Astronomy 1504 Section 10 Final Exam Version 1 May 6, 1999 Reminder: When I write these questions, I believe that there is one one correct answer. The questions consist of all parts a e. Read the entire question before selecting an answer. Just because a statement is true does not mean it answers the question. Take your time! 1. The solar nebula probably began to collapse because: (a) it began to rotate (b) it was mostly hydrogen and helium (c) the sun s gravity pulled it in (d) it was compressed, most likely by a nearby exploding star 2. Which of the following are arranged in order of increasing mass? (a) Mercury, Venus, Mars, Uranus (b) Mercury, Mars, Earth, Neptune (c) Mars, Mercury, Earth, Neptune (d) Earth, Mars, Uranus, Jupiter 3. During the formation of the solar system, one process which caused grains to grow was: (a) the collision and sticking together of two grains (b) gravitational encounters with Jupiter (c) radiation pressure from the newly formed sun (d) the decay of radioactive isotopes 4. The rotation of the solar nebula caused it to: (a) collapse (b) flatten (c) glow (d) differentiate 1
5. Why does the earth not have a carbon dioxide atmosphere? (a) the earth outgassed little carbon dioxide (b) plant life has removed most of the carbon dioxide (c) the earth could not hold its carbon dioxide (d) the oceans removed much of the carbon dioxide, and plant life continues to remove it 6. The most abundant gas in the earth s present atmosphere is: (a) carbon dioxide (b) nitrogen (c) oxygen (d) water vapor 7. The age of the earth is approximately: (a) 6x10 3 years (b) 5x10 7 years (c) 5x10 9 years (d) infinite 8. The earth developed a nickel-iron core because: (a) it melted and differentiated (b) it is mostly made of nickel and iron (c) the magnetic field pulled the nickel and iron to the center (d) of the tidal forces exerted by the moon and sun together 9. Which of these is thought to be the correct theory for the origin of the moon? (a) formation elsewhere in the solar system & capture by the earth (b) forming simultaneously as the earth in the solar nebula (c) capture of a passing comet by the earth (d) creation by the giant impact of a mars sized body 10. Which planet rotates on its side? (a) Neptune (b) Pluto (c) Uranus (d) Venus 11. Which Jovian satellite is thought to contain liquid water? (a) Europa (b) Io (c) Ganymede (d) Calisto 2
12. Once the basic planet building process was complete, what happened to left-over planetesimals? (a) most of them fell into the sun (b) many were pushed out of the solar system by radiation pressure (c) many collided with the newly formed planets (d) they were hauled away to be used in another solar system 13. Meteorite ALH84001: (a) Was found in Antarctica (b) Came to the earth from mars (c) shows evidence that mars had liquid water (d) may indicate the presence of bacteria on mars (e) all of the above 14. Meteorites are easy to find in Antartica, because: (a) it is very cold there (b) they travel with ice and get trapped up against mountains (c) the ice acts like a magnet for meteorites (d) none of the above 15. Life as we know it is based on: (a) hydrogen (b) helium (c) carbon (d) oxygen (e) silicon 16. The probability of a technological civilization forming around a 10 solar mass star is small because (a) the star and any planets around it would be too hot (b) the star and any planets around it would be too cool (c) the stellar lifetime would be too brief (d) such stars will be binary and will not have planetary companions 17. Why would we not expect to find intelligent life on planets in the habitable zone around main sequence B stars? (a) these stars do not live long enough for intelligent life to develop (b) such planets would be much too hot for life (c) such stars have too little metals for solid planets to form (d) in fact, B stars are probably our best candidates 3
18. When we observe very distant galaxies we are observing: (a) very young objects (b) very old objects (c) objects having the approximate age of the Milky Way (d) distant galaxies; no statement may be made about age 19. After hydrogen, the next most abundant element formed in the big bang was: (a) helium (b) oxygen (c) nitrogen (d) carbon (e) iron 20. The cosmological critical density is: (a) the density of matter in the Milky Way (b) the density at which an object becomes a black hole (c) the number density of galaxies in a typical cluster of galaxies (d) the density at the center of the big bang (e) the density of a flat universe 21. The cosmological principle states that: (a) cosmology is the most noble human activity (b) the universe is homogeneous and isotropic, on a large scale (c) everything that goes up must come down (d) the universe must have a boundary, somewhere 22. The existence of the cosmic microwave background radiation : (a) is not taken seriously by most astronomers (b) is observational evidence in support of the big bang (c) is only detected from the southern hemisphere (d) is most intense at ultraviolet wavelengths 23. The microwave background (T 3 K) is presently ascribed to: (a) supernova explosion (b) smoothed out radiation of nearby objects (c) the process of the formation of the sun and planets (d) red-shifted photons from a very early stage of the universe 4
24. The fact that the known extra-solar planets have Jupiter sized masses, but short periods: (a) Means they are very nearby their stars (b) Is a challenge to the condensation hypothesis of solar nebula theory (c) Means they likely have changed their orbits and moved inward toward their stars since their birth (d) all of the above 25. A planet will move fastest in its orbit when it is: (a) farthest from the sun (b) at its average distance from the sun (c) nearest to the sun (d) at either of the foci of its orbit 26. The difference between 3 He and 4 He is: (a) a neutron (b) a proton (c) an electron (d) a neutrino (e) a positron 27. The heavy elements in our bodies were formed: (a) mostly in a black hole (b) mostly in neutron stars (c) mostly the interior of stars (d) mostly in the big bang 28. Which of the following galaxy types would we not expect to find stars forming in? (a) ellipticals (b) spirals (c) irregulars (d) starburst (e) active 29. The units that astronomers express Hubble s constant in is km/s/mpc. Really this is a funny way of writing: (a) time (b) distance (c) 1/time (d) redshift 5
30. In class, I ve said the value that the OU astronomers like for H 0 is: (a) 100 ± 20 (b) 50 ± 5 (c) 75 ± 10 (d) 60 ± 10 31. We see a supernova in a galaxy that is 100 Mpc away. How long ago did the supernova actually occur? For the purpose of this question 1 ly = 3.3 pc. (a) 0 yr ago (b) 330 yr ago (c) 330,000 yr ago (d) 330,000,000 yr ago 32. The difference between a quasar and a Seyfert II galaxy is likely due to: (a) Different viewing angles (b) Quasar is an elliptical and Seyfert II is a spiral (c) Quasar has a smaller black hole than Seyfert II (d) Quasars are nearby and Seyfert II are far away 33. Why are the central engines in active galactic nuclei thought to be smaller than the solar system? (a) They contain black holes (b) They are very far away (c) They vary in brightness in only a few days or weeks (d) They appear to be point-like objects in the most powerful telescopes 34. Type Ia supernova showed us a surprising cosmological result in that: (a) We found the universe was expanding slower in the past than today (b) We found the universe was expanding faster in the past than today (c) They are thought to be explosions of a Chandrasekhar mass white dwarf (d) all of the above 35. At the end of Big bang nucleosynthesis, the universe was mostly composed of: (a) protons, helium, photons, electrons, and neutrinos (b) electrons and positrons (c) quarks, gluons, photons, electrons, postirons, and neutrinos (d) carbon, nitrogen, and oxygen 6
36. The position of the life zone around a star depends on: (a) The effective temperature of the star (b) Where the planets are (c) How old the star is (d) none of the above 37. Olbers paradox asks the question: (a) Why is the universe curved? (b) Why is universe infinite? (c) Why is the night sky dark? (e) Why is the universe expanding? 38. The particles which produce meteor showers mostly come from: (a) impacts of asteroids with the moon (b) collisions of asteroids with each other (c) debri from comets (d) Jupiter 39. The objects which produce meteorites come from: (a) mostly asteroids, but sometimes comets (b) mostly comets, but sometimes asteroids (c) debri from comets (d) collisions of ring particles from Saturn 40. Long period comets come from and short period comets come from (a) Oort cloud and Kuiper Belt (b) Kuiper Belt and Oort Cloud (c) Venus and Mars (d) none of the above Have a great summer! 7