{"id":98,"date":"2017-12-12T14:38:06","date_gmt":"2017-12-12T19:38:06","guid":{"rendered":"https:\/\/pressbooks.bccampus.ca\/astronomy1105dl\/chapter\/2-6-collaborative-group-activities-and-questions\/"},"modified":"2017-12-20T13:44:20","modified_gmt":"2017-12-20T18:44:20","slug":"2-6-collaborative-group-activities-and-questions","status":"publish","type":"chapter","link":"https:\/\/pressbooks.bccampus.ca\/astronomy1105dl\/chapter\/2-6-collaborative-group-activities-and-questions\/","title":{"raw":"2.7 Collaborative Group Activities and Questions","rendered":"2.7 Collaborative Group Activities and Questions"},"content":{"raw":"\n<section id=\"fs-id1170326170688\" class=\"group-activities\">\n<h1>Collaborative Group Activities<\/h1>\n<ol id=\"fs-id1170326314943\">\n<li>With your group, consider the question with which we began this chapter. How many ways can you think of to prove to a member of the \u201cFlat Earth Society\u201d that our planet is, indeed, round?<\/li>\n<li>Make a list of ways in which a belief in astrology (the notion that your life path or personality is controlled by the position of the Sun, Moon, and planets at the time of your birth) might be harmful to an individual or to society at large.<\/li>\n<li>Have members of the group compare their experiences with the night sky. Did you see the Milky Way? Can you identify any constellations? Make a list of reasons why you think so many fewer people know the night sky today than at the time of the ancient Greeks. Discuss reasons for why a person, today, may want to be acquainted with the night sky.<\/li>\n<li>Constellations commemorate great heroes, dangers, or events in the legends of the people who name them. Suppose we had to start from scratch today, naming the patterns of stars in the sky. Whom or what would you choose to commemorate by naming a constellation after it, him, or her and why (begin with people from history; then if you have time, include living people as well)? Can the members of your group agree on any choices?<\/li>\n<li>Although astronomical mythology no longer holds a powerful sway over the modern imagination, we still find proof of the power of astronomical images in the number of products in the marketplace that have astronomical names. How many can your group come up with? (Think of things like Milky Way candy bars, Eclipse and Orbit gum, or Comet cleanser.)<\/li>\n<\/ol>\n<\/section>\n<section id=\"fs-id1170326275940\" class=\"review-questions\">\n<h1>Review Questions<\/h1>\n<div class=\"exercise\" id=\"fs-id1170326051253\">\n<div class=\"problem\" id=\"fs-id1170326160367\">\n<p id=\"fs-id1170326098916\"><strong>1:<\/strong> From where on Earth could you observe all of the stars during the course of a year? What fraction of the sky can be seen from the North Pole?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326053402\">\n<div class=\"problem\" id=\"fs-id1170326189756\">\n<p id=\"fs-id1170326025588\"><strong>2:<\/strong> Give four ways to demonstrate that Earth is spherical.<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326226275\">\n<div class=\"problem\" id=\"fs-id1170326126213\">\n<p id=\"fs-id1170326275618\"><strong>3:<\/strong> Explain, according to both geocentric and heliocentric cosmologies, why we see retrograde motion of the planets.<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326454048\">\n<div class=\"problem\" id=\"fs-id1170326052958\">\n<p id=\"fs-id1170326130783\"><strong>4:<\/strong> In what ways did the work of Copernicus and Galileo differ from the views of the ancient Greeks and of their contemporaries?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326320724\">\n<div class=\"problem\" id=\"fs-id1170326204000\">\n<p id=\"fs-id1170326190029\"><strong>5:<\/strong> What were four of Galileo\u2019s discoveries that were important to astronomy?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326189344\">\n<div class=\"problem\" id=\"fs-id1170326244106\">\n<p id=\"fs-id1170326024454\"><strong>6:<\/strong> Explain the origin of the magnitude designation for determining the brightness of stars. Why does it seem to go backward, with smaller numbers indicating brighter stars?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326314036\">\n<div class=\"problem\" id=\"fs-id1170326066555\">\n<p id=\"fs-id1170326119333\"><strong>7:<\/strong> Ursa Minor contains the pole star, Polaris, and the asterism known as the Little Dipper. From most locations in the Northern Hemisphere, all of the stars in Ursa Minor are circumpolar. Does that mean these stars are also above the horizon during the day? Explain.<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326453293\">\n<div class=\"problem\" id=\"fs-id1170326141173\">\n<p id=\"fs-id1170326119377\"><strong>8:<\/strong> How many degrees does the Sun move per day relative to the fixed stars? How many days does it take for the Sun to return to its original location relative to the fixed stars?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326449708\">\n<div class=\"problem\" id=\"fs-id1170326118814\">\n<p id=\"fs-id1170326129646\"><strong>9:<\/strong> How many degrees does the Moon move per day relative to the fixed stars? How many days does it take for the Moon to return to its original location relative to the fixed stars?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326115529\">\n<div class=\"problem\" id=\"fs-id1170326290808\">\n<p id=\"fs-id1170326452150\"><strong>10:<\/strong> Explain how the zodiacal constellations are different from the other constellations.<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326334966\">\n<div class=\"problem\" id=\"fs-id1170326328600\">\n<p id=\"fs-id1170326276061\"><strong>11:<\/strong> The Sun was once thought to be a planet. Explain why.<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326323065\">\n<div class=\"problem\" id=\"fs-id1170326166043\">\n<p id=\"fs-id1170326074811\"><strong>12:<\/strong> Is the ecliptic the same thing as the celestial equator? Explain.<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326276910\">\n<div class=\"problem\" id=\"fs-id1170326243164\">\n<p id=\"fs-id1170326280677\"><strong>13:<\/strong> What is an asterism? Can you name an example?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326325438\">\n<div class=\"problem\" id=\"fs-id1170326205374\">\n<p id=\"fs-id1170326202153\"><strong>14:<\/strong> Why did Pythagoras believe that Earth should be spherical?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326279489\">\n<div class=\"problem\" id=\"fs-id1170326452840\">\n<p id=\"fs-id1170326166820\"><strong>15:<\/strong> How did Aristotle deduce that the Sun is farther away from Earth than the Moon?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326285675\">\n<div class=\"problem\" id=\"fs-id1170326335325\">\n<p id=\"fs-id1170326167111\"><strong>16:<\/strong> What are two ways in which Aristotle deduced that Earth is spherical?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326204421\">\n<div class=\"problem\" id=\"fs-id1170326021529\">\n<p id=\"fs-id1170326023932\"><strong>17:<\/strong> How did Hipparchus discover the wobble of Earth\u2019s axis, known as <em>precession<\/em>?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326125372\">\n<div class=\"problem\" id=\"fs-id1170326243233\">\n<p id=\"fs-id1170326272782\"><strong>18:<\/strong> Why did Ptolemy have to introduce multiple circles of motion for the planets instead of a single, simple circle to represent the planet\u2019s motion around the Sun?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326219829\">\n<div class=\"problem\" id=\"fs-id1170326243302\">\n<p id=\"fs-id1170326272140\"><strong>19:<\/strong> Why did Copernicus want to develop a completely new system for predicting planetary positions? Provide two reasons.<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326021484\">\n<div class=\"problem\" id=\"fs-id1170326133414\">\n<p id=\"fs-id1170326450680\"><strong>20:<\/strong> What two factors made it difficult, at first, for astronomers to choose between the Copernican heliocentric model and the Ptolemaic geocentric model?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326320087\">\n<div class=\"problem\" id=\"fs-id1170326186336\">\n<p id=\"fs-id1170326336432\"><strong>21:<\/strong> What phases would Venus show if the geocentric model were correct?<\/p>\n<\/div>\n<\/div>\n<\/section>\n<section id=\"fs-id1170326052774\" class=\"thought-questions\">\n<h1>Thought Questions<\/h1>\n<div class=\"exercise\" id=\"fs-id1170326118837\">\n<div class=\"problem\" id=\"fs-id1170326242732\">\n<p id=\"fs-id1170326217029\"><strong>22:<\/strong> Describe a practical way to determine in which constellation the Sun is found at any time of the year.<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326203149\">\n<div class=\"problem\" id=\"fs-id1170326203972\">\n<p id=\"fs-id1170326025880\"><strong>23:<\/strong> What is a constellation as astronomers define it today? What does it mean when an astronomer says, \u201cI saw a comet in Orion last night\u201d?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326243085\">\n<div class=\"problem\" id=\"fs-id1170326054296\">\n<p id=\"fs-id1170326169753\"><strong>24:<\/strong> Draw a picture that explains why Venus goes through phases the way the Moon does, according to the heliocentric cosmology. Does Jupiter also go through phases as seen from Earth? Why?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326067695\">\n<div class=\"problem\" id=\"fs-id1170326451668\">\n<p id=\"fs-id1170326121988\"><strong>25:<\/strong> Show with a simple diagram how the lower parts of a ship disappear first as it sails away from you on a spherical Earth. Use the same diagram to show why lookouts on old sailing ships could see farther from the masthead than from the deck. Would there be any advantage to posting lookouts on the mast if Earth were flat? (Note that these nautical arguments for a spherical Earth were quite familiar to Columbus and other mariners of his time.)<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326487969\">\n<div class=\"problem\" id=\"fs-id1170326216661\">\n<p id=\"fs-id1170326243256\"><strong>26:<\/strong> Parallaxes of stars were not observed by ancient astronomers. How can this fact be reconciled with the heliocentric hypothesis?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326450800\">\n<div class=\"problem\" id=\"fs-id1170326021605\">\n<p id=\"fs-id1170326177973\"><strong>27:<\/strong> Why do you think so many people still believe in astrology and spend money on it? What psychological needs does such a belief system satisfy?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326272237\">\n<div class=\"problem\" id=\"fs-id1170326119045\">\n<p id=\"fs-id1170326453270\"><strong>28:<\/strong> Consider three cosmological perspectives\u2014the geocentric perspective, the heliocentric perspective, and the modern perspective\u2014in which the Sun is a minor star on the outskirts of one galaxy among billions. Discuss some of the cultural and philosophical implications of each point of view.<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326324939\">\n<div class=\"problem\" id=\"fs-id1170326281687\">\n<p id=\"fs-id1170326074576\"><strong>29:<\/strong> The north celestial pole appears at an altitude above the horizon that is equal to the observer\u2019s latitude. Identify Polaris, the North Star, which lies very close to the north celestial pole. Measure its altitude. (This can be done with a protractor. Alternatively, your fist, extended at arm\u2019s length, spans a distance approximately equal to 10\u00b0.) Compare this estimate with your latitude. (Note that this experiment cannot be performed easily in the Southern Hemisphere because Polaris itself is not visible in the south and no bright star is located near the south celestial pole.)<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326205241\">\n<div class=\"problem\" id=\"fs-id1170326320170\">\n<p id=\"fs-id1170326334750\"><strong>30:<\/strong> What were two arguments or lines of evidence in support of the geocentric model?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326201261\">\n<div class=\"problem\" id=\"fs-id1170326024540\">\n<p id=\"fs-id1170326150186\"><strong>31:<\/strong> Although the Copernican system was largely correct to place the Sun at the center of all planetary motion, the model still gave inaccurate predictions for planetary positions. Explain the flaw in the Copernican model that hindered its accuracy.<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326077736\">\n<div class=\"problem\" id=\"fs-id1170326055981\">\n<p id=\"fs-id1170326222748\"><strong>32:<\/strong> During a retrograde loop of Mars, would you expect Mars to be brighter than usual in the sky, about average in brightness, or fainter than usual in the sky? Explain.<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326314189\">\n<div class=\"problem\" id=\"fs-id1170326339148\">\n<p id=\"fs-id1170326204570\"><strong>33:<\/strong> The Great Pyramid of Giza was constructed nearly 5000 years ago. Within the pyramid, archaeologists discovered a shaft leading from the central chamber out of the pyramid, oriented for favorable viewing of the bright star Thuban at that time. Thinking about Earth\u2019s precession, explain why Thuban might have been an important star to the ancient Egyptians.<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326098990\">\n<div class=\"problem\" id=\"fs-id1170326098992\">\n<p id=\"fs-id1170326334665\"><strong>34:<\/strong> Explain why more stars are circumpolar for observers at higher latitudes.<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326280419\">\n<div class=\"problem\" id=\"fs-id1170326280422\">\n<p id=\"fs-id1170326245680\"><strong>35:<\/strong> What is the altitude of the north celestial pole in the sky from your latitude? If you do not know your latitude, look it up. If you are in the Southern Hemisphere, answer this question for the south celestial pole, since the north celestial pole is not visible from your location.<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326331946\">\n<div class=\"problem\" id=\"fs-id1170326320484\">\n<p id=\"fs-id1170326320486\"><strong>36:<\/strong> If you were to drive to some city south of your current location, how would the altitude of the celestial pole in the sky change?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326202886\">\n<div class=\"problem\" id=\"fs-id1170326202889\">\n<p id=\"fs-id1170326453766\"><strong>37:<\/strong> Hipparchus could have warned us that the dates associated with each of the natal astrology sun signs would eventually be wrong. Explain why.<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326471567\">\n<div class=\"problem\" id=\"fs-id1170326471569\">\n<p id=\"fs-id1170326243620\"><strong>38:<\/strong> Explain three lines of evidence that argue against the validity of astrology.<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326178350\">\n<div class=\"problem\" id=\"fs-id1170326178352\">\n<p id=\"fs-id1170326287998\"><strong>39:<\/strong> What did Galileo discover about the planet Jupiter that cast doubt on exclusive geocentrism?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326285030\">\n<div class=\"problem\" id=\"fs-id1170326285033\">\n<p id=\"fs-id1170326452938\"><strong>40:<\/strong> What did Galileo discover about Venus that cast doubt on geocentrism?<\/p>\n<\/div>\n<\/div>\n<\/section>\n<section id=\"fs-id1170326453099\" class=\"figuring-for-yourself\">\n<h1>Figuring for Yourself<\/h1>\n<div class=\"exercise\" id=\"fs-id1170326285909\">\n<div class=\"problem\" id=\"fs-id1170326204660\">\n<p id=\"fs-id1170326204662\"><strong>41:<\/strong> Suppose Eratosthenes had found that, in Alexandria, at noon on the first day of summer, the line to the Sun makes an angle 30\u00b0 with the vertical. What, then, would he have found for Earth\u2019s circumference?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326450365\">\n<div class=\"problem\" id=\"fs-id1170326450367\">\n<p id=\"fs-id1170326451644\"><strong>42:<\/strong> Suppose Eratosthenes\u2019 results for Earth\u2019s circumference were quite accurate. If the diameter of Earth is 12,740 km, what is the length of his stadium in kilometers?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326449166\">\n<div class=\"problem\" id=\"fs-id1170326335213\">\n<p id=\"fs-id1170326335215\"><strong>43:<\/strong> Suppose you are on a strange planet and observe, at night, that the stars do not rise and set, but circle parallel to the horizon. Next, you walk in a constant direction for 8000 miles, and at your new location on the planet, you find that all stars rise straight up in the east and set straight down in the west, perpendicular to the horizon. How could you determine the circumference of the planet without any further observations? What is the circumference, in miles, of the planet?<\/p>\n<\/div>\n<\/div>\n<\/section>\n<div>\n<h2>Glossary<\/h2>\n<dl id=\"fs-id1170326396909\" class=\"definition\">\n<dt>accelerate<\/dt>\n<dd id=\"fs-id1170326470898\">to change velocity; to speed up, slow down, or change direction.<\/dd>\n<\/dl>\n<dl id=\"fs-id1170326450350\" class=\"definition\">\n<dt>heliocentric<\/dt>\n<dd id=\"fs-id1170326322884\">centred on the Sun<\/dd>\n<\/dl>\n<\/div>\n\n","rendered":"<section id=\"fs-id1170326170688\" class=\"group-activities\">\n<h1>Collaborative Group Activities<\/h1>\n<ol id=\"fs-id1170326314943\">\n<li>With your group, consider the question with which we began this chapter. How many ways can you think of to prove to a member of the \u201cFlat Earth Society\u201d that our planet is, indeed, round?<\/li>\n<li>Make a list of ways in which a belief in astrology (the notion that your life path or personality is controlled by the position of the Sun, Moon, and planets at the time of your birth) might be harmful to an individual or to society at large.<\/li>\n<li>Have members of the group compare their experiences with the night sky. Did you see the Milky Way? Can you identify any constellations? Make a list of reasons why you think so many fewer people know the night sky today than at the time of the ancient Greeks. Discuss reasons for why a person, today, may want to be acquainted with the night sky.<\/li>\n<li>Constellations commemorate great heroes, dangers, or events in the legends of the people who name them. Suppose we had to start from scratch today, naming the patterns of stars in the sky. Whom or what would you choose to commemorate by naming a constellation after it, him, or her and why (begin with people from history; then if you have time, include living people as well)? Can the members of your group agree on any choices?<\/li>\n<li>Although astronomical mythology no longer holds a powerful sway over the modern imagination, we still find proof of the power of astronomical images in the number of products in the marketplace that have astronomical names. How many can your group come up with? (Think of things like Milky Way candy bars, Eclipse and Orbit gum, or Comet cleanser.)<\/li>\n<\/ol>\n<\/section>\n<section id=\"fs-id1170326275940\" class=\"review-questions\">\n<h1>Review Questions<\/h1>\n<div class=\"exercise\" id=\"fs-id1170326051253\">\n<div class=\"problem\" id=\"fs-id1170326160367\">\n<p id=\"fs-id1170326098916\"><strong>1:<\/strong> From where on Earth could you observe all of the stars during the course of a year? What fraction of the sky can be seen from the North Pole?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326053402\">\n<div class=\"problem\" id=\"fs-id1170326189756\">\n<p id=\"fs-id1170326025588\"><strong>2:<\/strong> Give four ways to demonstrate that Earth is spherical.<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326226275\">\n<div class=\"problem\" id=\"fs-id1170326126213\">\n<p id=\"fs-id1170326275618\"><strong>3:<\/strong> Explain, according to both geocentric and heliocentric cosmologies, why we see retrograde motion of the planets.<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326454048\">\n<div class=\"problem\" id=\"fs-id1170326052958\">\n<p id=\"fs-id1170326130783\"><strong>4:<\/strong> In what ways did the work of Copernicus and Galileo differ from the views of the ancient Greeks and of their contemporaries?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326320724\">\n<div class=\"problem\" id=\"fs-id1170326204000\">\n<p id=\"fs-id1170326190029\"><strong>5:<\/strong> What were four of Galileo\u2019s discoveries that were important to astronomy?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326189344\">\n<div class=\"problem\" id=\"fs-id1170326244106\">\n<p id=\"fs-id1170326024454\"><strong>6:<\/strong> Explain the origin of the magnitude designation for determining the brightness of stars. Why does it seem to go backward, with smaller numbers indicating brighter stars?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326314036\">\n<div class=\"problem\" id=\"fs-id1170326066555\">\n<p id=\"fs-id1170326119333\"><strong>7:<\/strong> Ursa Minor contains the pole star, Polaris, and the asterism known as the Little Dipper. From most locations in the Northern Hemisphere, all of the stars in Ursa Minor are circumpolar. Does that mean these stars are also above the horizon during the day? Explain.<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326453293\">\n<div class=\"problem\" id=\"fs-id1170326141173\">\n<p id=\"fs-id1170326119377\"><strong>8:<\/strong> How many degrees does the Sun move per day relative to the fixed stars? How many days does it take for the Sun to return to its original location relative to the fixed stars?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326449708\">\n<div class=\"problem\" id=\"fs-id1170326118814\">\n<p id=\"fs-id1170326129646\"><strong>9:<\/strong> How many degrees does the Moon move per day relative to the fixed stars? How many days does it take for the Moon to return to its original location relative to the fixed stars?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326115529\">\n<div class=\"problem\" id=\"fs-id1170326290808\">\n<p id=\"fs-id1170326452150\"><strong>10:<\/strong> Explain how the zodiacal constellations are different from the other constellations.<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326334966\">\n<div class=\"problem\" id=\"fs-id1170326328600\">\n<p id=\"fs-id1170326276061\"><strong>11:<\/strong> The Sun was once thought to be a planet. Explain why.<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326323065\">\n<div class=\"problem\" id=\"fs-id1170326166043\">\n<p id=\"fs-id1170326074811\"><strong>12:<\/strong> Is the ecliptic the same thing as the celestial equator? Explain.<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326276910\">\n<div class=\"problem\" id=\"fs-id1170326243164\">\n<p id=\"fs-id1170326280677\"><strong>13:<\/strong> What is an asterism? Can you name an example?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326325438\">\n<div class=\"problem\" id=\"fs-id1170326205374\">\n<p id=\"fs-id1170326202153\"><strong>14:<\/strong> Why did Pythagoras believe that Earth should be spherical?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326279489\">\n<div class=\"problem\" id=\"fs-id1170326452840\">\n<p id=\"fs-id1170326166820\"><strong>15:<\/strong> How did Aristotle deduce that the Sun is farther away from Earth than the Moon?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326285675\">\n<div class=\"problem\" id=\"fs-id1170326335325\">\n<p id=\"fs-id1170326167111\"><strong>16:<\/strong> What are two ways in which Aristotle deduced that Earth is spherical?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326204421\">\n<div class=\"problem\" id=\"fs-id1170326021529\">\n<p id=\"fs-id1170326023932\"><strong>17:<\/strong> How did Hipparchus discover the wobble of Earth\u2019s axis, known as <em>precession<\/em>?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326125372\">\n<div class=\"problem\" id=\"fs-id1170326243233\">\n<p id=\"fs-id1170326272782\"><strong>18:<\/strong> Why did Ptolemy have to introduce multiple circles of motion for the planets instead of a single, simple circle to represent the planet\u2019s motion around the Sun?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326219829\">\n<div class=\"problem\" id=\"fs-id1170326243302\">\n<p id=\"fs-id1170326272140\"><strong>19:<\/strong> Why did Copernicus want to develop a completely new system for predicting planetary positions? Provide two reasons.<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326021484\">\n<div class=\"problem\" id=\"fs-id1170326133414\">\n<p id=\"fs-id1170326450680\"><strong>20:<\/strong> What two factors made it difficult, at first, for astronomers to choose between the Copernican heliocentric model and the Ptolemaic geocentric model?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326320087\">\n<div class=\"problem\" id=\"fs-id1170326186336\">\n<p id=\"fs-id1170326336432\"><strong>21:<\/strong> What phases would Venus show if the geocentric model were correct?<\/p>\n<\/div>\n<\/div>\n<\/section>\n<section id=\"fs-id1170326052774\" class=\"thought-questions\">\n<h1>Thought Questions<\/h1>\n<div class=\"exercise\" id=\"fs-id1170326118837\">\n<div class=\"problem\" id=\"fs-id1170326242732\">\n<p id=\"fs-id1170326217029\"><strong>22:<\/strong> Describe a practical way to determine in which constellation the Sun is found at any time of the year.<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326203149\">\n<div class=\"problem\" id=\"fs-id1170326203972\">\n<p id=\"fs-id1170326025880\"><strong>23:<\/strong> What is a constellation as astronomers define it today? What does it mean when an astronomer says, \u201cI saw a comet in Orion last night\u201d?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326243085\">\n<div class=\"problem\" id=\"fs-id1170326054296\">\n<p id=\"fs-id1170326169753\"><strong>24:<\/strong> Draw a picture that explains why Venus goes through phases the way the Moon does, according to the heliocentric cosmology. Does Jupiter also go through phases as seen from Earth? Why?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326067695\">\n<div class=\"problem\" id=\"fs-id1170326451668\">\n<p id=\"fs-id1170326121988\"><strong>25:<\/strong> Show with a simple diagram how the lower parts of a ship disappear first as it sails away from you on a spherical Earth. Use the same diagram to show why lookouts on old sailing ships could see farther from the masthead than from the deck. Would there be any advantage to posting lookouts on the mast if Earth were flat? (Note that these nautical arguments for a spherical Earth were quite familiar to Columbus and other mariners of his time.)<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326487969\">\n<div class=\"problem\" id=\"fs-id1170326216661\">\n<p id=\"fs-id1170326243256\"><strong>26:<\/strong> Parallaxes of stars were not observed by ancient astronomers. How can this fact be reconciled with the heliocentric hypothesis?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326450800\">\n<div class=\"problem\" id=\"fs-id1170326021605\">\n<p id=\"fs-id1170326177973\"><strong>27:<\/strong> Why do you think so many people still believe in astrology and spend money on it? What psychological needs does such a belief system satisfy?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326272237\">\n<div class=\"problem\" id=\"fs-id1170326119045\">\n<p id=\"fs-id1170326453270\"><strong>28:<\/strong> Consider three cosmological perspectives\u2014the geocentric perspective, the heliocentric perspective, and the modern perspective\u2014in which the Sun is a minor star on the outskirts of one galaxy among billions. Discuss some of the cultural and philosophical implications of each point of view.<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326324939\">\n<div class=\"problem\" id=\"fs-id1170326281687\">\n<p id=\"fs-id1170326074576\"><strong>29:<\/strong> The north celestial pole appears at an altitude above the horizon that is equal to the observer\u2019s latitude. Identify Polaris, the North Star, which lies very close to the north celestial pole. Measure its altitude. (This can be done with a protractor. Alternatively, your fist, extended at arm\u2019s length, spans a distance approximately equal to 10\u00b0.) Compare this estimate with your latitude. (Note that this experiment cannot be performed easily in the Southern Hemisphere because Polaris itself is not visible in the south and no bright star is located near the south celestial pole.)<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326205241\">\n<div class=\"problem\" id=\"fs-id1170326320170\">\n<p id=\"fs-id1170326334750\"><strong>30:<\/strong> What were two arguments or lines of evidence in support of the geocentric model?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326201261\">\n<div class=\"problem\" id=\"fs-id1170326024540\">\n<p id=\"fs-id1170326150186\"><strong>31:<\/strong> Although the Copernican system was largely correct to place the Sun at the center of all planetary motion, the model still gave inaccurate predictions for planetary positions. Explain the flaw in the Copernican model that hindered its accuracy.<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326077736\">\n<div class=\"problem\" id=\"fs-id1170326055981\">\n<p id=\"fs-id1170326222748\"><strong>32:<\/strong> During a retrograde loop of Mars, would you expect Mars to be brighter than usual in the sky, about average in brightness, or fainter than usual in the sky? Explain.<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326314189\">\n<div class=\"problem\" id=\"fs-id1170326339148\">\n<p id=\"fs-id1170326204570\"><strong>33:<\/strong> The Great Pyramid of Giza was constructed nearly 5000 years ago. Within the pyramid, archaeologists discovered a shaft leading from the central chamber out of the pyramid, oriented for favorable viewing of the bright star Thuban at that time. Thinking about Earth\u2019s precession, explain why Thuban might have been an important star to the ancient Egyptians.<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326098990\">\n<div class=\"problem\" id=\"fs-id1170326098992\">\n<p id=\"fs-id1170326334665\"><strong>34:<\/strong> Explain why more stars are circumpolar for observers at higher latitudes.<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326280419\">\n<div class=\"problem\" id=\"fs-id1170326280422\">\n<p id=\"fs-id1170326245680\"><strong>35:<\/strong> What is the altitude of the north celestial pole in the sky from your latitude? If you do not know your latitude, look it up. If you are in the Southern Hemisphere, answer this question for the south celestial pole, since the north celestial pole is not visible from your location.<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326331946\">\n<div class=\"problem\" id=\"fs-id1170326320484\">\n<p id=\"fs-id1170326320486\"><strong>36:<\/strong> If you were to drive to some city south of your current location, how would the altitude of the celestial pole in the sky change?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326202886\">\n<div class=\"problem\" id=\"fs-id1170326202889\">\n<p id=\"fs-id1170326453766\"><strong>37:<\/strong> Hipparchus could have warned us that the dates associated with each of the natal astrology sun signs would eventually be wrong. Explain why.<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326471567\">\n<div class=\"problem\" id=\"fs-id1170326471569\">\n<p id=\"fs-id1170326243620\"><strong>38:<\/strong> Explain three lines of evidence that argue against the validity of astrology.<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326178350\">\n<div class=\"problem\" id=\"fs-id1170326178352\">\n<p id=\"fs-id1170326287998\"><strong>39:<\/strong> What did Galileo discover about the planet Jupiter that cast doubt on exclusive geocentrism?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326285030\">\n<div class=\"problem\" id=\"fs-id1170326285033\">\n<p id=\"fs-id1170326452938\"><strong>40:<\/strong> What did Galileo discover about Venus that cast doubt on geocentrism?<\/p>\n<\/div>\n<\/div>\n<\/section>\n<section id=\"fs-id1170326453099\" class=\"figuring-for-yourself\">\n<h1>Figuring for Yourself<\/h1>\n<div class=\"exercise\" id=\"fs-id1170326285909\">\n<div class=\"problem\" id=\"fs-id1170326204660\">\n<p id=\"fs-id1170326204662\"><strong>41:<\/strong> Suppose Eratosthenes had found that, in Alexandria, at noon on the first day of summer, the line to the Sun makes an angle 30\u00b0 with the vertical. What, then, would he have found for Earth\u2019s circumference?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326450365\">\n<div class=\"problem\" id=\"fs-id1170326450367\">\n<p id=\"fs-id1170326451644\"><strong>42:<\/strong> Suppose Eratosthenes\u2019 results for Earth\u2019s circumference were quite accurate. If the diameter of Earth is 12,740 km, what is the length of his stadium in kilometers?<\/p>\n<\/div>\n<\/div>\n<div class=\"exercise\" id=\"fs-id1170326449166\">\n<div class=\"problem\" id=\"fs-id1170326335213\">\n<p id=\"fs-id1170326335215\"><strong>43:<\/strong> Suppose you are on a strange planet and observe, at night, that the stars do not rise and set, but circle parallel to the horizon. Next, you walk in a constant direction for 8000 miles, and at your new location on the planet, you find that all stars rise straight up in the east and set straight down in the west, perpendicular to the horizon. How could you determine the circumference of the planet without any further observations? What is the circumference, in miles, of the planet?<\/p>\n<\/div>\n<\/div>\n<\/section>\n<div>\n<h2>Glossary<\/h2>\n<dl id=\"fs-id1170326396909\" class=\"definition\">\n<dt>accelerate<\/dt>\n<dd id=\"fs-id1170326470898\">to change velocity; to speed up, slow down, or change direction.<\/dd>\n<\/dl>\n<dl id=\"fs-id1170326450350\" class=\"definition\">\n<dt>heliocentric<\/dt>\n<dd id=\"fs-id1170326322884\">centred on the Sun<\/dd>\n<\/dl>\n<\/div>\n","protected":false},"author":61,"menu_order":1,"template":"","meta":{"pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-98","chapter","type-chapter","status-publish","hentry"],"part":62,"_links":{"self":[{"href":"https:\/\/pressbooks.bccampus.ca\/astronomy1105dl\/wp-json\/pressbooks\/v2\/chapters\/98","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pressbooks.bccampus.ca\/astronomy1105dl\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/pressbooks.bccampus.ca\/astronomy1105dl\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/astronomy1105dl\/wp-json\/wp\/v2\/users\/61"}],"version-history":[{"count":1,"href":"https:\/\/pressbooks.bccampus.ca\/astronomy1105dl\/wp-json\/pressbooks\/v2\/chapters\/98\/revisions"}],"predecessor-version":[{"id":99,"href":"https:\/\/pressbooks.bccampus.ca\/astronomy1105dl\/wp-json\/pressbooks\/v2\/chapters\/98\/revisions\/99"}],"part":[{"href":"https:\/\/pressbooks.bccampus.ca\/astronomy1105dl\/wp-json\/pressbooks\/v2\/parts\/62"}],"metadata":[{"href":"https:\/\/pressbooks.bccampus.ca\/astronomy1105dl\/wp-json\/pressbooks\/v2\/chapters\/98\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/pressbooks.bccampus.ca\/astronomy1105dl\/wp-json\/wp\/v2\/media?parent=98"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/astronomy1105dl\/wp-json\/pressbooks\/v2\/chapter-type?post=98"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/astronomy1105dl\/wp-json\/wp\/v2\/contributor?post=98"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/astronomy1105dl\/wp-json\/wp\/v2\/license?post=98"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}