BROCK UNIVERSITY. Test 2: July 2015 Number of pages: 9 Course: ASTR 1P02, Section 2 Number of students: 318

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1 BROCK UNIVERSITY Page 1 of 9 Test 2: July 2015 Number of pages: 9 Course: ASTR 1P02, Section 2 Number of students: 318 Examination date: 4 July 2015 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: A spiral galaxy has a small bright central region, and the intensity of its radiation varies on a time scale of minutes. It is most likely a galaxy. (a) barred spiral (b) irregular (c) radio (d) Seyfert 2. Astronomers deduce that the universe is expanding because they see (a) the disks of galaxies getting smaller over time. (b) the edge of the universe moving away from us. (c) redshifts in the spectral lines of distant galaxies. (d) distant galaxies dissolve, pulled apart by the expansion of space. 3. Irregular galaxies are the brightest galaxies in the universe. 4. Elliptical galaxies contain a relatively large amount of gas and dust. 5. When two galaxies collide most of their stars are destroyed in star-star collisions. (c) [Galaxies do not collide.]

2 ASTR 1P02 July 2015 Page 2 of 9 6. Which type of elliptical galaxy deviates most from a spherical shape? (a) E1 (b) E3 (c) E5 (d) E7 7. The size of the region responsible for the large luminosity of a quasar can be estimated from (a) its distance. (b) the period of its luminosity variation. (c) its redshift. (d) its mass. 8. The distance of galaxy A is three times the distance of galaxy B. The recession speed of A is about the recession speed of galaxy B. (a) three times (b) nine times (c) one third of (d) one ninth of 9. A galaxy has a bright linear feature in its central region. What kind of galaxy is it most likely to be? (a) spiral (b) barred spiral (c) elliptical (d) irregular 10. A large galaxy contains mostly old Population II stars spread smoothly throughout its volume, but it has little dust or gas. What type of galaxy is it most likely to be? (a) spiral (b) barred spiral (c) elliptical (d) irregular

3 ASTR 1P02 July 2015 Page 3 of Rich galaxy clusters consist mostly of (a) spiral Sc galaxies. (b) barred spiral galaxies. (c) elliptical galaxies and Sa spirals. (d) active galaxies. 12. 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 elliptical galaxies with multiple nuclei.] 13. The number of spiral galaxies we observe is the number of elliptical galaxies we observe. (a) about twice (b) about 100 times (c) about half (d) about 1/100th 14. Astronomers use Cepheid variables to measure (a) rotation curves of galaxies. (b) velocities of galaxies. (c) distances to nearby galaxies. (d) masses of galaxies. 15. Which distance indicators are used to determine the distances of the most distant galaxies in the Universe? (a) Cepheid variables. (b) Globular clusters. (c) Parallax shifts. (d) Type Ia supernovae. 16. Galaxies with active galactic nuclei form the majority of galaxies that we observe.

4 ASTR 1P02 July 2015 Page 4 of The cosmic microwave background radiation was first observed by (a) Vesto Slipher. (b) Edwin Hubble. (c) Arno Penzias and Robert Wilson. (d) Harlow Shapley. 18. Who was the first to measure the speeds of nearby galaxies? (a) Vesto Slipher. (b) Edwin Hubble. (c) Arno Penzias and Robert Wilson. (d) Harlow Shapley. 19. What evidence supports the Big Bang theory? (a) massive black holes in galactic centres (b) clustering of galaxies (c) low-intensity microwave radiation from all directions (d) quasars 20. Quasars are unusual because although they appear star-like, unlike stars they emit large amounts of (a) quarks. (b) quasinos. (c) quasalinos. (d) radio waves. 21. Which of these spiral galaxies contains the highest amount of gas and dust? (a) Sa. (b) Sb. (c) Sc. (d) Sd. 22. Which of the following Cepheid variables has the highest peak luminosity? (a) One which has a luminosity variation with a period of 3 days. (b) One which has a luminosity variation with a period of 10 days. (c) One which has a luminosity variation with a period of 30 days. (d) One which has a luminosity variation with a period of 50 days.

5 ASTR 1P02 July 2015 Page 5 of At present the value of the parameter Ω resulting from ordinary matter, dark matter and dark energy is (a) less than 0.1 (i.e. the universe has a negative curvature). (b) about equal to 1 (i.e. the universe is approximately flat). (c) greater than 10 (i.e. the universe has a positive curvature). (d) [Astronomers currently have no idea about the value of the parameter Ω.] 24. Recombination of electrons with nuclei took place when the temperature of the universe dropped to about (a) 300,000 K. (b) 30,000 K. (c) 3,000 K. (d) 300 K. 25. Since the time of recombination the universe has expanded by about a factor of The Universe became transparent to radiation about 3 minutes after the Big Bang. 27. COBE (a) is a satellite used to detect neutrino emissions from the Sun, providing further precision evidence for the theory of stellar nucleosynthesis. (b) is currently out of commission due to a torn rotator cuff on the satellite s photonshooting mechanism. (c) is a satellite used to detect cosmic microwave background radiation, providing further precision evidence for the Big Bang theory. (d) is a satellite used to detect cosmic gamma-ray background emissions, providing further precision evidence for the theory of black-hole event horizons. 28. The age of the universe is about (a) 14 thousand years. (b) 14 million years. (c) 14 billion years. (d) 14 trillion years.

6 ASTR 1P02 July 2015 Page 6 of If the value of the cosmological parameter Ω were greater than 1 the global curvature of spacetime would be (a) positive. (b) zero. (c) negative. (d) impossible to determine. 30. Dark energy tends to (a) draw matter in to itself, much like a black hole, and therefore tends to cause the universe to contract. (b) be chaotic, and scatters matter in all directions, and therefore tends to increase the negentropy of the universe. (c) concentrate in the darkest regions of space, the voids between filaments connecting super clusters of galaxies. (d) oppose gravity, and therefore tends to cause the universe to expand. 31. The Andromeda galaxy, M31, is about from our galaxy. (a) 2.5 million km (b) 2.5 million AU (c) 2.5 million light years (d) [The Andromeda galaxy is part of our galaxy.] 32. All galaxies other than the Milky Way are (a) much smaller satellite galaxies of the Milky Way. (b) independent star systems containing a huge number of stars, comparable to the Milky Way. (c) just clouds of gas and dust, and not collections of stars similar to the Milky Way. (d) called galaxies just by historical accident; they are really nebulae, not galaxies. 33. The classification of galaxies into three main types, spiral, elliptical, and irregular, is due to (a) Edwin Hubble. (b) Vesto Slipher. (c) Jocelyn Bell. (d) Mike degrasse Tyson.

7 ASTR 1P02 July 2015 Page 7 of One of the primary difficulties in studying galaxies in the early 20th century was due to the great (a) shyness of galaxies, which means they like to hide from view. (b) cost of bribing paparazzi to spy on them. (c) distances of galaxies from us. (d) the great size of galaxies. 35. The redshift of Galaxy A is twice the redshift of Galaxy B. Therefore, the recession speed of Galaxy A is the recession speed of Galaxy B. (a) twice (b) four times (c) one-half (d) one-quarter 36. The recession speed of Galaxy A is twice the recession speed of Galaxy B. Therefore, the distance of Galaxy A from us is the distance of Galaxy B from us. (a) twice (b) four times (c) one-half (d) one-quarter 37. Spiral galaxies typically contain (a) mostly discarded screws, nuts, and bolts. (b) mostly young stars. (c) mostly old stars. (d) a mix of young and old stars. 38. Elliptical galaxies typically contain (a) warehouses full of eggs that the Easter Bunny distributes. (b) mostly young stars. (c) mostly old stars. (d) a mix of young and old stars. 39. Collisions between galaxies (a) could be a lot safer if only they would wear their seatbelts. (b) could be drastically reduced if only galaxies drank less alcohol. (c) are extremely rare, and have almost never happened. (d) play an important role in the evolution of some galaxies.

8 ASTR 1P02 July 2015 Page 8 of Active galaxies (a) are those that work out frequently, eat right, and stay in good shape. (b) tend to have a lot more dates than inactive galaxies. (c) have stars that move about with much greater speeds. (d) emit an abnormally large amount of energy from tiny regions in their cores. 41. Cosmology is the study of (a) stellar motions within galaxies. (b) galactic motions within clusters and super-clusters. (c) the structure and evolution of galaxies. (d) the structure and evolution of the universe as a whole. 42. Soon after the formation of the universe, its average density was (a) much less than it is today. (b) about the same as it is today. (c) much greater than it is today. (d) [It s impossible to say, because nobody was around back then to measure it.] 43. Long ago, when galaxies were young, the average distance between two galaxies was (a) much less than it is today. (b) about the same as it is today. (c) much greater than it is today. (d) [It s impossible to say, because nobody was around back then to measure it.] 44. Because galaxies are observed to move away from us, in general, and the farther away they are the faster they are moving away, this is evidence that (a) the Earth is at the centre of the universe. (b) the Earth is far from the centre of the universe. (c) the distant galaxies are at the centre of the universe. (d) [No such conclusion can be drawn from this observation.] 45. The recombination era was that time in the evolution of the universe when (a) the ABA and the NBA combined to form a single, unified association. (b) the WHL and the NHL combined to form a single, unified league. (c) the AFL and the NFL combined to form a single, unified league. (d) protons, neutrons, and electrons combined to form atoms of hydrogen and helium.

9 ASTR 1P02 July 2015 Page 9 of Models of helium formation in the early universe are tested by measuring the abundance of helium in (a) hot air emitted by Donald Trump. (b) the youngest known stars. (c) the oldest known stars. (d) the Sun. 47. The greater the distance of a galaxy, the greater is the observed redshift in its spectrum. (a) True (b) False (c) [There is no connection between redshift and distance.] 48. The age of the universe as estimated by Hubble s law is equal to (a) the Hubble constant, H. (b) the reciprocal of the Hubble constant, 1/H. (c) [There is no connection between the Hubble constant and the age of the universe.] 49. The expansion rate of the universe is currently (a) increasing. (b) decreasing. (c) constant. (d) unknown. 50. Whether the universe expands forever, or eventually re-collapses depends on its (a) average temperature and total mass. (b) average density and total angular momentum. (c) average temperature and total moment of inertia. (d) average density and expansion rate.