2017 Pearson Education, Inc Kepler Newton Galileo Tycho Brahe Copernicus Question 10 Which hero of the Renaissance postulated three “laws” of planetary motion? a) b) c) d) e) Kepler Newton Galileo Tycho Brahe Copernicus Explanation: 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 © 2017 Pearson Education, Inc Question 11 Kepler’s first law of planetary orbits states that a) b) c) d) © 2017 Pearson Education, Inc planets orbit the Sun orbits are noncircular orbits are elliptical in shape all of the above are stated Question 11 Kepler’s first law of planetary orbits states that a) b) c) d) planets orbit the Sun orbits are noncircular orbits are elliptical in shape all of the above are stated Explanation: 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 © 2017 Pearson Education, Inc Question 12 Earth is closer to the Sun in January From this fact, Kepler’s second law tells us that a) b) c) © 2017 Pearson Education, Inc Earth orbits slower in January Earth orbits faster in January Earth’s orbital speed doesn’t change Question 12 Earth is closer to the Sun in January From this fact, Kepler’s second law tells us a) b) c) Earth orbits slower in January Earth orbits faster in January Earth’s orbital speed doesn’t change Explanation: Kepler’s second law means that a planet moves faster when closer to its star © 2017 Pearson Education, Inc Question 13 Kepler’s third law relates a planet’s distance from the Sun and its orbital a) b) c) d) © 2017 Pearson Education, Inc speed period shape velocity Question 13 Kepler’s third law relates a planet’s distance from the Sun and its orbital Venus’s period = 225 days a) b) c) d) speed Venus’s axis = 0.7 AU period shape velocity Explanation: Kepler’s third law P = a means more distant planets orbit more slowly Earth’s period = 365 days Earth’s axis = AU © 2017 Pearson Education, Inc Question 14 Newton’s law of gravity states that the force between two objects a) b) c) d) © 2017 Pearson Education, Inc increases with distance depends on the state of matter (solid, liquid, or gas) can be attractive or repulsive increases with mass Question 14 Newton’s law of gravity states that the force between two objects a) b) c) d) increases with distance depends on the state of matter (solid, liquid, or gas) can be attractive or repulsive increases with mass Explanation: 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 © 2017 Pearson Education, Inc ... feel as though Earth moves Objects fall toward Earth, not the Sun We don’t see an enormous wind All of the above were valid reasons Explanation: Aristotle thought that if the Earth rotated and... elliptical in shape all of the above are stated Explanation: 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... the same direction c) d) e) Earth moves faster in its orbit they are closer than Uranus they rotate quickly on their axes Explanation: As Earth overtakes and “passes” the outer planets, they