The Cosmic Perspective, 7th Edition, Testbank | 2022 latest update

The Cosmic Perspective, 7th Edition, Testbank | 2022 latest update 1 Copyright © 2014 Pearson Education, Inc. The Cosmic Perspective, 7e (Bennett et al.) Chapter 1 A Modern View of the Universe 1.1 Multiple-Choice Questions 1) What is the meaning of the word cosmos? A) the origin of Earth and life upon it B) the light from a distant astronomical object C) the Milky Way D) the sum total of all matter and energy, that is, everything within and between all galaxies E) the dark sky Answer: D 2) Which of the following has your "address" in the correct order? A) you, Earth, solar system, Local Group, Local Supercluster, Milky Way B) you, Earth, solar system, Milky Way, Local Supercluster, Local Group C) you, Earth, solar system, Local Group, Milky Way, Local Supercluster D) you, Earth, Local Group, Local Supercluster, solar system, Milky Way E) you, Earth, solar system, Milky Way, Local Group, Local Supercluster Answer: E 3) About where is our solar system located within the Milky Way Galaxy? A) at the center of the galaxy B) about 10 percent of the way from the center of the galaxy to the outskirts of the galactic disk C) about two-thirds of the way from the center of the galaxy to the outskirts of the galactic disk D) near the far outskirts of the galactic disk E) in the halo of the galaxy above the galactic disk Answer: C 4) Roughly how many stars are in the Milky Way Galaxy? A) 1 billion B) 100 billion C) 10 billion D) 100 million E) 100 trillion Answer: B 5) Modern telescopes are capable of seeing bright galaxies up to about A) 1 million light-years away. B) 10 million light-years away. C) 1 billion light-years away. D) 10 billion light-years away. E) 1 trillion light-years away. Answer: D 2 Copyright © 2014 Pearson Education, Inc. 6) Suppose we imagine the Sun to be about the size of a grapefruit. How big an area would the orbits of the eight planets of the solar system cover? A) the size of a typical dorm room B) the size of a typical campus building C) the size of a typical campus D) the size of a small city E) the size of a western state (e.g., Colorado) Answer: C 7) What do we mean when we say that the universe is expanding? A) Average distances are increasing between star systems within galaxies. B) Everything in the universe is gradually growing in size. C) Average distances are increasing between galaxies. D) The statement is not meant to be literal; rather, it means that our knowledge of the universe is growing. E) Individual galaxies are gradually growing in size. Answer: C 8) The age of the universe is A) between 10 million and 16 million years. B) between 100 million and 160 million years. C) between 1 billion and 1.6 billion years. D) between 10 billion and 16 billion years. E) between 100 billion and 160 billion years. Answer: D 9) How are galaxies important to our existence? A) Without galaxies, there could not have been a Big Bang. B) Without galaxies, the universe could not be expanding. C) Galaxies prevent planets from leaving their orbits around stars; e.g., our galaxy prevents Earth from leaving its orbit of the Sun. D) Galaxies recycle heavy elements produced in stars into future generations of stars. E) Galaxies provide the gravity that prevents us from falling off Earth. Answer: D 10) Earth is made mostly of metals and rocks. Where did this material come from? A) It was produced in the Big Bang. B) It was created by chemical reactions in interstellar space. C) It was produced by nuclear fusion in stars. D) It was made by our Sun. E) It was made by nuclear fission of uranium and other radioactive materials. Answer: C 3 Copyright © 2014 Pearson Education, Inc. 11) What is nuclear fusion? A) an explosion caused by putting together two volatile chemicals B) the process of splitting nuclei to produce energy C) the process of turning matter into pure energy D) the process of combining lightweight nuclei to make heavier nuclei E) a process that only occurs in bombs Answer: D 12) Why did Carl Sagan say that we are star stuff? A) The composition of most stars (mostly hydrogen and helium) is about the same as the composition of our bodies. B) Cosmic rays reaching Earth from distant astronomical sources may be one source of mutations that help evolution along. C) Nearly every atom from which we are made once (before the solar system formed) was inside of a star. D) Nearly every atom from which we are made was once inside our star, the Sun. E) Sagan thought that all of us have the potential to be movie (or TV) stars like he was. Answer: C 13) Which of the following statements does not use the term light-year in an appropriate way? A) It's about 4 light-years from here to Alpha Centauri. B) It will take me light-years to complete this homework assignment. C) A light-year is about 10 trillion kilometers. D) It will take the Voyager spacecraft about 20,000 years to travel just 1 light-year. E) The Milky Way Galaxy is about 100,000 light-years in diameter. Answer: B 14) One light-hour is the distance that light travels in an hour. How far is this, in kilometers? (Recall that the speed of light is 300,000 km/s.) A) 300,000 km B) 18 million km C) 100 million km D) 1.08 billion km E) 9.46 trillion km Answer: D 15) Suppose we look at a photograph of many galaxies. Assuming that all galaxies formed at about the same time, which galaxy in the picture is the youngest? A) the one that is farthest away B) the one that is reddest in color C) the one that is bluest in color D) the one that is closest to us E) the one that appears smallest in size Answer: A 4 Copyright © 2014 Pearson Education, Inc. 16) What do we mean by the observable universe? A) the part of the universe that we can see with the naked eye B) the part of the universe that we can see through telescopes C) the part of the universe that could be observed in principle, including things that may require future technologies D) the compendium of all objects that we have observed to date E) the entire universe, since it is inconceivable that there could be parts of the universe that we cannot observe Answer: C 17) Suppose we imagine the Sun to be about the size of a grapefruit. Which of the following describes the size and distance of Earth on the same scale? A) Earth is the size of a point about 1 meter away from the Sun. B) Earth is the size of a golf ball about 1 meter away from the Sun. C) Earth is the size of a point about 15 meters away from the Sun. D) Earth is the size of a golf ball about 15 meters away from the Sun. E) Earth is the size of a marble about 25 miles away from the Sun. Answer: C 18) What is the Sun mainly made of? A) hydrogen and oxygen B) hydrogen and helium C) carbon and nitrogen D) oxygen and carbon E) nearly equal portions of all the elements Answer: B 19) Which of the following is smallest? A) size of a typical planet B) 1 light-second C) 1 AU D) size of a typical star Answer: A 20) Which of the following is largest? A) size of a typical galaxy B) size of Pluto's orbit C) distance to the nearest star (other than our Sun) D) 1 light-year Answer: A 5 Copyright © 2014 Pearson Education, Inc. 21) On the 1-to-10-billion scale, about how far is it to the nearest stars besides the Sun? A) 4 kilometers B) 400 kilometers C) 1,000 kilometers D) 4,400 kilometers E) 10,000 kilometers Answer: D 22) Suppose we imagine the Sun to be about the size of a grapefruit. How far away are the nearest stars (the three stars of Alpha Centauri)? A) the length of a football field B) 2.5 miles C) 250 miles D) 2,500 miles E) 25,000 miles Answer: D 23) If we use 1 millimeter to represent 1 light-year, how large in diameter is the Milky Way Galaxy? A) 100 millimeters B) 100 meters C) 1 kilometer D) 100 kilometers E) 1 million millimeters Answer: B 24) Which of the following best describes the Milky Way Galaxy? A) a spiral galaxy with a disk about 100,000 light-years in diameter and containing between 100 billion and 1 trillion stars B) a spiral galaxy with a disk about 1 billion kilometers in diameter and containing between 100 million and 1 billion stars C) a spiral galaxy with a disk about 100,000 light-years in diameter and containing about 100,000 stars D) a spherically shaped collection of stars including our solar system and about a dozen other solar systems, stretching about 4 light-years in diameter E) a spherically shaped collection of about 1 million stars that is about 100 light-years in diameter Answer: A 25) How long would it take to count all the stars in the Milky Way Galaxy at a rate of one star per second? A) several days B) several weeks C) several years D) several thousand years E) hundreds of thousands of years Answer: D 6 Copyright © 2014 Pearson Education, Inc. 26) How many galaxies are there in the observable universe? A) roughly (within a factor of 10) the same as the number of stars in our galaxy B) roughly a thousand times more than the number of stars in our galaxy C) about as many as the number of stars we see in the sky with our naked eyes D) about as many as the number of grains of sand on all the beaches on Earth E) an infinite number Answer: A 27) If you represented each star by a grain of sand, how much sand would it take to represent all the stars in the universe? A) all the sand in a typical playground sandlot B) all the sand on Miami Beach C) all the sand on the beaches of California D) all the sand on the beaches in the United States E) more than all the sand on all the beaches on Earth Answer: E 28) On the scale of the cosmic calendar, in which the history of the universe is compressed to 1 year, how long has human civilization (i.e., since ancient Egypt) existed? A) about half the year B) about a month C) a few hours D) a few seconds E) less than a millionth of a second Answer: D 29) On a cosmic calendar, in which the history of the universe is compressed into 1 year, when did the dinosaurs become extinct? A) in late December B) in late November C) in late October D) in late September E) in late August Answer: A 30) On a cosmic calendar, in which the history of the universe is compressed into 1 year, when did Kepler and Galileo first discover that we live on a planet in a solar system? A) 1 second ago B) 1 day ago C) 1 week ago D) December 25 E) December 30 Answer: A 7 Copyright © 2014 Pearson Education, Inc. 31) On a cosmic calendar, in which the history of the universe is compressed into one year, how long is the average human life span? A) 0.2 millisecond B) 0.2 second C) 2 seconds D) 2 minutes E) 2 hours Answer: B 32) Approximately how fast are you moving with the rotation of Earth? A) 13,000 km/hr B) 1,300 km/hr C) 130 km/hr D) 13 km/hr E) not moving at all Answer: B 33) What is an astronomical unit? A) the average speed of Earth around the Sun B) the length of time it takes Earth to revolve around the Sun C) the average distance from Earth to the Sun D) the diameter of Earth's orbit around the Sun E) any basic unit used in astronomy Answer: C 34) Which of the following statements about the ecliptic plane is not true? A) It is the plane of Earth's orbit around the Sun. B) It is the plane of the Moon's orbit around Earth. C) During a solar eclipse, the Moon lies in the ecliptic plane. D) During a lunar eclipse, the Moon lies in the ecliptic plane. E) The nodes of the Moon's orbit lie in the ecliptic plane. Answer: B 35) Patterns of stars in constellations hardly change in appearance over times of even a few thousand years. Why? A) Stars are fixed and never move. B) Stars move, but they move very slowly–only a few kilometers in a thousand years. C) Although most stars move through the sky, the brightest stars do not, and these are the ones that trace the patterns we see in the constellations. D) The stars in our sky actually move rapidly relative to us–thousands of kilometers per hour– but are so far away that it takes a long time for this motion to make a noticeable change in the patterns in the sky. E) Stars within a constellation move together as a group, which tends to hide their actual motion and prevent the pattern from changing. Answer: D 8 Copyright © 2014 Pearson Education, Inc. 36) How long does it take our solar system to complete one orbit around the Milky Way Galaxy? A) 10 thousand years B) 230 thousand years C) 1 million years D) 100 million years E) 230 million years Answer: E 37) Which of the following statements about the Milky Way Galaxy is not true? A) It contains between 100 billion and 1 trillion stars. B) Our solar system is located very close to the center of the Milky Way Galaxy. C) Our view of distant objects is obscured by gas and dust when we look into the galactic plane. D) The galaxy is about 100,000 light-years in diameter. E) One rotation of the galaxy takes about 200 million years. Answer: B 38) Which of the following correctly lists speeds from slowest to fastest? A) Earth's speed of revolution about the Sun, typical speeds of stars in the local solar neighborhood relative to us, Earth's speed of rotation on its axis, the speed of our solar system orbiting the center of the Milky Way Galaxy, the speeds of very distant galaxies relative to us B) Earth's speed of rotation on its axis, Earth's speed of revolution about the Sun, typical speeds of stars in the local solar neighborhood relative to us, the speed of our solar system orbiting the center of the Milky Way Galaxy, the speeds of very distant galaxies relative to us C) the speeds of very distant galaxies relative to us, typical speeds of stars in the local solar neighborhood relative to us, Earth's speed of rotation on its axis, Earth's speed of revolution about the Sun, the speed of our solar system orbiting the center of the Milky Way Galaxy D) the speed of our solar system orbiting the center of the Milky Way Galaxy, Earth's speed of revolution about the Sun, Earth's speed of rotation on its axis, the speeds of very distant galaxies relative to us, typical speeds of stars in the local solar neighborhood relative to us E) Earth's speed of revolution about the Sun, Earth's speed of rotation on its axis, the speed of our solar system orbiting the center of the Milky Way Galaxy, typical speeds of stars in the local solar neighborhood relative to us, the speeds of very distant galaxies relative to us Answer: B 39) Most of the mass in the Milky Way Galaxy is located A) in the halo (above/below the disk). B) within the disk. C) in the stars in the spiral arms. D) in the gas and dust. E) in the central bulge of the galaxy. Answer: A 9 Copyright © 2014 Pearson Education, Inc. 40) The distribution of the mass of the Milky Way Galaxy is determined by A) counting the number of stars. B) determining the amount of gas and dust. C) studying how stars are distributed in the Milky Way. D) studying the rotation of the galaxy. E) weighing various parts of the Milky Way. Answer: D 41) From the fact that virtually every galaxy is moving away from us and more distant galaxies are moving away from us at a faster rate than closer ones, we conclude that A) the Milky Way Galaxy is expanding. B) we are located at the center of the universe. C) the farthest galaxies will eventually be moving faster than the speed of light. D) the universe is expanding. E) the universe is shrinking. Answer: D 42) By studying distant galaxies in the 1920s, Hubble made which of the following important discoveries that led us to conclude that the universe is expanding? A) All galaxies contain billions of stars, and all galaxies have spiral shapes. B) All galaxies were born at the same time, and all will die at the same time. C) All galaxies outside the Local Group are moving away from us, and the farther away they are, the faster they're going. D) All galaxies outside the Local Group are orbiting the Local Group. E) All galaxies outside the Local Group are moving away from us, and all are moving away at nearly the same speed. Answer: C 43) Imagine that we put a raisin cake into the oven, with each raisin separated from the others by 1 cm. An hour later, we take it out and the distances between raisins are 3 cm. If you lived in one of the raisins and watched the other raisins as the cake expanded, which of the following would you conclude? A) All raisins would be moving away from you at the same speed. B) More distant raisins would be moving away from you faster. C) More distant raisins would be moving away from you more slowly. D) It depends: If you lived in a raisin near the edge of the cake, you'd see other raisins moving away from you, but they'd be coming toward you if you lived in a raisin near the center of the cake. Answer: B 10 Copyright © 2014 Pearson Education, Inc. 44) Which scientists played a major role in overturning the ancient idea of an Earth-centered universe, and about when? A) Copernicus, Kepler, and Galileo; about 400 years ago B) Aristotle and Copernicus; about 400 years ago C) Newton and Einstein; about 100 years ago D) Huygens and Newton; about 300 years ago E) Aristotle and Plato; about 2,000 years ago Answer: A 1.2 True/False Questions 1) Our solar system is located in the center of the Milky Way Galaxy. Answer: FALSE 2) The solar system contains about 100 billion stars. Answer: FALSE 3) A typical supercluster contains no more than about 10,000 stars. Answer: FALSE 4) One light-year is about 10 trillion kilometers. Answer: TRUE 5) In the grapefruit model of the solar system, it would take a few minutes to walk from the Sun to the inner edge of the Kuiper Belt (Pluto). Answer: TRUE 6) The observable universe is the same size today as it was a few billion years ago. Answer: FALSE 7) The Milky Way is moving further away from most other galaxies in the Universe. Answer: TRUE 8) No galaxies existed before the Big Bang. Answer: TRUE 9) Voyager 2 should reach the nearest stars (besides the Sun) in about 500 years. Answer: FALSE 10) Earth is always precisely 1 AU from the Sun. Answer: FALSE 11 Copyright © 2014 Pearson Education, Inc. 1.3 Short Answer Questions 1) The speed of light is 300,000 km/s. How far is a light-year? Be sure to show all work clearly on your calculations. Answer: 1 light-year = (speed of light) × (1 yr) = × × × × = 9,460,000,000,000 km 2) How big is Earth on the 1-to-10 billion scale described in Section 1.2. Answer: Scaled radius of Earth = actual radius / 1010 = 6,378 km / 1010 = 6,378 × 105 cm / 1010 = 6.378 × 108 cm / 1010 = 6.378 × 10-2 cm = 0.6 mm This is about the size of the tip of a (fine tip) ballpoint pen. 3) Briefly explain what we mean by the statement "The farther away we look in distance, the further back we look in time." Answer: It means that when we look at a distant object, we see it as it was some time in the past, rather than as it is now. This is because the light we see has taken time to travel from the object to us. 4) Starting from the Big Bang, briefly explain how our solar system came to contain the chemical elements necessary to make Earth and living organisms. Answer: The Big Bang produced hydrogen and helium. Over time, stars have converted about 2 percent of this material into heavier elements, including all the elements of which we and Earth are made. Stars expel this material through winds and explosions, and the galaxy recycles it into new generations of stars. When a new star system forms, it therefore contains the ingredients needed to make planets and living organisms. 5) Briefly explain why an expanding universe implies a beginning (called a Big Bang). Answer: The fact that the universe is expanding means the average distance between galaxies is growing, which implies that this average distance was smaller in the past. Extrapolating back in time, there must have been a time when the distance between galaxies (or their precursors) was zero, which must be the beginning of the universe. 6) Consider the following statement, and explain whether or not it is sensible: NASA hopes to build a new telescope that will allow us to see 100 million light-years into the past. Answer: Not sensible: It uses light-years as a length of time. 12 Copyright © 2014 Pearson Education, Inc. 7) Consider the following statement, and explain whether or not it is sensible: NASA hopes to build a new telescope that will allow us to see some galaxies as they appeared 8 billion years ago. Answer: Sensible: By looking to a distance of 8 billion light-years, we can see objects as they looked 8 billion years ago. 8) Consider the following statement, and explain whether or not it is sensible: The universe is between 10 and 16 billion light-years old. Answer: This statement does not make sense because it uses the term light-year as a length of time, rather than as a distance. 9) Consider the following statement, and explain whether or not it is sensible: It will take me light-years to complete this homework assignment. Answer: This statement does not make sense because it uses the term light-year as a length of time, rather than as a distance. 10) Consider the following statement, and explain whether or not it is sensible: Someday we may build spaceships capable of traveling at a speed of 1 light-second per hour. Answer: This statement is fine. A light-second is 300,000 kilometers, so it simply says that we'll someday build spaceships that can travel at a speed of 300,000 km/hr. 11) Briefly explain how the Sun generates energy. Answer: The Sun generates energy through nuclear fusion in its core, converting hydrogen into helium. This process releases energy because a small amount of the mass of the hydrogen is converted to energy. 12) Imagine that you could drive your car in space. Assume that you can drive at a constant speed of 100 kilometers per hour. Suppose you started driving from the Sun. How long would it take, in years, to reach Earth? Answer: t = = 1.5 million hours = 171 years It would take about 171 years to drive from the Sun to Earth. 13) Explain why it is so difficult to see planets around other stars. Answer: Planets are very faint compared to the stars they orbit. Moreover, they are very close to their parent star compared to the distance between stars. On the 1-to-10 billion scale, where the Sun is the size of a grapefruit and Earth is a pinhead about 15 meters way, the nearest star is several thousand kilometers away. Together, this makes it extremely difficult to distinguish the faint light of a planet from the star it orbits. (Nevertheless, massive Jupiter-like planets have been indirectly detected orbiting around nearby stars.) 13 Copyright © 2014 Pearson Education, Inc. 14) Based on the idea of "spaceship Earth," write one or two paragraphs explaining why it is not the case that we are "just sitting here." Answer: Far from just sitting still, we on Earth are moving relative to the Sun, planets, stars, and even other galaxies. The rotation of Earth causes the most noticeable changes in the sky. This motion around Earth's axis causes the Sun and stars to appear to rise and set, producing what we call a "day." The revolution of Earth about the Sun produces the monthly changes of the constellations, the seasonal weather changes due to Earth's tilt, and the parallax of some stars. The precession of Earth's axis, a very slow movement that has a period of 26,000 years, causes the movement of the North Star, and the changing position of the equinoxes and solstices. The motion of the Sun relative to the stars in the local solar neighborhood is at an extremely fast speed, although barely noticeable. Over time, this movement causes the patterns of the stars in the sky to change. The rotation of the galaxy means that the entire solar system is also orbiting the center of the Milky Way. This also produces motions of stars and clouds of gas. The expansion of the universe, the fact that the space between most galaxies is increasing with time, means that almost all galaxies outside the Local Group are moving away from us, with the more distant ones moving away faster. All of these motions, although not felt by us on Earth, are observed by watching the sky and prove that we are not "just sitting here." 15) How fast is the Moon orbiting Earth? Answer: From Appendix E, you can find that the distance from Earth to the Moon is 384.4 x 103 km and the orbital period of the Moon around Earth is 27.322 days. The orbital circumference is therefore 2 × π × 3.844 × 105 km ≈ 2.42 × 106 km, and the orbital period in hours is 27.322 × 24 ≈ 6.56 hours. Therefore, orbital speed = = ≈ 3700 km/hr 16) Consider the following statement, and explain whether or not it is sensible: Earth is always precisely 1 AU from the Sun. Answer: Not sensible: One AU is the average distance between Earth and the Sun. 17) Process of Science: Devise an experiment that would produce evidence (not necessarily proof) that Earth is round. You may use any technology you like, but you may not leave Earth (i.e., no satellite photos and no space travel). Be as creative as you like–there are many right answers. Answer: Some answers are: circumnavigate the globe; call a friend in Japan during the day here and find out that it's night there; watch the sails of ships sailing off into the distance; observe Polaris from the North Pole and watch its position change as you move towards the equator, etc. 14 Copyright © 2014 Pearson Education, Inc. 18) Process of Science: Think of some ways in which you can demonstrate the following by simply looking at the sky: a) the Sun and stars lie beyond the Earth's atmosphere b) the stars are further away than the Moon Answer: a) The Sun and stars disappear behind clouds. That tells us that clouds, in our atmosphere, lie between us and the stars. b) As the Moon moves across the sky, it blocks out ("occults") stars. This tells us that the Moon lies between us and the stars. 19) Process of Science: Think about some ways in which we might figure out how old things are that last for much longer than a human lifetime. What about for things that last longer than humans have existed? Answer: For relatively recent events, we can look at the human historical record as written in books, painted on rocks, or just passed on orally from generation to generation. There are several such examples that pertain to astronomical phenomena such as comets and supernovae. In the case of events that happened before humans existed, we have to look at evidence in the Earth's geological record. An example is the iridium layer that suggests a massive explosion the spread ejecta around the globe. We can also use radioisotope dating where we use the known timescale for the decay of a radioactive element to measure the age of an object such as a meteorite. 1.4 Mastering Astronomy Reading Quiz 1) Which of the following is not a general difference between a planet and a star? A) Planets are smaller than stars. B) Planets are dimmer than stars. C) All planets are made of rock and all stars are made of gas. D) Planets orbit stars, while stars orbit the center of the galaxy. Answer: C 2) Our solar system consists of A) the Sun and all the objects that orbit it. B) the Sun and the planets, and nothing else. C) a few hundred billion stars, bound together by gravity. D) the Sun and several nearby stars, as well as the planets and other objects that orbit these stars. Answer: A 3) A typical galaxy is a A) collection of a few hundred million to a trillion or more stars, bound together by gravity. B) large, glowing ball of gas powered by nuclear energy. C) nearby object orbiting a planet. D) relatively small, icy object orbiting a star. Answer: A 15 Copyright © 2014 Pearson Education, Inc. 4) Which of the following best describes what we mean by the universe? A) the sum total of all matter and energy B) a vast collection of stars that number as many as the grains of sand on all the beaches on Earth C) all the galaxies in all the superclusters D) The universe is another name for our Milky Way Galaxy. Answer: A 5) What do astronomers mean by the Big Bang? A) the event that marked the beginning of the expansion of the universe B) a gigantic explosion that blew all the galaxies in the universe to smithereens C) the explosion of a massive star at the end of its life D) the event that marked the birth of our solar system Answer: A 6) What do we mean when we say that the universe is expanding? A) Everything in the universe is gradually growing in size. B) Within galaxies, average distances between star systems are increasing with time. C) The statement is not meant to be literal; rather, it means that our knowledge of the universe is growing. D) Average distances between galaxies are increasing with time. Answer: D 7) Based on observations of the universal expansion, the age of the universe is about A) 14,000 years. B) 14 million years. C) 14 billion years. D) 14 trillion years. Answer: C 8) A television advertisement claiming that a product is light-years ahead of its time does not make sense because A) it doesn't specify the number of light-years. B) it uses "light-years" to talk about time, but a light-year is a unit of distance. C) a light-year is an astronomically large unit, so a product could not possibly be so advanced. D) light-years can only be used to talk about light. Answer: B 9) The term observable universe refers to A) that portion of the universe that we have so far photographed through telescopes. B) the portion of the universe that can be seen by the naked eye. C) the portion of the universe that is not hidden from view by, for example, being below the horizon. D) that portion of the universe that we can see in principle, given the current age of the universe. Answer: D 16 Copyright © 2014 Pearson Education, Inc. 10) On a scale in which the distance from Earth to the Sun is about 15 meters, the distance from Earth to the Moon is A) small enough to fit within your hand. B) about 1 meter. C) about 5 meters. D) about 30 meters. Answer: A 11) On a scale where the Sun is about the size of a grapefruit and the Earth is about 15 meters away, how far away are the nearest stars besides the Sun? A) 100 meters B) about the distance across 50 football fields C) about the distance across the state of Delaware D) about the distance across the United States Answer: D 12) The number of stars in the Milky Way Galaxy is approximately A) a few hundred. B) a few hundred thousand. C) a few hundred billion. D) a few hundred million. Answer: C 13) An astronomical unit (AU) is A) any very large unit, such as a light-year. B) the average distance between Earth and the Sun. C) the current distance between Earth and the Sun. D) the average distance between any planet and the Sun. Answer: B 14) What is the ecliptic plane? A) the plane of Earth's orbit around the Sun B) the plane of Earth's equator C) the plane of the Sun's equator D) the plane of the Milky Way Galaxy Answer: A 15) How long does it take the Earth to complete one orbit around the Sun? A) one year B) one day C) one month D) one week E) The time it takes Earth to orbit the Sun changes significantly from one orbit to the next. Answer: A 17 Copyright © 2014 Pearson Education, Inc. 1.5 Mastering Astronomy Concept Quiz 1) Which of the following has your "cosmic address" in the correct order? A) You, Earth, solar system, Local Group, Local Supercluster, Milky Way Galaxy, universe B) You, Earth, solar system, Milky Way Galaxy, Local Group, Local Supercluster, universe C) You, Earth, Local Group, Local Supercluster, solar system, Milky Way Galaxy, universe D) You, Earth, solar system, Local Group, Milky Way Galaxy, Local Supercluster, universe E) You, Earth, Milky Way Galaxy, solar system, Local Group, Local Supercluster, universe Answer: B 2) Using the ideas discussed in your textbook, in what sense are we "star stuff"? A) The overall chemical composition of our bodies is about the same as that of stars. B) Movie stars and other people are all made of the same stuff, so we all have the potential to be famous. C) Nearly every atom from which we are made was once inside of a star. D) We could not survive without light from our star, the Sun. Answer: C 3) How are galaxies important to our existence? A) Without galaxies, there could not have been a Big Bang. B) Without galaxies, the universe could not be expanding. C) Deep in their centers, galaxies created the elements from which we are made. D) Galaxies recycle material from one generation of stars to the next, and without this recycling we could not exist. Answer: D 4) When we look at an object that is 1,000 light-years away we see it A) as it was 1,000 years ago. B) as it was 1,000 light-years ago. C) as it is right now, but it appears 1,000 times dimmer. D) looking just the same as our ancestors would have seen it 1,000 years ago. Answer: A 5) Suppose we look at two distant galaxies: Galaxy 1 is twice as far away as Galaxy 2. In this case, A) Galaxy 1 must be twice as big as Galaxy 2. B) we are seeing Galaxy 1 as it looked at an earlier time in the history of the universe than Galaxy 2. C) we are seeing Galaxy 1 as it looked at a later time in the history of the universe than Galaxy 2. D) Galaxy 2 must be twice as old as Galaxy 1. Answer: B 18 Copyright © 2014 Pearson Education, Inc. 6) Suppose we make a scale model of our solar system, with the Sun the size of a grapefruit. Which of the following best describes what the planets would look like? A) The planets are all much smaller than the Sun. Four planets are within about 20 meters of the Sun, while the rest planets are spread much farther apart. B) The planets are all much smaller than the Sun and are spread out evenly over a distance about the length of a large classroom. C) The planets are all much smaller than the Sun. Four planets are located within a few centimeters of the Sun, and four planets are located at distances ranging up to about a meter. D) The planets range in size from about the size of a marble to the size of a baseball. They are spread out over a region about the size of a football field. Answer: A 7) If you could count stars at a rate of about one per second, how long would it take to count all the stars in the Milky Way Galaxy? A) several days B) several weeks C) several years D) several thousand years Answer: D 8) The total number of stars in the observable universe is about A) 100 billion. B) the same as the number of grains of sand in a school sandbox. C) the same as the number of grains of sand on all the beaches on Earth. D) the same as the number of atoms that make up the Earth. Answer: C 9) Where is our solar system located within the Milky Way Galaxy? A) very near the center of the galaxy B) at the far edge of the galaxy's visible disk C) roughly halfway between the center and the edge of the visible disk of the galaxy D) in the halo of the galaxy Answer: C 10) If we imagine the history of the universe compressed into one year, dinosaurs became extinct A) about 6 months ago. B) about 3 weeks ago. C) yesterday morning. D) about an hour ago. Answer: C 11) Relative to the age of the universe, how old is our solar system? A) It is about 1% as old as the universe. B) It is between about 5% and 10% as old as the universe. C) It is about one-third the age of the universe. D) It is nearly the same age as the universe. Answer: C 19 Copyright © 2014 Pearson Education, Inc. 12) How do the speeds at which we are moving with Earth's rotation and orbit compare to the speeds of more familiar objects? A) Earth's rotation carries most people around the axis faster than a commercial jet travels, and Earth's orbit carries us around the Sun faster than the Space Shuttle orbits Earth. B) Earth's rotation carries most people around the axis at about the speed of a commercial jet, and Earth's orbit carries us around the Sun at about the speed of a military jet. C) Earth's rotation carries most people around the axis at about the speed of a car on the freeway, and Earth's orbit carries us around the Sun at about the speed of a commercial jet. D) Earth's rotation carries most people around the axis at about the speed at which the Space Shuttle orbits Earth, and Earth's orbit carries us around the Sun at nearly the speed of light. Answer: A 13) Why do the patterns of the stars in our sky look the same from year to year? A) because the stars in the constellations are so far away B) because the stars in the constellations are not moving C) because the stars in the constellations all move at the same speeds and in the same directions, so they don't change their relative positions D) because the stars in the constellations move so slowly—typically about the speed of a snail— that their motions are not noticeable Answer: A 14) Astronomers infer that the universe is expanding because distant galaxies all appear to A) be growing in size. B) be moving away from us, with more distant ones moving faster. C) be made mostly of dark matter. D) rotate rapidly. Answer: B 15) Which statement about motion in the universe is not true? A) The mysterious dark matter is the fastest-moving material in the universe. B) Some stars in the Milky Way Galaxy are moving toward us and others are moving away from us. C) Except for a few nearby galaxies, all other galaxies are moving away from us. D) Your speed of rotation around Earth's axis is faster if you live near the equator than if you live near the North Pole. Answer: A 16) When did humans learn that the Earth is not the center of the universe? A) within the past 500 years B) about 2,500 years ago C) about 1,000 years ago D) We haven't; there is still considerable scientific debate about whether Earth is the center of the universe. Answer: A 1 Copyright © 2014 Pearson Education, Inc. The Cosmic Perspective, 7e (Bennett et al.) Chapter 2 Discovering the Universe for Yourself 2.1 Multiple-Choice Questions 1) How many stars can you see with your naked eye on a clear, moonless night from a dark location? A) fewer than a thousand B) a few thousand C) about ten thousand D) about a hundred thousand E) more than you could count in your lifetime Answer: B 2) Which of the following best describes the modern definition of a constellation? A) a region of the celestial sphere B) a pattern of bright stars in the sky C) a Greek mythological figure D) a collection of stars that are near one another in space E) a group of stars that all lie at about the same distance from Earth Answer: A 3) Which of the following statements about the celestial sphere is not true? A) When we look in the sky, the stars all appear to be located on the celestial sphere. B) Earth is placed at the center of the celestial sphere. C) The celestial sphere does not exist physically. D) The "celestial sphere" is just another name for our universe. E) From any location on Earth, we can see only half the celestial sphere at any one time. Answer: D 4) Which of the following statements about the celestial equator is true at all latitudes? A) It lies along the band of light we call the Milky Way. B) It represents an extension of Earth's equator onto the celestial sphere. C) It cuts the dome of your sky exactly in half. D) It extends from your horizon due east, through your zenith, to your horizon due west. E) It extends from your horizon due north, through your zenith, to your horizon due south. Answer: B 5) What is the ecliptic? A) when the Moon passes in front of the Sun B) the Moon's apparent path along the celestial sphere C) the constellations commonly used in astrology to predict the future D) the Sun's daily path across the sky E) the Sun's apparent path along the celestial sphere Answer: E 2 Copyright © 2014 Pearson Education, Inc. 6) When we look into the band of light in our sky that we call the Milky Way, can we see distant galaxies? Why or why not? A) Yes, they appear as small, fuzzy patches on the other side of our galaxy. B) Yes, there are many other galaxies that we see inside the Milky Way. C) No, because the stars, gas, and dust of the Milky Way block us from seeing them. D) No, because there are only galaxies above and below the plane of the Milky Way. E) No, we cannot see any other galaxies from Earth. Answer: C 7) Which of the following correctly describes the meridian in your sky? A) a half-circle extending from your horizon due east, through your zenith, to your horizon due west B) a half-circle extending from your horizon due north, through your zenith, to your horizon due south C) a half-circle extending from your horizon due east, through the north celestial pole, to your horizon due west D) the point directly over your head E) the boundary between the portion of the celestial sphere you can see at any moment and the portion that you cannot see Answer: B 8) If it is midnight in New York, it is A) daytime in Sydney, Australia. B) midnight in Sydney, Australia. C) midnight in Los Angeles. D) midday in Rio de Janeiro, Brazil. E) midnight everywhere. Answer: A 9) How many arcseconds are in 1°? A) 60 B) 360 C) 3,600 D) 100 E) 10,000 Answer: C 10) Which of the following statements does not use the term angular size or angular distance correctly? A) The angular size of the Moon is about 1/2 degree. B) The angular distance between those two houses in the distance is 30°. C) The angular distance between those two bright stars in the sky is about 2 meters. D) The angular size of the Sun is about the same as that of the Moon. E) You can use your outstretched hand to estimate angular sizes and angular distances. Answer: C 3 Copyright © 2014 Pearson Education, Inc. 11) What is a circumpolar star? A) a star that is close to the north celestial pole B) a star that is close to the south celestial pole C) a star that always remains above your horizon D) a star that makes a daily circle around the celestial sphere E) a star that is visible from the Arctic or Antarctic circles Answer: C 12) Which of the following statements about circumpolar stars is true at all latitudes? A) They are the stars close to the north celestial pole. B) They always remain above your horizon. C) They make relatively small circles, traveling clockwise around the north celestial pole. D) Like all other stars, they rise in the east and set in the west. E) You cannot see them from the Southern Hemisphere. Answer: B 13) We describe a position on Earth's surface by stating its A) altitude and azimuth. B) altitude and direction. C) latitude and direction. D) latitude and longitude. E) meridian and longitude. Answer: D 14) What makes the North Star, Polaris, special? A) It is the brightest star in the sky. B) It is the star straight overhead. C) It appears very near the north celestial pole. D) It is the star directly on your northern horizon. E) It can be used to determine your longitude on Earth. Answer: C 15) You are standing on Earth's equator. Which way is Polaris, the North star? A) 30 degrees up, due West B) on the northern horizon C) directly overhead D) The answer depends on whether it's winter or summer. E) The answer depends on what time of day (or night) it is. Answer: B 16) By locating the north celestial pole (NCP) in the sky, how can you determine your latitude? A) The altitude of the NCP is the same as your latitude. B) The altitude of the NCP is your angular distance from the North Pole. C) The azimuth of the NCP is the same as your latitude. D) The azimuth of the NCP is the angular distance from the North Pole. E) The altitude of the NCP is the same as your distance from the North Pole. Answer: A 4 Copyright © 2014 Pearson Education, Inc. 17) Orion is visible on winter evenings but not summer evenings because of A) interference from the full Moon. B) the tilt of Earth's axis. C) the location of Earth in its orbit. D) the precession of Earth's axis. E) baseball on television. Answer: C 18) Why do we have seasons on Earth? A) As Earth goes around the Sun and Earth's axis remains pointed toward Polaris, the Northern and Southern hemispheres alternately receive more and less direct sunlight. B) The tilt of Earth's axis constantly changes between 0 and 23 1/2°, giving us summer when Earth is tilted more and winter when it is straight up. C) Earth's distance from the Sun varies, so that it is summer when we are closer to the Sun and winter when we are farther from the Sun. D) Seasons are caused by the influence of the planet Jupiter on our orbit. Answer: A 19) Why is it summer in the Northern Hemisphere when it is winter in the Southern Hemisphere? A) The Northern Hemisphere is closer to the Sun than the Southern Hemisphere. B) The Northern Hemisphere is "on top" of Earth and therefore receives more sunlight. C) The Northern Hemisphere is tilted toward the Sun and receives more direct sunlight. D) The Northern Hemisphere is tilted away from the Sun and receives more indirect sunlight. E) It isn't: both hemispheres have the same seasons at the same time. Answer: C 20) Which of the following statements is true? A) Both the Northern and Southern hemispheres receive the same amount of sunlight on the equinoxes. B) Both the Northern and Southern hemispheres receive the same amount of sunlight on the solstices. C) The Northern Hemisphere receives the most direct sunlight on the summer solstice. D) The Southern Hemisphere receives the most direct sunlight on the summer solstice. E) Both A and C are true. Answer: E 21) Which of the following statements about constellations is false? A) There are only 88 official constellations. B) Some constellations can be seen from both the Northern and Southern hemispheres. C) Some constellations can be seen in both the winter and summer. D) It is possible to see all the constellations from Earth's equator. E) Most constellations will be unrecognizable hundreds of years from now. Answer: E 5 Copyright © 2014 Pearson Education, Inc. 22) Which of the following statements about lunar phases is true? A) The time between new Moons is two weeks. B) The time from one new Moon to the next new Moon is the same as the time from first-quarter Moon to third-quarter Moon. C) The full Moon sometimes rises around midnight. D) It is possible to have two full Moons during January, but not during February. E) It is possible to have two full Moons during November, but not during December. Answer: D 23) Which of the following is not a phase of the Moon? A) first-quarter Moon B) third-quarter Moon C) half Moon D) new Moon E) full Moon Answer: C 24) When someone on Earth observes the Moon in the first-quarter phase, someone on the Moon facing Earth observes Earth in the A) new Earth phase. B) first-quarter Earth phase. C) crescent Earth phase. D) third-quarter Earth phase. E) full Earth phase. Answer: D 25) If the Moon is setting at 6 A.M., the phase of the Moon must be A) first quarter. B) third quarter. C) full. D) new. E) waning crescent. Answer: C 26) If the Moon is setting at noon, the phase of the Moon must be A) full. B) first quarter. C) third quarter. D) waning crescent. E) waxing crescent. Answer: C 6 Copyright © 2014 Pearson Education, Inc. 27) If the Moon is rising at midnight, the phase of the Moon must be A) full. B) first quarter. C) third quarter. D) waning crescent. E) waxing crescent. Answer: C 28) At approximately what time would a full Moon be on your meridian? A) 6 A.M. B) 9 A.M. C) noon D) 6 P.M. E) midnight Answer: E 29) At approximately what time would a first quarter Moon rise? A) 6 A.M. B) 9 A.M. C) noon D) 6 P.M. E) midnight Answer: C 30) If the Moon rises around 3 A.M., its phase must be A) full. B) first quarter. C) third quarter. D) waning crescent. E) waxing crescent. Answer: D 31) In which direction does a quarter Moon rise? A) north B) south C) east D) west E) The Moon becomes a quarter Moon only after it has risen and changed phase. Answer: C 32) Why do we see essentially the same face of the Moon at all times? A) because the other face points toward us only at new Moon, when we can't see the Moon B) because the Moon does not rotate C) because the Moon's rotational and orbital periods are equal D) because the Sun illuminates only one half at a time E) because the Moon has a nearly circular orbit around Earth Answer: C 7 Copyright © 2014 Pearson Education, Inc. 33) Which of the following statements about the Moon is true? A) The Moon goes through a cycle of phases because it always has the same side facing Earth. B) If you see a full Moon from North America, someone in South America would see a new Moon. C) The Moon's distance from Earth varies during its orbit. D) The Moon is visible only at night. E) The side of the Moon facing away from Earth is in perpetual darkness. Answer: C 34) Suppose you live on the Moon. How long is a day (i.e., from sunrise to sunrise)? A) 23 hours 56 minutes B) 24 hours C) a lunar month D) a year E) about 18 years Answer: C 35) Ashen light (or earthshine) is A) sunlight reflected by Earth that illuminates the "dark" portion of the Moon. B) the sunlight that shines on the face of the Moon that we never see. C) the light from the Moon that illuminates Earth's surface at night. D) the light we see at dawn just before the Sun rises. E) the light we see at dusk just after the Sun sets. Answer: A 36) All of the following statements are true. Which one explains the reason why there is not a solar eclipse at every new Moon? A) The nodes of the Moon's orbit precess with an 18-year period. B) The orbital plane of the Moon is tilted by about 5° to the ecliptic plane. C) The Moon rotates synchronously with its revolution about Earth. D) The sidereal month is shorter than the lunar month. E) The Moon is the primary cause of tides on Earth. Answer: B 37) What effect or effects would be most significant if the Moon's orbital plane were exactly the same as the ecliptic plane? A) Solar eclipses would be much rarer. B) Solar eclipses would be much more frequent. C) Solar eclipses would last much longer. D) both A and C E) both B and C Answer: B 8 Copyright © 2014 Pearson Education, Inc. 38) What conditions are required for a solar eclipse? A) The phase of the Moon must be new, and the nodes of the Moon's orbit must be nearly aligned with Earth and the Sun. B) The phase of the Moon must be full, and the nodes of the Moon's orbit must be nearly aligned with Earth and the Sun. C) The phase of the Moon can be new or full, and the nodes of the Moon's orbit must be nearly aligned with Earth and the Sun. D) The phase of the Moon must be new, and the Moon's orbital plane must lie in the ecliptic. E) The phase of the Moon must be full, and the Moon's orbital plane must lie in the ecliptic. Answer: A 39) What conditions are required for a lunar eclipse? A) The phase of the Moon must be new, and the nodes of the Moon's orbit must be nearly aligned with Earth and the Sun. B) The phase of the Moon must be full, and the nodes of the Moon's orbit must be nearly aligned with Earth and the Sun. C) The phase of the Moon can be new or full, and the nodes of the Moon's orbit must be nearly aligned with Earth and the Sun. D) The phase of the Moon must be new, and the Moon's orbital plane must lie in the ecliptic. E) The phase of the Moon must be full, and the Moon's orbital plane must lie in the ecliptic. Answer: B 40) In addition to the conditions required for any solar eclipse, what must also be true in order for you to observe a total solar eclipse? A) Earth must lie completely within the Moon's umbra. B) Earth must lie completely within the Moon's penumbra. C) Earth must be near aphelion in its orbit of the Sun. D) The Moon's umbra must touch the area where you are located. E) The Moon's penumbra must touch the area where you are located. Answer: D 41) If part of the full Moon passes through Earth's umbra, we will see a(n) A) total lunar eclipse. B) penumbral lunar eclipse. C) partial lunar eclipse. D) partial solar eclipse. E) annular eclipse. Answer: C 42) If the Moon is relatively far from Earth, so that the umbra does not reach Earth, someone directly behind the umbra will see A) a penumbral lunar eclipse. B) a partial lunar eclipse. C) a partial solar eclipse. D) an annular eclipse. E) no eclipse. Answer: D 9 Copyright © 2014 Pearson Education, Inc. 43) When are eclipse seasons? A) in the spring and fall B) in the summer and winter C) when the nodes of the Moon's orbit are nearly aligned with the Sun D) when Earth, the Sun, and the Moon are exactly aligned for an eclipse E) during an eclipse Answer: C 44) The precession of the Moon's nodes means that A) there is a lunar eclipse every 6 months. B) there is a solar eclipse every 6 months. C) the eclipse seasons occur less than 6 months apart. D) the vernal equinox will be in Aquarius in a few hundred years. E) there are never two solar eclipses in the same year. Answer: C 45) What is the Saros cycle? A) the roughly 6-month period between eclipse seasons B) the 18-year cycle over which the pattern of eclipses repeats C) the period between total solar eclipses D) the period between a total solar eclipse and a total lunar eclipse E) the period between eclipses Answer: B 46) Ancient people who knew the Saros cycle could A) completely predict every lunar eclipse. B) completely predict every solar eclipse. C) predict what type of eclipse would occur. D) predict when they'd see the next total solar eclipse in their area. E) predict when an eclipse would happen, but not necessarily what type and where it would be visible. Answer: E 47) What happens during the apparent retrograde motion of a planet? A) The planet rises in the west and sets in the east. B) The planet appears to move westward with respect to the stars over a period of many nights. C) The planet moves backward through the sky over the course of a night. D) The planet moves backward in its orbit around the Sun. E) The planet moves through constellations that are not part of the zodiac. Answer: B 10 Copyright © 2014 Pearson Education, Inc. 48) Why are lunar eclipses more commonly seen than solar eclipses? A) Lunar eclipses occur at night and are easier to see. B) The Moon goes around the Earth faster than the Earth goes around the Sun. C) The Earth casts a bigger shadow than the Moon. D) The tilt of the Moon's axis is smaller than the Earth's. E) The Moon is much closer to the Earth than the Sun. Answer: C 49) What causes the apparent retrograde motion of the planets? A) As Earth passes another planet, its gravitational pull slows down the other planet so that it appears to be traveling backward. B) When planets are farther from the Sun, they move slower than when they are nearer the Sun; it is during this slower period that they appear to move backwards. C) The other planets never really appear to move backward; the background stars shift due to Earth's revolution around the Sun. D) As Earth passes another planet, the other planet appears to move backward with respect to the background stars, but the planet's motion does not really change. E) Apparent retrograde motion is an illusion created by turbulence in Earth's atmosphere. Answer: D 50) Which of the following never goes in retrograde motion? A) the Sun B) Venus C) Mars D) Jupiter E) Saturn Answer: A 51) Which of the following statements about parallax is not true? A) You can demonstrate parallax simply by holding up a finger and looking at it alternately from your left and right eyes. B) The existence of stellar parallax is direct proof that Earth orbits the Sun. C) Measurement of stellar parallax allows us to determine distances to nearby stars. D) The technique of stellar parallax was used by Hubble to determine that the Andromeda Galaxy (M 31) is about 2 million light-years away. E) Ancient astronomers were unable to measure parallax and used the absence of observed parallax as an argument in favor of an Earth-centered universe. Answer: D 52) Which of the following statements about stellar parallax is true? A) We observe all stars to exhibit at least a slight amount of parallax. B) Stellar parallax was first observed by ancient Greek astronomers. C) The amount of parallax we see depends on how fast a star is moving relative to us. D) It takes at least 10 years of observation to measure a star's parallax. E) The closer a star is to us, the more parallax it exhibits. Answer: E 11 Copyright © 2014 Pearson Education, Inc. 53) We can't detect stellar parallax with naked-eye observations. Which of the following would make parallax easier to observe? A) increasing the size of Earth's orbit B) speeding up Earth's rotational motion C) slowing down Earth's rotational motion D) speeding up the precession of Earth's axis E) getting away from streetlights Answer: A 54) Why were ancient peoples unable to detect stellar parallax? A) They did not look for it. B) They could not see distant stars. C) They did not have the ability to measure very small angles. D) They did not observe for long enough periods of time. E) They did detect it, but they rejected the observations. Answer: C 2.2 True/False Questions 1) In South Africa, it's usually quite warm around the time of the winter solstice and quite cool around the time of the summer solstice. Answer: TRUE 2) Columbus was the first person to discover that Earth is round. Answer: FALSE 3) You can find the tilt of Earth's axis by measuring the angle between your horizon and the North Star. Answer: FALSE 4) The Milky Way can be seen only from the Northern Hemisphere. Answer: FALSE 5) The seasons on Earth are caused by its elliptical orbit around the Sun. Answer: FALSE 6) At midnight it is sometimes possible to observe the crescent Moon on the meridian. Answer: FALSE 7) It is possible to see the third-quarter Moon near the western horizon at sunrise. Answer: FALSE 8) It is possible to see the full Moon rising just before sunrise. Answer: FALSE 9) If you lived on the Moon, you'd see full Earth when we see new Moon. Answer: TRUE 12 Copyright © 2014 Pearson Education, Inc. 10) It is possible to view the Moon in first-quarter phase the day after a total lunar eclipse. Answer: FALSE 11) The Moon and the Sun are approximately the same angular size. Answer: TRUE 12) A solar eclipse occurs only when the Moon is new. Answer: TRUE 13) A lunar eclipse occurs only when the Moon is new. Answer: FALSE 14) Lunar eclipses are more commonly seen than solar eclipses. Answer: TRUE 15) Process of Science: Because we do not see stellar parallaxes with our eyes, we conclude that the Earth is at the center of the Solar System. Answer: FALSE 2.3 Short Answer Questions Choose the letter for the real motion of space from the list below that is responsible for the apparent motion of space as seen from Earth. A. Earth rotates once each day. B. Earth revolves around the Sun once each year. C. The direction of Earth's axis in space precesses with a period of 26,000 years. D. Stars appear to move randomly in the local solar neighborhood. E. The universe is expanding. 1) Polaris will no longer be the North Star 1,000 years from now. Answer: C 2) In the year A.D. 15,000, Vega will be a better north star than Polaris. Answer: C 3) The Big Dipper will look different 100,000 years from now than it does today. Answer: D 4) The Moon rises in the east and sets in the west. Answer: A 5) The stars of Orion's belt rise in the east and set in the west. Answer: A 6) A million years from now, Alpha Centauri will no longer be the nearest star system to our own. Answer: D 13 Copyright © 2014 Pearson Education, Inc. 7) If Earth's axis had no tilt, would we still have seasons? Why or why not? Answer: We would no longer have seasons, because the Sun's light would hit at the same angle all throughout the year, depending only on where you lived. The slight change in distance between Earth and the Sun during the year would not produce much of an effect. 8) Consider the following statement, and explain whether or not it is sensible: If you had a very fast spaceship, you could travel to the celestial sphere in about 100 years. Answer: This statement does not make sense because the celestial sphere is a concept and not a physical object. 9) Consider the following statement, and explain whether or not it is sensible: When I looked into the dark fissure of the Milky Way with my binoculars, I saw what must have been a cluster of distant galaxies. Answer: This statement does not make sense because we cannot see through the band of light we call the Milky Way to external galaxies; the dark fissure is gas and dust blocking our view. 10) Why does the Milky Way appear as a band of light in the sky? Answer: The solar system lies in the outer parts of the thin disk of a spiral galaxy. Thus when we look along the plane of the disk, we see large numbers of stars that, to the naked eye, merge into a band of light. When we look out of the plane of the disk, there are very few stars and the night sky is much darker. 11) Consider the following statement, and explain whether or not it is sensible: Although all the known stars appear to rise in the east and set in the west, we might someday discover a star that will appear to rise in the west and set in the east. Answer: This statement does not make sense. The stars aren't really rising and setting, they only appear to rise in the east and set in the west because the Earth rotates. 12) At what altitude and in what direction in your sky does the north or south celestial pole appear? Answer: Answers will vary with your latitude; latitude = altitude of NCP (or SCP in Southern Hemisphere). 13) Consider the following statement, and explain whether or not it is sensible: My sign is Ursa Major because the Sun was in Ursa Major when I was born. Answer: Not sensible: The Sun appears only in the constellations of the zodiac–and Ursa Major is not one of these. 14) Consider the following statement, and explain whether or not it is sensible: Last night I saw Jupiter in the constellation Ursa Major. Answer: This statement does not make sense because Jupiter, like all the planets, is always found very close to the ecliptic in the sky. The ecliptic passes through the constellations of the zodiac, so Jupiter can appear to be only in one of the 12 zodiac constellations–and Ursa Major is not one of these. 14 Copyright © 2014 Pearson Education, Inc. 15) Answer each of the following questions for our local sky. A. Where is the north celestial pole in our sky? B. Is Polaris a circumpolar star in our sky? Explain. C. Describe the meridian in our sky. D. Describe the celestial equator in our sky. Answer: A. Answers will vary with latitude; here is a sample for 40°N: The north celestial pole appears at an altitude of 40°, in the direction due north. B. Yes, for any location in the Northern Hemisphere; no, for any location in the Southern Hemisphere. Polaris is circumpolar because it never rises or sets in our sky. It makes a daily circle, less than 1° in radius, around the north celestial pole. C. The meridian is a half-circle that stretches from the due south point on the horizon, through the zenith, to the due north point on the horizon. D. Answers will vary with latitude; here is a sample answer for 40°N: The celestial equator is a half-circle that stretches from the due east point on the horizon, through an altitude of 50° due south, to the due west point on the horizon. 16) Consider the following statement, and explain whether or not it is sensible: If you lived on the Moon, you'd see full Earth when we see new Moon. Answer: This is true, because at full Moon, Earth lies between the Sun and the Moon. Thus, an observer on the Moon would be looking at the night side of Earth. 17) Suppose you lived on the Moon near the center of the face that we see from Earth. During the phase of full Moon, what phase would you see for Earth? Would it be day or night at your home? Answer: During the full Moon, it would be daytime and you would see the phase of new Earth. 18) Suppose you lived on the Moon near the center