Astronomy 1 Final Sample NAME:_____________ Part I: Multiple Choice (2 points. ea.) Choose the best answer for each question Questions 1-5 refer to the schematic model of the Milky Way Galaxy shown at right ___1. Globular clusters and stars in the galactic halo A ___2. The Sun’s location in the galaxy ___3. The disk A ___4. The Galactic bulge B C E ___5. The Galactic nucleus D ___6. Why are HII regions red in color? (A) They contain considerable quantities of dust (B) They emit hydrogen emission lines (C) They are moving away from us at high speed (D) Twenty-one cm photons are red in color ___7. We cannot see the other side of the galaxy primarily because our view is blocked by (A) too many stars. (B) glowing interstellar gas. (C) planetary nebulae and supernova remnants. (D) interstellar dust. ___8. What effect do interstellar dust particles have on the appearance of a distant star? (A) They make it look bluer and brighter. (B) They make it look bluer and dimmer. (C) They make it look redder and brighter. (D) They make it look redder and dimmer. ___9.The Milky Way is (A) a gas cloud in the solar system. (B) a gas cloud in the galaxy of which the sun is a member. (C) the galaxy of which the sun is a member. (D) a nearby galaxy. 1/13 Astronomy 1 Final Sample ___10. What did Harlow Shapley discover about globular clusters that allowed him to determine the size of the galaxy and the Sun’s location within it? (A) The clusters are confined to a thin plane. (B) The clusters are all located at the same distance from the Sun. (C) The center of the distribution of clusters is far from the Sun. (D) All of the clusters are located in a region a few parsecs across. ___11. The mass of the galaxy has been found by (A) Counting the stars it contains (B) Determining its gravitational force on nearby galaxies (C) Estimating the number of interstellar clouds it contains (D) Applying Kepler's laws to the Sun's orbit about the galaxy ___12. Where are stars being formed in the galaxy? (A) In the spiral arms. (B) In globular clusters. (C) In the nucleus. (D) In the halo. ___13. Which of the following is a true statement about the spiral arms of our galaxy? (A) Spiral arms are the crests of density waves. (B) Star formation occurs in the spiral arms. (C) They contain H II powered by the ultraviolet light from hot O and B stars (D) all of the above ___14. Hubble's original classification of galaxies was based on (A) the visual appearance of the galaxies. (B) the physical shape and size of the galaxies. (C) the dominant spectral class of stars. (D) a completely random selection. ___15. Elliptical galaxies are yellowish/reddish in color because they (A) Shine due to synchrotron radiation (B) Contain relatively few young, hot stars (C) Are moving away faster than other galaxies (D) Are surrounded by intergalactic dust clouds ___16. Which of the following is not one of the main categories for the classification of galaxies? (A) irregular (B) elliptical (C) spiral (D) orthogonal 2/13 Astronomy 1 Final Sample ___17.The masses of galaxies are often determined by (A) Determining their star formation rates. (B) Counting their stars. (C) Measuring their tidal forces on the Milky Way. (D) Measuring their rotation curves. ___18. What evidence do we have that galaxies have extended haloes of dark matter? (A) Orbital speed in the rotation curve doesn’t fall off for the outer parts of galaxies. (B) The outer parts of galaxies are intense infrared sources. (C) Light from background galaxies is blocked by the dark matter. (D) The orbits of distant globular clusters are distorted by the dark matter ___19. How was Hubble able to determine the distances of nearby galaxies? (A) by observing Cepheid variables in them (B) by measuring the typical angular separations of stars in them (C) by using radar (D) by measuring trigonometric parallaxes ___20. Hubble’s relationship between the distance to a galaxy and its speed of recession is interpreted as evidence for (A) the expansion of the universe. (B) galaxies being outside the Milky Way. (C) the evolution of galaxies. (D) the Doppler effect. ___21. Which of the following is true of Seyfert galaxies? (A) They have no spiral arms (B) They have unusually bright nuclei (C) They are a form of elliptical galaxy (D) They are all found in the Local Group of galaxies ___22. For a typical luminous radio galaxy, the radio emission comes primarily from (A) the central few hundred parsecs of the galaxy (B) large lobes on opposite sides of the visible galaxy. (C) a large halo with a radius of about ten kiloparsecs. (D) the disk, where most of the stars are concentrated ___23. Some quasars vary in brightness in only a few days. What does this tell us about the quasars? (A) They have large magnetic fields (B) They are quite small (C) They must be highly luminous (D) They cannot emit radio waves ___24. Since quasars are thought to be at cosmological distances, we see them as they were when (A) the universe was much older than it is today (B) the universe was relatively young (C) the universe was contracting (D) the universe was much larger than it is today 3/13 Astronomy 1 Final Sample ___25. According to current theories, the energy source of radio galaxies and quasars is (A) a one thousand solar mass pulsar in each of two radio lobes. (B) a one hundred million solar mass black hole accreting matter at the center of the object. (C) the conversion of hydrogen to helium via nuclear reactions. (D) gravitational contraction of massive stars near the spiral arms. ___26. The maximum luminosity that the nucleus of a galaxy could have without pushing away surrounding matter is called the (A) spiral density wave. (B) event horizon. (C) mass-luminosity relationship. (D) Eddington luminosity. ___27. The brightest quasars are (A) about 1% as bright as the Milky Way (B) as bright as the Milky Way (C) as bright as 10,000 Milky Way galaxies (D) about as bright as the Sun ___28 Quasars all have great distances. Why are there no nearby quasars? (A) No quasars have existed in the recent past. (B) Quasars avoid spiral galaxies. (C) Quasars are found only in clusters of galaxies. (D) If quasars are too close to us, they look like pulsars. ___29. Which of the following statements best describes the distribution of galaxies in the universe? (A) the galaxies lie on sheets and chains surrounding empty regions (B) the galaxies are distributed uniformly in space (C) there are a few large clusters of galaxies with nothing in between (D) there are many clusters near us in space, but nothing beyond ___30. The Local Group is: (A) a group of about 30-50 galaxies containing the Milky Way galaxy. (B) the local group of Population II stars in the solar neighborhood. (C) a large supercluster of galaxies centered on the Milky Way. (D) all stars within 10 pc. of the sun ___31. The richness of a cluster of a galaxies is a measure of (A) how many galaxies it contains. (B) its age. (C) its distance. (D) its redshift ___32. A cluster of galaxies is consider rich if (A) it contains more helium than hydrogen (B) it has a large number of galaxies (C) a large fraction of its mass consists of hot intergalactic gas (D) it contains numerous quasars 4/13 Astronomy 1 Final Sample ___33. The model of cluster formation in which clusters form first which then fragment to form galaxies is called the (B) implosion model. (C) hierarchical clustering model. (A) pancake model. (D) top-down model. ___34. The point in space towards which nearby clusters of galaxies appear to be moving is referred to as (A) “The Great Attractor”. (B ) “The Whole Shebang”. (C) “LGM”. (D) “The Big Crunch”. ___35.In which part of the sky is the cosmic background radiation brightest? (A) equally bright in all parts of the sky. (B) toward the Virgo cluster (C) toward the center of the universe (D) toward the spot where the Big Bang took place ___36. Which of the following is not true of the cosmic background radiation? (A) it is nearly equally bright in all directions (B) it came from glowing gas at the time the universe became transparent. (C) it is currently brightest in the radio (microwave) part of the spectrum (D) it is starlight ___37. Which of the following is NOT an implication of Hubble's law? (A) the universe is expanding. (B) we are in the center of the universe. (C) the universe had a beginning. (D) the universe was once denser than it now is ___38. The expansion age of the universe is about (A) 12 to 14 million years. (B) 12 to 14 billion years. (C) 120 to 140 billion years. (D) 1200 to 1400 billion years. ___39. What was the universe made of one hour after it began to expand? (A) hydrogen and helium (B) carbon and oxygen (C) iron and nickel (D) potassium and carbon 5/13 Astronomy 1 Final Sample ___40. The conversion of hydrogen into helium began about 2 minutes after the beginning of the expansion of the universe. Why was there no helium in the universe during the first 2 minutes? (A) There was no matter in the universe during the first 2 minutes.