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1 | |
Galaxies come in three main flavors, which are |
| | A) | barred spiral, irregular, and Seyfert |
| | B) | Seyfert, radio, and quasar |
| | C) | spiral, elliptical, and irregular |
| | D) | old, young, and intermediate |
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2 | |
Which of the following is not a property of elliptical galaxies? |
| | A) | They contain mostly old (Pop II ) stars. |
| | B) | They have little dust or gas. |
| | C) | They have prominent spiral arms. |
| | D) | Stars are distributed smoothly throughout their volume. |
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3 | |
When two galaxies collide, what happens to their stars? |
| | A) | About 30% of them collide and become black holes. |
| | B) | About 50% of them become binary stars. |
| | C) | The evolution of all the stars in the larger galaxy is accelerated. |
| | D) | Nothing happens to them, except that their orbits may change. |
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4 | |
Why are galaxy collisions of interest? |
| | A) | Collisions and mergers play an important role in shaping galaxies. |
| | B) | Collisions have a strong effect on the evolution of stars. |
| | C) | Collisions are extremely rare. |
| | D) | Both b and c. |
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5 | |
A galaxy has a recession velocity of 10,000 km/sec. If the Hubble constant is 65 km/sec per megaparsec, roughly how far away is the galaxy? (Hint: see Figure 16.15) |
| | A) | 10 megaparsecs. |
| | B) | 25 megaparsecs. |
| | C) | 60 megaparsecs. |
| | D) | 130 megaparsecs. |
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6 | |
In part, astronomers believe that dark matter exists because |
| | A) | they can detect it with radio telescopes. |
| | B) | the galaxies in clusters move faster than expected on the basis of the material visible in them. |
| | C) | it is the only way to explain the black holes in active galaxies. |
| | D) | they have detected neutrinos from unseen sources. |
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7 | |
Name the three main types of active galaxies. |
| | A) | barred spiral, irregular, and Seyfert |
| | B) | Seyfert, radio, and quasar |
| | C) | spiral, elliptical, and irregular |
| | D) | old, young, and intermediate |
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8 | |
Where does most of the radio emission in a radio galaxy come from? |
| | A) | The center |
| | B) | The spiral arms. |
| | C) | Outside the galaxy in radio lobes. |
| | D) | A thin shell surrounding the galaxy. |
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9 | |
Which of the following is a property of Seyfert galaxies? |
| | A) | Their nuclei have abnormally low luminosities. |
| | B) | They contain no gas clouds. |
| | C) | The radiation from their cores fluctuates rapidly. |
| | D) | Most are elliptical galaxies. |
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10 | |
Why do we think that quasars are extremely distant? |
| | A) | Their light varies rapidly. |
| | B) | Their spectra show immense redshifts. |
| | C) | They are very bright. |
| | D) | They are very faint. |
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11 | |
Why do we think that active galaxies have small core regions? |
| | A) | We can measure their size on the sky, which means they are small and near. |
| | B) | They emit radio waves that larger objects cannot do. |
| | C) | Their light varies rapidly, implying small radius. |
| | D) | They are very far away, and thus are younger and less expanded. |
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12 | |
What could make active galaxies so energetic? |
| | A) | An immense black hole. |
| | B) | Intense magnetic fields |
| | C) | A supernova explosion. |
| | D) | None of the above. |
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13 | |
What is a gravitational lens? |
| | A) | A heavy contact lens. |
| | B) | A massive object that bends the space around it, causing light to bend. |
| | C) | An extremely massive refractor telescope. |
| | D) | A lens that is affected by gravity. |
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14 | |
Our Milky Way is part of _________ which has about ____ member galaxies. |
| | A) | The Coma cluster / 500. |
| | B) | The Pleiades / 3 other. |
| | C) | The Local Group / 30. |
| | D) | The Beehive Association / 100. |
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15 | |
What is a void? |
| | A) | A region in the Universe where there are almost no galaxies. |
| | B) | A part of the sky where no galaxies are visible to us because of obscuring dust in the Milky Way. |
| | C) | A part of the sky that astronomers cannot observe due to bright emission from interstellar dust. |
| | D) | The region of the Solar System where it is too dangerous to send spacecraft. |
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2002 McGraw-Hill Higher Education