BROCK UNIVERSITY. Test 2: June 2016 Number of pages: 10 Course: ASTR 1P02, Section 2 Number of students: 359

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1 BROCK UNIVERSITY Page 1 of 10 Test 2: June 2016 Number of pages: 10 Course: ASTR 1P02, Section 2 Number of students: 359 Examination date: 25 June 2016 Time limit: 50 min Time of Examination: 13:00 13:50 Instructor: S. D Agostino Answer all questions on the scantron sheet provided. No aids permitted except for a non-programmable calculator. Each question is worth 1 mark. Total number of marks: 50. DO NOT WRITE YOUR ANSWERS ON YOUR QUESTION PAGE. DOING SO WILL RESULT IN AN ASSIGNED GRADE OF ZERO. 1. The general shape of elliptical galaxies is (a) rectangular. (b) oval. (c) disk-like. (d) irregular. 2. Elliptical galaxies contain mostly (a) old stars and tend to be red. (b) old stars and tend to be blue. (c) young stars and tend to be red. (d) young stars and tend to be blue. 3. Elliptical galaxies typically contain (a) a lot of gas and dust. (b) a lot of dust, but very little gas. (c) an unusually large amount of gas, but very little dust. (d) very little gas and dust. 4. A spiral galaxy (a) is a rotating ellipsoid, much like a spiral-thrown football pass. (b) has spiral arms that appear much like a DNA molecule, or a wood screw. (c) has a spherical membrane surrounding a spiral nucleus. (d) [None of the above.]

2 ASTR 1P02 June 2016 Page 2 of Galaxies are located (a) within the Milky Way. (b) outside of the Milky Way. (c) [Some galaxies are within the Milky Way and others are outside of the Milky Way.] 6. Galaxies consist of (a) sugar and spice and everything nice. (b) vast clouds of dust and luminous gas, but no stars. (c) some gas and dust, and many constellations. (d) an enormous number of stars, and also many other objects. 7. For galaxies that are not too distant, astronomers use to measure their distances from us. (a) Type Ia supernovae. (b) parallax measurements. (c) the method of Cepheid variables. (d) the method of globular clusters. 8. The distances to galaxies more than about 100 million light years away can be determined using (a) Type Ia supernovae. (b) parallax measurements. (c) the method of Cepheid variables. (d) the method of globular clusters. 9. The distances to the most distant galaxies are determined using (a) Type Ia supernovae. (b) parallax measurements. (c) the method of Cepheid variables. (d) the method of globular clusters.

3 ASTR 1P02 June 2016 Page 3 of In 1929, a relationship between a galaxy s distance from us and its recession speed was discovered by (a) Edwin Hubble. (b) Harlow Shapley. (c) Vera Rubin. (d) Fritz Zwicky. 11. One of the conclusions drawn from the relationship mentioned in the previous question is that (a) the universe is expanding. (b) the decreases in rotation rates of pulsars is consistent with the predictions of general relativity. (c) the universe is infused with dark matter. (d) the large-scale structure of the universe contains filaments. 12. Galaxies that contain a chaotic mix of gas and dust with no obvious nucleus and no spiral arms are called (a) chaotic galaxies. (b) clustered galaxies. (c) inactive galaxies. (d) irregular galaxies. 13. Observations show that the more distant a galaxy is, typically (a) the more slowly it moves away from us. (b) the more rapidly it moves away from us. (c) the larger is its absolute luminosity. (d) the smaller is its absolute luminosity. 14. The classification of elliptical galaxies as E0, E1, etc., is based on their (a) apparent brightness. (b) apparent shape. (c) luminosity. (d) recession speed. (e) redshift.

4 ASTR 1P02 June 2016 Page 4 of The distance between two galaxies is typically the distance between two stars in the Milky Way. (a) much less than (b) slightly less than (c) about the same as (d) slightly greater than (e) much greater than 16. One possible result of a galaxy collision is (a) the two galaxies might unfriend each other on Cosmosbook. (b) one of the galaxies might give birth to an infant galaxy nine eons later. (c) one of the galaxies might strip gas and dust away from the other galaxy. (d) the dark matter in one of the galaxies might absorb dark energy from the other galaxy. 17. An active galaxy (a) has many stars with unusually high orbital velocities. (b) has an unusually large number of supernovae. (c) emits an unusually large amount of energy from a tiny region in its core. (d) has an unusually large number of variable stars. 18. A quasar is a very distant, very luminous (a) active galaxy. (b) planetary nebula. (c) supernova. (d) white dwarf. 19. Jets that emit electromagnetic radiation are found near some (a) quasars. (b) radio galaxies. (c) Seyfert galaxies. (d) [All of the above.] (e) [None of the above.]

5 ASTR 1P02 June 2016 Page 5 of Quasars are unusual because although they appear star-like, unlike stars they emit large amounts of (a) neutrons. (b) protons. (c) radio waves. (d) tachyons. 21. A simple resolution to Olbers s paradox, suggested by the poet Edgar Allan Poe, and later generally accepted after much scientific discussion, is that (a) the age of the universe is finite. (b) interstellar dust blocks light from distant stars. (c) light from very distant stars gradually loses energy over its long journey (the tired-light hypothesis). (d) there are a lot fewer stars than astronomers say there are, an obvious error that mainstream astronomers will not admit to making. 22. Evidence suggests that galaxies formed about years ago. (a) 13 million (b) 130 million (c) 1.3 billion (d) 13 billion 23. According to the Big Bang theory, neutral hydrogen atoms formed (a) as soon as the Big Bang occurred. (b) about 380 days after the Big Bang. (c) about 380 years after the Big Bang. (d) about 380 thousand years after the Big Bang. 24. Cosmic background radiation was emitted by (a) the first stars formed after the big bang. (b) the hot dense material in the early universe. (c) quasars. (d) radio galaxies and Seyfert galaxies.

6 ASTR 1P02 June 2016 Page 6 of Strong evidence for the Big Bang theory is provided by observations of (a) type Ia supernovae. (b) Cepheid variables. (c) the brightest quasars. (d) cosmic background radiation. 26. The reciprocal of the Hubble constant gives an approximate value for (a) the total mass of the universe. (b) the age of the universe. (c) the total mass and energy content of the universe. (d) the total mass, energy content, and dark matter content of the universe. 27. If the average density of matter in the universe is below a certain threshold value, called the critical density, then the universe will (a) expand for a while, but slow down, reverse, and eventually collapse in a Big Crunch. (b) continue to expand indefinitely, but the expansion rate approaches zero more and more closely as time passes. (c) continue to expand indefinitely, but the expansion rate is approximately constant. (d) [None of the above.] 28. If the average density of matter in the universe is equal to a certain threshold value, called the critical density, then the universe will (a) expand for a while, but slow down, reverse, and eventually collapse in a Big Crunch. (b) continue to expand indefinitely, but the expansion rate approaches zero more and more closely as time passes. (c) continue to expand indefinitely, but the expansion rate is approximately constant. (d) [None of the above.] 29. If the average density of matter in the universe is above a certain threshold value, called the critical density, then the universe will (a) expand for a while, but slow down, reverse, and eventually collapse in a Big Crunch. (b) continue to expand indefinitely, but the expansion rate approaches zero more and more closely as time passes. (c) continue to expand indefinitely, but the expansion rate is approximately constant. (d) [None of the above.]

7 ASTR 1P02 June 2016 Page 7 of The universe s expansion appears to be accelerating, apparently as a result of (a) dark chocolate. (b) dark energy. (c) dark matter. (d) dark space. 31. From which evidence do astronomers deduce that the universe is expanding? (a) They can see the disks of galaxies getting smaller over time. (b) They see a redshift in the spectral lines of distant galaxies. (c) They detect cosmic background X-ray radiation. (d) They can see distant galaxies dissolve, pulled apart by the expansion of space. (e) [All of the above.] 32. A supercluster (a) is an extremely rich cluster of galaxies. (b) is a cluster of extremely large galaxies. (c) typically contains between 5 and 25 clusters of galaxies. (d) typically contains between 5,000 and 25,000 clusters of galaxies. 33. Observations of elliptical galaxies with multiple nuclei is evidence for (a) the density wave theory. (b) galaxy mergers. (c) the general theory of relativity. (d) [There are no known elliptical galaxies with multiple nuclei.] 34. Radio galaxies are typically certain that emit large amounts of radio waves. (a) spiral galaxies (b) elliptical galaxies (c) irregular galaxies (d) Hubble galaxies

8 ASTR 1P02 June 2016 Page 8 of If Hubble s constant were half as large as we think it is, then the universe would be as we think it is. (a) 4 times as old (b) 2 times as old (c) the same age (d) 1/2 as old (e) 4 times as old 36. At the time of the Big Bang, (a) the universe was transparent. (b) the universe was very cool. (c) hydrogen fused to form helium. (d) galaxies began to form. (e) stellar cores began to form. 37. The cosmological constant, Λ, describes the overall curvature of space, and is connected to the overall density of matter, Ω, of the universe. If the overall density of matter is greater than the critical value, then the overall curvature of space is (a) positive. (b) zero. (c) negative. (d) infinite. 38. The universe became transparent to light (a) when free electrons and free protons combined. (b) when neutrinos began to oscillate. (c) when photons combined with anti-photons to form gamma rays. (d) when stellar nucleosynthesis began. 39. The cosmic background radiation currently has its peak in the part of the electromagnetic spectrum. (a) ultraviolet (b) infrared (c) microwave (d) radio wave

9 ASTR 1P02 June 2016 Page 9 of The observed distribution of chemical elements in the early universe of is strong evidence for the Big Bang theory. (a) about 75% hydrogen, 25% helium, and just traces of other elements, (b) about 65% hydrogen, 35% helium, and just traces of other elements, (c) about 55% hydrogen, 45% helium, and just traces of other elements, (d) about 45% hydrogen, 55% helium, and just traces of other elements, 41. For most of the time since the beginning of the Big Bang, conditions were (a) not much different from today. (b) much colder than today. (c) similar to the inside of an atomic nucleus. (d) similar to the core of a star. (e) similar to the surface of a star. 42. The redshift of Galaxy A is five times the redshift of Galaxy B. Therefore, the recession speed of Galaxy A is the recession speed of Galaxy B. (a) twenty-five times (b) five times (c) one-fifth (d) one-twenty-fifth 43. The recession speed of Galaxy A is three times the recession speed of Galaxy B. Therefore, the distance of Galaxy A from us is the distance of Galaxy B from us. (a) nine times (b) three times (c) one-third (d) one-ninth 44. Why might a galaxy such as M31 (Andromeda) have a blueshifted spectrum instead of a redshifted spectrum? (a) It is relatively close to us, and so the blueshift due to its local motion is greater than the cosmological redshift effect. (b) It is relatively far from us, and so the blueshift due to its local motion is greater than the cosmological redshift effect. (c) It contains a large number of quasars. (d) It contains an exceptionally large central black hole.

10 ASTR 1P02 June 2016 Page 10 of The most probable result of a collision between two elliptical galaxies is (a) complete destruction of most of the stars. (b) the formation of a single spiral galaxy. (c) the formation of a single open cluster. (d) the formation of a ring galaxy. (e) [Galaxy collisions never occur.] 46. The total mass of all the stars in a typical galaxy accounts for (a) almost all of the total mass of the galaxy. (b) most of the total mass of the galaxy. (c) about half of the total mass of the galaxy. (d) a small fraction of the total mass of the galaxy. 47. One popular possible explanation for dark matter is that it consists of (a) weakly-interacting massive particles. (b) strongly-interacting massive particles. (c) weakly-interacting massless particles. (d) strongly-interacting massless particles. 48. A famous catalogue of astronomical objects was compiled by so that astronomers wouldn t confuse them with comets. (a) Jari Kurri (b) Charles Messier (c) David Semenko (d) Esa Tikkanen 49. Which fact is explained by a brief period of inflation? (a) The high uniformity of the cosmic background radiation in various directions. (b) The large number of black holes in the universe. (c) The ratio of hydrogen to helium in very old stars. (d) The ratio of matter to anti-matter in the universe. 50. It is estimated that our solar system formed about after the Big Bang. (a) 10 years (b) 10 thousand years (c) 10 million years (d) 10 billion years