Exam 13

1 Name: Intro Astro: Stars & Cosmology: Exam 1 Instructions: There are 72 multiple-choice problems each worth 1 mark for a total of 72 marks altogether. Choose the BEST answer, completion, etc. Read all responses carefully. NOTE long detailed responses won’t depend on hidden keywords: keywords in such responses are bold-faced capitalized. This is a CLOSED-BOOK / NOTES / WEB / OUTSIDE-WORLD- ACCESS exam. NO cheat sheets allowed. NO outside sources of any kind allowed. You can use only what is inside your mind. Calculators and cell phones are permitted ONLY for calculations. Remember, it is shameful to cheat—you are trying to steal from your fellow students. The exam is out of 72 marks altogether and is a 75-minute exam. 1. “Let’s play Jeopardy ! For $100, the answer is: Stonehenge and many other prehistoric monuments suggest that the makers were doing this.” What is/are , Alex? a) special relativity calculations b) orbital physics c) simple alignment astronomy d) casting horoscopes e) receiving alien visitors from outer space 2. Stonehenge demonstrates that some prehistoric people: a) could predict eclipses. b) knew the northernmost rising location of the Sun. c) knew nothing of astronomy. d) knew more than the ancient Greeks about the universe. e) suffered from back pain. 3. The ancient Babylonians were using a sexagesimal (number) system as early as circa 1800 BCE. We do not know why, but it may well have been to save labor in division. The many whole number factors of 60 (1 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, and 60 for a total of 12 factors) simplifies many division problems. The sexagesimal system seems to have been used consistently only for mathematical and astronomical purposes. For everyday use, the Babylonians often or maybe mainly used other systems including the ubiquitous decimal system: counting on fingers is as old as the hills so to say. In the last centuries BCE the sexagesimal system was taken over into astronomy. Using a large base number with a lot of factors has advantages. But one needs a lot of symbols for all the numerals unless one uses some subsidiary base which is what the Babylonians did: 10. In any case 10 as a base has nothing very special to recommend it, except for the old (very old) finger exercise. As a non-finger exercise, subtract 61 ◦ 43 ′ 14 ′′ from 120 ◦ 41 ′ 03 ′′ . Recall that ′ stands for arcminutes and ′′ for arcseconds. HINT: If sexagesimal subtraction seems too tricky, you can try sexagesimal addition to recover 120 ◦ 41 ′ 03 ′′ . a) 182 ◦ 24 ′ 17 ′′ . b) 58 ◦ 57 ′ 49 ′′ . c) 58 ◦ 31 ′ 14 ′′ . d) 59 ◦ 51 ′ 49 ′′ . e) 58 ◦ 51 ′ 14 ′′ .

2 4. The ancient Greek Presocratic philosophers: a) may have hypothesized a spherical Earth in order to explain the daily rotation of the celestial sphere. But it is equally likely that they thought that a spherical Earth was proven by the axioms of geometry. b) may have hypothesized a spherical Earth in order to explain the daily rotation of the celestial sphere. Thales of Miletus then used the spherical Earth theory to predict a solar eclipse. c) may have hypothesized a spherical Earth because they thought the Earth needed to be spherical in order to be in balance at the center of the cosmos. Aristotle (384–322) later summarized empirical arguments for the spherical Earth. These included the varying celestial locations of the stars and planets relative to the horizon as one moved north-south and the fact that the Earth’s shadow on the Moon in a lunar eclipse was always round. However, ARISTOTLE went on to affirm that Greece must be on top of the spherical Earth because the ground in Greece was nearly level. d) may have hypothesized a spherical Earth because they thought the Earth needed to be spherical in order to be in balance at the center of the cosmos. Aristotle (384–322) later summarized empirical arguments for the spherical Earth. These included the varying celestial locations of the stars and planets relative to the horizon as one moved north-south and the fact that the Earth’s shadow on the Moon in a lunar eclipse was always round. However, PTOLEMY went on to affirm that Greece must be on top of the spherical Earth because the ground in Greece was nearly level. e) may have hypothesized a spherical Earth because they thought the Earth needed to be spherical in order to be in balance at the center of the cosmos. Aristotle (384–322) later summarized empirical arguments for the spherical Earth. These included the varying celestial locations of the stars and planets relative to the horizon as one moved north-south and the fact that the Earth’s shadow on the Moon in a lunar eclipse was always round. 5. A major obstacle that ancient Greek astronomers had in trying to determine the nature of the Solar System was: a) the eastward motion of the planets. b) the inability to measure any distances beyond Pluto. c) the inability to measure any distances beyond the Moon. d) the lack of all theoretical biases. e) the lack of geometrical skills. 6. Aristotelian cosmology: a) consisted of perfect eternal cubes rotating about the Earth. b) put the Earth at the center of the cosmos. The planets and fixed stars were located on sets of solid spheres that rotated about the Earth. The celestial phenomena were eternal exactly repeating motions. Beyond the sphere of the fixed stars was a CHAOS of primordial material in which were embedded other finite cosmoses. c) put the Earth at the center of the cosmos. The planets and fixed stars were located on sets of solid spheres that rotated about the Earth. The celestial phenomena

3 were eternal exactly repeating motions. Beyond the sphere of the fixed stars was NOTHING , not even empty space. The universe was finite. d) was DISCARDED by everyone in the medieval Islamic period. It put the Earth at the center of the cosmos. The planets and fixed stars were located on sets of solid spheres that rotated about the Earth. The celestial phenomena were eternal exactly repeating motions. Beyond the sphere of the fixed stars was NOTHING , not even empty space. The universe was finite. e) was never seriously considered again after Ptolemy’s time. 7. In modern times (which here we mean to be after circa 1450), who first proposed the heliocentric theory of the solar system? a) Nicolaus Copernicus (1473–1543). b) Thomas Digges (c. 1546–1595). c) Tycho Brahe (1546–1601). d) Galileo Galilei (1564–1642). e) Isaac Newton (1643–1727). 8. A key reason (perhaps the most important reason) that led Copernicus to propose the heliocentric Solar System was to: a) get rid of uniform circular motion. b) appease the Sun god. c) answer Galileo’s insult. d) get a prediction of the relative positions of the planets. e) prove that the universe was infinite. 9. Apparent retrograde motion is: a) the westward motion of a star on the sky. b) the westward motion of a planet on the sky. c) the eastward motion of a planet on the sky. d) the eastward motion of a star on the sky. e) the result of an inter-planetary collision. 10. If a planet has a mean distance from the Sun of 9 astronomical units, what is its orbital period in years? a) 28 years. b) 3 years. c) 9 years. d) 81 years. e) 27 years. 11. Galileo’s discovery of the moons of Jupiter: a) had no bearing on the debate over the Copernican theory. b) meant that the Earth was the center of Jupiter’s orbit. c) explained the full phases of Venus. d) meant that the Earth was not the physical center of all motion in the Solar System, and that Earth could have a moon and still be on an EPICYCLE . e) meant that the Earth was not the physical center of all motion in the Solar System, and that Earth could have a moon and still be a PLANET . 12. Could heliocentrism be proven to be physically correct in circa 1610? By physically correct we mean showing that the planets geometrically orbited the Sun AND that this structure (i.e., the structure of the Solar System) was derivable from physical law: i.e., that the planets ”physically” orbited the Sun.

4 a) Yes. Galileo’s telescopic discoveries were proof. b) Yes. Kepler’s 3 laws of planetary motion were proof. c) Yes. Galileo and Kelper’s work combined constituted proof. d) No. Only Newton’s physics published 1687 constituted proof. e) No. Only Einstein’s general relativity published 1915 constituted proof. 13. “Let’s play Jeopardy ! For $100, the answer is: This person’s work made astronomy in a sense and to a degree an experimental science in that he/she showed that the same physics applies on Earth and in the heavens.” Who is , Alex? a) Marguerite de Navarre (1492–1549) b) Giordano Bruno (1548–1600) c) Galileo Galilei (1564–1642) d) Isaac Newton (1643–1727) e) Johann Sebastian Bach (1685–1750) 14. It is somewhat traditional or at least not unusual to begin a book or course on with a philosophical/historical/poetical statement. a) agronomy b) astronomy c) metallurgy d) proctology e) tautology 15. “Let’s play Jeopardy ! For $100, the answer is: An American astronomer of the 2nd half of the 20th century, famous for planetology and science popularization—arguably the most well known scientist of his time.” Who is , Alex? a) Albert Einstein (1879–1955) b) George Gamow (1904–1968) c) Richard Feynman (1918–1988) d) Carl Sagan (1934–1996) e) Brian Greene (1963–) 16. The scientific method can be schematically described as a/an: a) square of theorizing and experiment/observation. b) integrative process. c) reductive process. d) a cycle of theorizing and experiment/observation. e) a pointless pursuit. 17. In scientific theorizing, a rule that has come to be accepted is “Pluralitas non est ponenda sine necessitate,” i.e., “Plurality is not to be posited without necessity” which was stated by Medieval scholastic philosopher John Duns Scotus (c.1266– 1308). The rule is called Occam’s razor after another Medieval scholastic philosopher William of Occam (c.1287–1347), who said something similar. In fact the general idea was expressed by none other than Aristotle (384–322 BCE): “We may assume the superiority ceteris paribus (other things being equal) of the demonstration which derives from fewer postulates or hypotheses.” The essential idea in modern jargon is don’t introduce into theories hypotheses that: a) are needed. b) both needed and not needed. c) are not needed. d) that neither needed nor not needed. e) not purely philosophical. 18. “Let’s play Jeopardy ! For $100, the answer is: This 17TH CENTURY FRENCH scientist gave an early (and probably the first) statement of the falsifiabilty doctrine— which has been much debated, but at least with qualifications has been accepted by