Flashcards on Mastering Astronomy Chapter 1
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If we represent the solar system on a scale that allows us to walk from the Sun to Pluto in a few minutes, then:
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the planets would all be marble size or smaller and the nearest stars would be thousands of miles away.
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What do astronomers mean by the Big Bang?
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the event that marked the beginning of the expansion of the universe
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An astronomical unit is
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Earth's average distance from the Sun
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Put the following into perspective: the size of our solar system; the distance to nearby stars; the size of the Milky Way Galaxy; the size of the observable universe. Rank from largest to smallest. To rank items as equivalent, overlap them.
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The observable universe, The Milky Way Galaxy, Distances to nearby stars, solar system
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Our solar system consists of
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the sun and all the objects that orbit it
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On a scale where the Sun is about the size of a grapefruit and the Earth is about 15 meters away, how far away are the nearest stars besides the Sun?
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about the distance across the United States
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A television advertisement claiming that a product is light-years ahead of its time does not make sense because
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it uses \"light-years\" to talk about time, but a light-year is a unit of distance
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The total number of stars in the observable universe is roughly equivalent to
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the number of grains of sand on all the beaches on Earth.
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Which of the following has your \"cosmic address\" in the correct order?
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You, Earth, solar system, Milky Way Galaxy, Local Group, Local Supercluster, universe
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When we look at an object that is 1,000 light-years away we see it _
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as it was 1,000 years ago
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Suppose we look at two distant galaxies: Galaxy 1 is twice as far away as Galaxy 2. In that case
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we are seeing Galaxy 1 as it looked at an earlier time in the history of the universe than Galaxy 2
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Could we see a galaxy that is 20 billion light-years away? (Assume that we mean a \"lookback time\" of 20 billion years.)
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No, because it would be beyond the bounds of our observable universe.
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Suppose we make a scale model of our solar system, with the Sun the size of a grapefruit. Which of the following best describes what the planets would look like?
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The planets are all much smaller than the Sun. Four planets are within about 20 meters of the Sun, while the rest planets are spread much farther apart.
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If you could count stars at a rate of about one per second, how long would it take to count all the stars in the Milky Way Galaxy?
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Several thousand years
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The total number of stars in the observable universe is about
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the same as the number of grains of sand on all the beaches on Earth
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Using the ideas discussed in your textbook, in what sense are we \"star stuff\"?
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Nearly every atom from which we are made was once inside of a star.
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How are galaxies important to our existence?
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Galaxies recycle material from one generation of stars to the next, and without this recycling we could not exist.
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If we imagine the history of the universe compressed into one year, dinosaurs became extinct
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yesterday morning
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Relative to the age of the universe, how old is our solar system?
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It is about one-third the age of the universe.
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How do the speeds at which we are moving with Earth's rotation and orbit compare to the speeds of more familiar objects?
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Earth's rotation carries most people around the axis faster than a commercial jet travels, and Earth's orbit carries us around the Sun faster than the Space Shuttle orbits Earth.
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Why do the patterns of the stars in our sky look the same from year to year?
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Because the stars in the constellations are so far away.
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Where is our solar system located within the Milky Way Galaxy?
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Roughly halfway between the center and the edge of the visible disk of the galaxy
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Astronomers infer that the universe is expanding because distant galaxies all appear to
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be moving away from us, with more distant ones moving faster
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Which statement about motion in the universe is not true?
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The mysterious dark matter is the fastest-moving material in the universe.
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The star Betelgeuse is about 600 light-years away. If it explodes tonight,
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we won't know about it until 600 years from now.
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The fact that nearly all galaxies are moving away from us, with more distant ones moving faster, helped us to conclude that:
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The universe is expanding
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What do we mean when we say that the universe is expanding?
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Average distances between galaxies are increasing with time.
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If the 14 billion year history of the universe were compressed to one year, and \"now\" is exactly midnight December 31, approximately how long ago were your grandparents born?
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0.15 second ago
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What is the \"Raisin Cake model\" intended to explain?
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that every raisin in a raisin cake moves farther away from every other raisin: there is no special central raisin (and no special central galaxy)
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Which of the following correctly lists our \"cosmic address\" from small to large?
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Earth, solar system, Milky Way Galaxy, Local Group, Local Supercluster, universe
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The Earth rotates one a _ on its acis and orbits the Sun once each _ The eliptic plane is the plane defines by _ 's orbit around _. Axis tolt of a planet is the amount that _ is tipped relative to a line perpendicular to the ecliptic plane.
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day, year, Earth, the Sun, its axis
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Which of the following best describes what we mean by the universe?
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the sum total of all matter and energy
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The term observable universe refers to
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that portion of the universe that we can see in principle, given the current age of the universe
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Could we see a galaxy that is 50 billion light-years away?
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No, because it would be beyond the bounds of our observable universe.
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The age of our solar system is about:
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one-third of the age of the universe.
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Which of the following is a general difference between a planet and a star?
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Stars glow in infrared and visible light, while planets glow only in the infrared.
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When we say the universe is expanding, we mean that:
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The average distance between galaxies is growing with time
