BROCK UNIVERSITY. Final Exam: July 2016 Number of pages: 18 Course: ASTR 1P02 Number of students: 351

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1 BROCK UNIVERSITY Page 1 of 18 Final Exam: July 2016 Number of pages: 18 Course: ASTR 1P02 Number of students: 351 Examination date: 9 July 2016 Time limit: 2 hours Time of Examination: 8:00 10:00 Instructor: S. D Agostino Answer all questions on the scantron sheet provided. No aids permitted except for a non-programmable calculator (this regulation does not preclude special arrangements being made for students with disabilities). Translation dictionaries (e.g., English-French) or other dictionaries (thesaurus, definitions, technical) are not allowed. Use or possession of unauthorized materials or electronic devices will result in a charge of academic misconduct under the University s Academic Integrity Policy. Each question is worth 1 mark. Total number of marks: 50. Return both the exam script and your scantron sheet when you leave the exam room. DO NOT WRITE YOUR ANSWERS ON YOUR QUESTION PAGE. DOING SO WILL BE TREATED AS ACADEMIC MISCONDUCT. 1. When a star is in its stable, main-sequence phase, it is held together primarily by (a) gravity. (b) high gas pressure. (c) high core temperature. (d) high core density. 2. In a main-sequence star, the star s high core pressure is caused by (a) the star s high core gravity. (b) the star s high core temperature. (c) the star s high core mass. (d) the star s high core luminosity. 3. Heat flows from a star s core to its surface because of (a) the star s high core gravity. (b) the star s high core mass. (c) the star s high core electron flux. (d) the temperature difference between the core and surface.

2 ASTR 1P02 July 2016 Page 2 of The dramatic changes that occur towards the end of a high-mass star s lifetime are caused by (a) the star running out of fuel. (b) a tear in the fabric of space-time. (c) a balance of pressure and gravity resulting in hydrostatic equilibrium. (d) runaway chemical reactions in the star s core. 5. If the mass of Star A is significantly greater than the mass of Star B, then (a) Star A is ridiculed far more often on Interstellar TMZ. (b) the lifetime of Star A is greater than the lifetime of Star B. (c) the lifetime of Star A is less than the lifetime of Star B. (d) the two stars have the same lifetimes. 6. A nebula is (a) a distant galaxy blurred by interstellar aberrations. (b) a cloud of gas and dust that is observable at visible wavelengths. (c) a collection of debris orbiting the Sun near a planet s Lagrange point. (d) hot gas ejected in a stellar prominence. 7. Reflection nebulae are (a) blue. (b) red. (c) white. (d) yellow. 8. Emission nebulae are (a) blue. (b) red. (c) white. (d) yellow. 9. Giant molecular clouds, from which stars will eventually form, are (a) very hot and dense. (b) very hot and not very dense. (c) cold and dense. (d) cold and not very dense.

3 ASTR 1P02 July 2016 Page 3 of As a contracting protostar heats up, if the core temperature reaches then fusion of hydrogen into helium begins and the protostar becomes a main-sequence star. (a) 10 thousand degrees K (b) 10 million degrees K (c) 10 billion degrees K (d) 10 trillion degrees K 11. Whether a star will eventually explode in a supernova or have a quieter end depends primarily on the star s (a) density. (b) luminosity. (c) mass. (d) spectrum. 12. Stars with masses of less than about 0.08 solar masses never get hot enough to fuse hydrogen into helium, and are called (a) white dwarfs. (b) red dwarfs. (c) brown dwarfs. (d) black dwarfs. 13. Low-mass stars that are expected to eventually cool until they will emit almost no light will then be called (a) white dwarfs. (b) red dwarfs. (c) brown dwarfs. (d) black dwarfs. 14. The non-fusing core that remains immediately at the end of the lifetime of a mediummass star is called a (a) white dwarf. (b) red dwarf. (c) brown dwarf. (d) black dwarf.

4 ASTR 1P02 July 2016 Page 4 of Hydrostatic equilibrium is a balance between a star s (a) hydro force and static force. (b) hydroelectric force and magnetic force. (c) neutrino flux and magnetic dynamo. (d) internal pressure and gravity. 16. As fusion proceeds in the core of a star, the number of particles, and so the temperature of the core must to maintain core pressure. (a) increases, increase (b) increases, decrease (c) decreases, increase (d) decreases, decrease 17. A protostar is (a) a stellar remnant that consists mainly of protons. (b) the cool early stage of a forming star. (c) the cool cloud of gas and dust dispersed when a star explodes. (d) the hot core of a main-sequence star. 18. T Tauri stars are (a) young stars that have variable luminosity and outflowing gas. (b) young stars that have variable luminosity and inflowing gas. (c) old stars that have variable luminosity and outflowing gas. (d) old stars that have variable luminosity and inflowing gas. 19. The main-sequence lifetime of a star depends on its (a) mass and colour. (b) mass and spectrum. (c) mass and chemical composition. (d) mass and luminosity. 20. Although planetary nebulae are typically approximately spherical, they appear to us to be shaped somewhat like a (a) ring. (b) parabola. (c) cone. (d) disk.

5 ASTR 1P02 July 2016 Page 5 of If a collapsing star has a mass less than the Chandrasekhar limit, then it (a) usually spends a night in jail, with a stern warning not to do it again. (b) fails to leave the main sequence. (c) eventually becomes a white dwarf. (d) eventually becomes a neutron star or black hole. 22. White dwarfs typically have sizes that are approximately the size of (a) the Moon. (b) the Earth. (c) Jupiter. (d) the Sun. 23. Eventually, a white dwarf will stop emitting light, but this takes (a) several thousand years. (b) several million years. (c) several billion years. (d) several trillion years. 24. The surface temperatures of white dwarfs are approximately (a) tens of thousands of degrees. (b) hundreds of thousands of degrees. (c) millions of degrees. (d) tens of millions of degrees. 25. When rotating stars shrink, they typically (a) rotate faster. (b) rotate slower. (c) do not change their rotation rates. 26. A neutron star is a remnant of a (a) type Ia supernova. (b) type II supernova. (c) type III supernova. (d) type IV supernova.

6 ASTR 1P02 July 2016 Page 6 of A black hole is a remnant of a (a) type Ia supernova. (b) type II supernova. (c) type III supernova. (d) type IV supernova. 28. In an X-ray binary star, the object emitting the X-rays is (a) a main-sequence star. (b) a neutron star. (c) a red dwarf. (d) a white dwarf. 29. The helium flash is the onset of fusion of in the core of a star. (a) helium into carbon (b) hydrogen into helium (c) helium into boron (d) helium into beryllium 30. Distances to the most distant galaxies are determined using (a) the method of Cepheid variables. (b) Type Ia supernovae. (c) Type II supernovae. (d) stellar parallax. 31. The general shape of the Milky Way can be determined (a) by observations from Earth and satellites in Earth orbit. (b) only by observations made from outside the Milky Way galaxy. (c) by observations from Earth confirmed by observations from outside the Milky Way galaxy. 32. Our solar system is located (a) in the halo of the Milky Way, far from its disk. (b) in the bulge of the Milky Way, very near its centre. (c) in the disk of the Milky Way, about half-way from the centre to the edge. (d) about half-way between the Milky Way and the Large Magellanic Cloud.

7 ASTR 1P02 July 2016 Page 7 of The number of stars in the Milky Way is approximately (a) 100 thousand. (b) 100 million. (c) 100 billion. (d) 100 trillion. 34. The disk of the Milky Way contains (a) stars, star clusters, gas and dust. (b) stars, star clusters, but no gas and dust. (c) stars, gas and dust, but no star clusters. (d) stars, no gas and dust, and no star clusters. (e) gas and dust, but no stars or star clusters. 35. The halo of the Milky Way contains (a) stars, star clusters, gas and dust. (b) stars, star clusters, but no gas and dust. (c) stars, gas and dust, but no star clusters. (d) stars, no gas and dust, and no star clusters. (e) gas and dust, but no stars or star clusters. 36. The stars in the bulge of the Milky Way are similar to the stars in the halo, but the bulge also contains (a) some hot, luminous stars. (b) no very massive stars. (c) spiral arms. (d) no very young stars. 37. Dark matter was discovered by observing that (a) some unknown substances were exorcising regions of space haunted by ghostalinos. (b) there needs to be an opposite to balance light matter, and heavy matter has not been discovered. (c) some areas of space appear to be completely empty, but there must be something there, because nature abhors a vacuum. (d) the motions of disk stars (i.e., rotation curves) in spiral galaxies differed from those expected by applying Kepler s third law.

8 ASTR 1P02 July 2016 Page 8 of The period-luminosity relationship for Cepheid variables was first observed by (a) Jocelyn Bell. (b) Edwin Hubble. (c) Arno Penzias and Robert Wilson. (d) Henrietta Swan Leavitt. 39. We can observe the centre of the Milky Way galaxy using (a) visible light. (b) radio waves. (c) satellite exploration. (d) [None of the above.] (e) [Both (a) and (b).] 40. The amount of ordinary matter in the universe is currently thought to be the amount of dark matter. (a) much greater than (b) about the same as (c) much less than (d) [We currently have no idea about this.] 41. The Milky Way is (a) a giant molecular cloud. (b) a spiral galaxy. (c) an elliptical galaxy. (d) an irregular galaxy. 42. About of the mass of the solar system is contained in the Sun. (a) 50% (b) 65% (c) 80% (d) 99.9% 43. The mass of the Sun is about times the mass of the Earth. (a) 100 (b) 300 (c) 100,000 (d) 300,000

9 ASTR 1P02 July 2016 Page 9 of The planet closest to the Sun is (a) Earth. (b) Mars. (c) Mercury. (d) Venus. (e) Vulcan. 45. The cores of terrestrial planets are primarily composed of (a) hydrogen and helium. (b) iron and nickel. (c) molten lava. (d) rock. 46. The outer planets have a much higher concentration of than the inner planets. (a) hydrogen. (b) iron. (c) silicon. (d) uranium. 47. The age of the planets is about (a) 5 million years. (b) 50 million years. (c) 500 million years. (d) 5 billion years. 48. Jovian planets are typically than terrestrial planets. (a) warmer (b) colder 49. Accretion is a process in which (a) planetesimals break up into small particles due to tidal forces. (b) thermal processes transform the physical structure of rocks. (c) small particles stick together to form larger particles. (d) heavy elements are dispersed throughout the universe.

10 ASTR 1P02 July 2016 Page 10 of Comets are (a) cars that were driven on the planet Mercury in the 1960s. (b) snowballs ejected from the underworld. (c) chunks of frozen gases with solid particles mixed in. (d) rocks that have broken off from planets. 51. Small chunks of rock that fly through the solar system are called (a) meteorinos. (b) meteorites. (c) meteoroids. (d) meteors. 52. Small chunks of rock that leave a streak of light as they fly through Earth s atmosphere are called (a) meteorinos. (b) meteorites. (c) meteoroids. (d) meteors. 53. Small chunks of rock that have landed on Earth after coming from outer space are called (a) meteorinos. (b) meteorites. (c) meteoroids. (d) meteors. 54. The craters on Mercury and other planets are the result of (a) volcanic activity. (b) impacts by solar system debris. (c) wind erosion of softer overlying material. (d) escaping air bubbles during the molten phase.

11 ASTR 1P02 July 2016 Page 11 of The planet that is most similar to Earth, in both diameter and mass, is (a) Mars. (b) Mercury. (c) Neptune. (d) Venus. 56. Besides the Earth, the greenhouse effect is most apparent on (a) Jupiter. (b) Mars. (c) Saturn. (d) Venus. 57. As viewed from above the Earth s north pole, all planets spin counterclockwise except for (a) Venus and Uranus. (b) Jupiter and Saturn. (c) Mars and Neptune. (d) Mercury and Earth. 58. The two moons of Mars, Phobos and Deimos, are most likely (a) to be captured asteroids. (b) to have been ejected from Mars. (c) to have formed along with Mars from the same clump of gas and dust. (d) to have been meteorites. (e) to have been meteors. 59. Kepler s third law relates a planet s to its. (a) diameter, orbital period (b) diameter, rotational period (c) distance from the Sun, orbital period (d) distance from the Sun, rotational period 60. The planet in our solar system with the largest density is (a) Earth. (b) Jupiter. (c) Mars. (d) Saturn.

12 ASTR 1P02 July 2016 Page 12 of The best current theory we have for the formation of the solar system hypothesizes that the solar system formed because of (a) the explosion of a protostar. (b) the explosion of a protoplanet. (c) the explosion of a T-Tauri star. (d) the collapse of a spinning cloud of gas and dust. 62. Anomalies in galactic rotation curves have been attributed to the existence of (a) intergalactic filaments. (b) galactic clustering. (c) dark energy. (d) dark matter. 63. The halo of the Milky Way contains (a) very little gas and dust. (b) a lot of gas and dust. (c) a lot of gas, but no dust. (d) a lot of dust, but no gas. 64. On average, stars in the Milky Way s bulge and halo contain percentage of heavy elements than stars in its disk. (a) a greater (b) a lesser 65. The number of stars in a globular cluster is typically the number of stars in an open clusters. (a) much greater than (b) much less than 66. The first galaxies outside of the Milky Way were recognized as such (a) by ancient astronomers. (b) in the 1300s. (c) in the 1500s. (d) in the 1700s. (e) in the 1900s.

13 ASTR 1P02 July 2016 Page 13 of Elliptical galaxies typically contain (a) mainly younger stars. (b) mainly older stars. (c) a mix of young and old stars. 68. Spiral galaxies typically contain (a) mainly younger stars. (b) mainly older stars. (c) a mix of young and old stars. 69. Young blue stars are (a) common in most irregular galaxies, which also typically contain lots of interstellar gas and dust. (b) common in most irregular galaxies, which also typically do not contain very much interstellar gas and dust. (c) uncommon in most irregular galaxies, which also typically contain lots of interstellar gas and dust. (d) uncommon in most irregular galaxies, which also typically do not contain very much interstellar gas and dust. 70. Quasars are (a) galaxies that emit a very large number of quasalinos. (b) black holes that emit intense gamma rays. (c) starlike objects that emit a very large amount of energy, and also emit a very large amount of radio waves. (d) neutron stars that emit intense pulses of radiation. 71. MACHOs and WIMPs are hypotheses intended to explain (a) black hole thermodynamics. (b) galactic clustering. (c) dark energy. (d) dark matter. 72. Hubble s law describes a relationship between (a) the distance of a galaxy and its recession speed. (b) the size of a galaxy and its rotational speed. (c) the mass of a galaxy and its pulsation rate. (d) the colour of a galaxy and its average parallax.

14 ASTR 1P02 July 2016 Page 14 of From Hubble s law, one can conclude that distances between distant galaxies are typically (a) decreasing. (b) constant. (c) increasing. (d) [None of the above.] 74. One can infer whether a galaxy is moving away from us, or towards us, and its relative speed, by measuring the redshift in its (a) density. (b) mass. (c) parallax. (d) spectrum. 75. Galaxies typically occur (a) isolated far from each other. (b) in clusters. (c) in beehive-like patterns. (d) in crystal-like patterns. 76. If the universe were infinite, existed for a very long time, and was uniformly filled with stars, then you could conclude that (a) the night sky should not be dark. (b) the Sun should have died long ago. (c) the solar system should be considerably smaller. (d) the Milky Way should contain much more dust than it actually has. 77. The observation that the night sky is dark implies that (a) there are a lot fewer stars than astronomers say there are, an obvious error that mainstream astronomers will not admit to making. (b) interstellar dust blocks light from distant stars. (c) the age of the universe is finite. (d) light from very distant stars gradually loses energy over its long journey (the tired-light hypothesis).

15 ASTR 1P02 July 2016 Page 15 of The following observed properties of cosmic microwave background radiation provide strong evidence for the Big Bang theory of the formation of the universe. (a) its mass and density (b) its pressure and volume (c) its temperature and similarity in all directions (d) its tension and diameter 79. The cosmic microwave background radiation was first observed (a) by ancient astronomers. (b) in the 1300s. (c) in the 1500s. (d) in the 1700s. (e) in the 1900s. 80. An estimate for the age of the universe can be obtained by using (a) Hubble s law. (b) Newton s law. (c) the Stefan-Boltzmann law. (d) Wien s law. 81. The first stars and galaxies formed about after the Big Bang. (a) 100 years (b) 100 thousand years (c) 100 million years (d) 100 billion years (e) 100 trillion years 82. Observed fluctuations in the cosmic microwave background are currently, which implies that matter was almost uniformly distributed in the early years after the Big Bang. (a) tiny (b) enormous (c) [Such fluctuations have never been observed.]

16 ASTR 1P02 July 2016 Page 16 of The current temperature of the cosmic microwave background radiation is approximately (a) 3 K. (b) 30 K. (c) 300 K. (d) 3000 K. 84. If the average density of the universe is large enough, then the universe (a) will be able to kick sand in the faces of those other universes that have been bullying it in the past. (b) will experience accelerated expansion. (c) will expand indefinitely. (d) will eventually stop expanding and re-collapse into a highly compact state. 85. If the average density of the universe is small enough, then the universe (a) will be able to get a job advertising weight-loss products. (b) will slow its expansion. (c) will expand indefinitely. (d) will eventually stop expanding and re-collapse into a highly compact state. 86. The latest observations on the overall curvature of the universe suggest that the universe (a) is nearly flat. (b) is very strongly positively curved, like a sphere or egg. (c) is very strongly negatively curved, like a saddle. (d) has a large number of wormholes. 87. Helium production in the early Universe stopped about after the Big Bang. (a) 10 minutes (b) 10 years (c) 10 thousand years (d) 10 million years 88. Inflationary models of the Universe s evolution provide elegant solutions to (a) the goaltender problem and the power forward problem. (b) the horizon problem and the flatness problem. (c) the helium production problem and the lithium ionization problem. (d) the Hubble parameter problem and the Wien displacement problem.

17 ASTR 1P02 July 2016 Page 17 of Measurements of recession speeds of distant galaxies suggest that (a) distant galaxies are moving away from us. (b) distant galaxies are neither moving away nor moving towards us. (c) distant galaxies are moving towards us. 90. The tail of a comet is gas and dust (a) pulled off the comet by the Sun s gravity. (b) pulled off the comet by friction with the inter-planetary medium. (c) pushed off the comet by the Sun s heat and radiation pressure. (d) pushed off the comet by nuclear fusion in the comet s nucleus. 91. The bright streak of light seen when a small object from the solar system flies through the atmosphere is caused by (a) sunlight reflected from the object. (b) moonlight reflected from the object. (c) radioactive decay of material in the object. (d) frictional heating. 92. The source of most meteorites is (a) asteroids. (b) comets. (c) Mars. (d) material from the solar wind. (e) the Moon. 93. Most asteroids in the main asteroid location of the solar system have orbits that are (a) prograde, nearly circular, and near the ecliptic. (b) prograde, highly elliptical, and near the ecliptic. (c) retrograde, nearly circular, and near the ecliptic. (d) retrograde, highly elliptical, and might be near or far from the ecliptic. 94. The average spacing between asteroids in the main asteroid location of the solar system is about (a) 10 m. (b) 1 km. (c) 1 thousand km. (d) 1 million km.

18 ASTR 1P02 July 2016 Page 18 of Astronomers estimate the sizes of most asteroids by (a) observing their angular diameters using space telescopes. (b) timing how long they take to pass in front of stars. (c) determining their gravitational influence on other asteroids. (d) measuring the amount of light that they reflect. 96. Asteroids in the asteroid belt are made up of (a) iron. (b) silicates (rock). (c) organic compounds. (d) [All of the above.] 97. The mass of Pluto was determined by (a) measuring the effect of its gravity on the terrestrial planets. (b) observing its effect on a satellite that passed by. (c) determining the orbit of its satellite, Charon. (d) measuring how it bends light rays passing near it. 98. Most meteorites that strike the Earth are (a) irons. (b) woods. (c) stones. (d) stony-irons. 99. The nucleus of a comet resembles (a) a harbinger of doom. (b) a muddy baseball. (c) a sticky tarball. (d) a dirty snowball Most comets originate (a) in the Costa del Sol if they have short periods and in the asteroid belt if they have long periods. (b) in the Kuiper belt if they have short periods and in the Oort cloud if they have long periods. (c) in the Kuiper belt if they have long periods and in the Oort cloud if they have short periods. (d) in the asteroid belt if they have short periods and in the Costa del Sol if they have long periods.