Astronomy 123
Sample Exam Questions. A quasar with a red shift of 2 would be at which of the following look-back times? a. 4 years b. 1,000 years c. 10,000,000 years answer. about 10,000,000,000 years . The spectrum of light coming from normal galaxies is characterized by a. enormous amounts of synchrotron radiation answer. the sum of many blackbody spectra c. large radio emission d. dominance in the infrared part of the electromagnetic spectrum . A rare form of galaxy is a. an irregular galaxy b. an elliptical galaxy c. a spiral galaxy answer. an active galaxy . How do we know that about 90% of the matter in galaxies has not been observed? answer. From the galactic rotation curves b. From an extrapolation of the rate of discovery of matter c. From the high luminosity of the galactic halo d. All of the above . When the globular clusters were formed, the Milky Way was answer. a large sphere of at least 100,000 light years diameter b. a disk of molecular clouds without spiral arms c. a disk of molecular clouds with spiral arms d. a disk of Population I stars . The Very Large Array in New Mexico a. combines many mirror segments into one large telescope b. detects the highest energy x-rays c. produces high resolution images with infrared sensors answer. detects radio emissions e. all of the above . What is a gravitational lens? answer. light is bent by matter b. matter pushing on antimatter c. antimatter changing the color of light d. all of the above . The number of stars in the Milky Way Galaxy is thought to be nearest a. 106 b. 108 c. 109 answer. 1011 e. 1014 . Which of the following is NOT an active galaxy a. M87 b. Centaurus A c. Cygnus A answer. M31 . The variations in a Seyfert galaxy's luminosity over a year or so shows its region of emission is answer. not very large b. moving toward us at great speed c. moving away from us at great speed d. a and c . Variable stars are useful as standard candles because of the close relationship between answer. period of pulsation and luminosity b. period of pulsation and apparent brightness c. luminosity and apparent brightness d. all of the above. . What was the subject of the famous Shapley-Curtis debate? a. The origin of galaxies b. The value of Hubble's constant c. Dark matter answer. The nature and distance of spiral nebulae . The first supernova visible to the naked eye on Earth since the invention of the telescope appeared in 1987. Where did it appear? a. in Sagittarius answer. in the Large Magellanic Cloud c. in M87 d. in the Coma Cluster . The largest objects seen in the universe are answer. radio galaxies b. irregular galaxies c. supernovae d. black holes . In a lobe radio galaxy, the radio emission primarily comes from a. the nucleus of the galaxy b. the galaxy's globular clusters answer. enormous extensions of the galaxy that dwarf the optical galaxy d. a mysterious parallel galaxy, usually a million light-years from the optical galaxy .. The Cosmological Assumptions include all of the following except a. The cosmos is homogeneous b. The universe is isotropic answer. The universe is infinite d. The universality of physical laws . Which of the following futures is not possible for a Big Bang universe? answer. Galaxy formation continuing forever b. Expansion forever c. Eventual collapse d. None of the above . The cosmic microwave background radiation we observe on Earth now answer. has traveled for more than ten billion years b. has been tremendously blue-shifted c. was created by the dense structure of quasars d. comes from the center of the universe . Images of young, background galaxies, warped by the gravitational field of a foreground galaxy cluster are a. radio galaxies b. BL Lac Objects answer. blue arcs d. bridge to the past . What causes the small asymmetry in the cosmic microwave background? a. black holes b. the Sun's spots c. Jupiter answer. Earth's motion through space . What is the approximate fraction of the critical density represented by normal matter? answer. 0.05 b. 0.20 c. 0.35 d. 0.90 . What might arise from vacuum energy? a. Supernovae answer. A cosmological constant c. A universe that gets hotter with time d. None of the above . The first evidence of dark energy came from answer. Measurements of distant supernovae b. Nuclear power plants c. Extraterrestrial intelligence d. Supermassive black holes . Dark energy is responsible for a. The Big Bang answer. An accelerating expansion of the universe c. Supermassive black holes d. All of the above . The bullet cluster is an example of a. a local galaxy cluster b. a super-rich galaxy cluster answer. the collision of two galaxy clusters d. a cluster which is moving at nearly the speed of light . Assumed property of the universe which says the number of galaxies in a volume of space is the same no matter where that volume is a. closed b. open c. isotropic answer. homogeneous . Assumed property of the universe which says it is the same in all directions a. closed b. open answer. isotropic d. homogeneous . The distance from Earth to the Great Wall is a. about 100 pc b. about 1,000 pc c. about 1,000,000 pc answer. about 100,000,000 pc .. Regions of the universe now separated by very large distances appeared with the same temperature in the early universe. This is known as a. nucleosynthesis b. universal expansion c. the flatness problem answer. the horizon problem . If the early universe differed slightly from the critical density it would now differ greatly. This is known as a. nucleosynthesis b. universal expansion answer. the flatness problem d. the horizon problem . The radiation era ended and the matter era began about ________ after the Big Bang started. a. 10-35 seconds b. 20 minutes answer. 50,000 years d. 2 billion years . Most of the fusion of the nuclear epoch occurred during the first ____________ of the Big Bang. a. 10-35 seconds answer. 20 minutes c. 2 million years d. 2 billion years . Inflation occurred within __________ of the Big Bang. answer. 10-35 seconds b. 20 minutes c. 2 million years d. 2 billion years . The temperature fluctuations on the microwave background are found to be a. about 0.1 K b. a few percent answer. a few parts per 100,000 d. no fluctuations have yet been found . Pair production can create which of the following pairs a. a G-type star and a neutron star b. a proton and a neutron answer. an electron and a positron d. all of the above . Which of the following problems does Inflation NOT solve? a. The Horizon Problem answer. The Collider Problem c. The Flatness Problem d. The Monopole Problem