Chapter 1 of Astronomy – Flashcards
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The fifth planet closest to the Sun is:
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Jupiter
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Match the term to the definition: Asteroid
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A relatively small and rocky object that orbits a star.
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On a scale in which the distance from Earth to the Sun is about 15 meters, the distance from Earth to the Moon is ________.
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small enough to fit within your hand
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Voyager 2 should reach the nearest stars (besides the Sun) in about 500 years.
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False
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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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By studying distant galaxies in the 1920s, Hubble made the following important discovery that led us to conclude that the universe is expanding:
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all galaxies outside the Local Group are moving away from us, and the farther away they are, the faster they're going.
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Match the term to the definition: Nebula
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An interstellar cloud of gas and/or dust.
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The number of stars in the Milky Way Galaxy is approximately ________.
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a few hundred billion
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On the scale of the cosmic calendar, in which the history of the universe is compressed to 1 year, how long has human civilization (i.e., since ancient Egypt) existed?
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a few seconds
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In the grapefruit model of the solar system, it would take a few minutes to walk from the Sun to Pluto.
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True
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How long does it take our solar system to complete one orbit around the Milky Way Galaxy?
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230 million years
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The age of the universe is
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between 10 billion and 16 billion years
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Match the term to the definition: Comet
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A relatively small and icy object that orbits a star.
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One light year is about 10 trillion kilometers.
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True
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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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Which of the following has your "address" in the correct order?
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you, Earth, solar system, Milky Way, Local Group, Local Supercluster
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Using the analogy of a fried egg for the Milky Way galaxy, where is the Sun?
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In the white.
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When did humans learn that the Earth is not the center of the universe?
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within the past 500 years
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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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Which of the following is largest?
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size of a typical galaxy
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Barnard's Star was not discovered until 1916 because
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it is a very dim star and cannot be seen with the naked eye.
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If you represented each star by a grain of sand, how much sand would it take to represent all the stars in the universe?
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more than all the sand on all the beaches on Earth
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On a cosmic calendar, in which the history of the universe is compressed into one year, how long is the average human life span?
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0.2 second
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Which of the following is not a general difference between a planet and a star?
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All planets are made of rock and all stars are made of gas.
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How are galaxies important to our existence?
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Galaxies recycle heavy elements produced in stars into future generations of stars.
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Modern telescopes are capable of seeing bright galaxies up to about
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10 billion light-years away.
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Match the term to the definition: Moon (or satellite)
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An object that orbits a planet.
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The nearest star group to us is
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The Alpha Centauri group of three stars
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Put these objects in the correct order, nearest to farthest from Earth
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The moon, Mars, the Sun, Pluto, the nearest stars
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Give the sequence of planets starting from the sun
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Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, the dwarf planet Pluto
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Which of the following is smallest
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size of a typical planet
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On a 1-to-10-billion scale, about how far is it to the nearest stars
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4,400 kilometers.
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Suppose we imagine the Sun to be about the size of a grapefruit, How far is the nearest star (the stars of Alpha Centauri)?
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2,500 miles
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The diameter of the Sun compared to Earth is larger by
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One hundred times
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The volume of the Sun compared to Earth is larger by
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One million times
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The speed the Earth travels around the Sun is
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60,000 mi/hr
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The Earth is traveling at 840,000 mi/hr toward the constellation
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Leo
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You do not notice that you are spinning on the Earth because
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the atmosphere moves with you
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At the equator we spin
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1,000 miles per hour
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An astronomical unit is
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the distance to the Sun
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On a calm day in Tacoma the atmosphere is moving
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700 miles per hour
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According to current scientific estimates, when did the Big Bang occur?
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about 14 billion years ago
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On the cosmic calender, which compresses the history of the universe into a single year, about when did Earth form?
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in early September
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On the cosmic calender, which compress the history of the universe into a single year, about when did life arise on Earth
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in September
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On the cosmic calender, which compresses the history of the universe into a single year, about when did early humans first walk on earth?
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just a few hours before midnight on December 31
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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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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 a star
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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 the case that_______
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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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Suppose we made a scale model of our solar system, with the Sun the size of a typical grapefruit. Which of the following best describes what the planets would look like?
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The planets are much smaller than the sun. Four planets are within about 20 meters of the sun, while the rest 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 in all the beaches on Earth
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Where is our solar system located within our 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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If we imagine the universe compressed into one year, dinosaurs became extint___________
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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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Astronomers infer that the universe is expanding because distant galaxies all appear to _________.
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Which statement about motion in the universe is not true?
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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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A typical galaxy is a _________.
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collection of a few hundred million to a trillion or more stars, bound together by gravity
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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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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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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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Based on observations of the universal expansion, the age of the universe is about _________.
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14 billion years
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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 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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On a scale in which the distance from Earth to the Sun is about 15 meters, the distance from Earth to the Moon is _________.
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small enough to fit in your hand.
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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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The number of stars in the Milky Way Galaxy is approximately _________
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a few hundred billion
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An astronomical unit (AU) is _________.
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the average distance between Earth and the Sun
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What is the ecliptic plane?
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The plane of Earth's orbit around the Sun
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How long does it take the Earth to complete one orbit around the Sun?
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One year
