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Ch. 12 Practice Test Questions

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Which of the following statements best describes the size of the largest asteroid, Ceres?
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It is a little less than half the diameter of our Moon.
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If we could put all the asteroids together, their total mass would be ______.
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much less than the mass of any terrestrial planet
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Why didn’t a planet form where the asteroid belt is now located?
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Gravitational tugs from Jupiter prevented material from collecting together to form a planet.
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Gaps in the asteroid belt (often called Kirkwood gaps) are caused by ______.
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orbital resonances with Jupiter
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When you see the bright flash of a meteor, what are you actually seeing?
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the glow from a pea-size particle and the surrounding air as the particle burns up in our atmosphere
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How can we determine the reflectivity of an asteroid?
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By comparing its brightness in visible light to its brightness in infrared light.
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In science fiction movies, spaceships are often shown dodging through large numbers of closely spaced, boulder-size objects. Which of the following real things in our solar system would look most like such science fiction dangers?
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the rings of Saturn
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Suppose you find a meteorite made almost entirely of metal. According to current science, which of the following statements must be true?
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Your meteorite is a fragment from the core of a large asteroid that shattered in a collision.
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Which of the following objects are probably not located in the same region of the solar system in which they originally formed?
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Oort cloud comets
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Suppose there were no solar wind. How would the appearance of a comet in our inner solar system be different?
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It would have only one tail instead of two.
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Suppose we discover a new comet on an orbit that brings it closer to the Sun than Mercury every 125 years. What can we conclude?
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It has been on its current orbit for only a very short time compared to the age of our solar system.
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When we see a meteor shower, it means that _________.
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Earth is crossing the orbit of a comet
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Which of the following is not a piece of evidence supporting the idea that an impact caused the mass extinction that occurred 65 million years ago?
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Fossilized dinosaur bones contain fragments of rock from the impact.
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Suppose that large jovian planets had never formed in our solar system. Which of the following would most likely be true?
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Neither the asteroid belt nor Oort cloud would exist.
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Which of the following statements is not true?
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Objects in the Kuiper belt are made mostly of rock and metal.
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A rock found on Earth that crashed down from space is called ______.
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a meteorite
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The asteroid belt is located ______.
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between the orbits of Mars and Jupiter
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Which statement about asteroids is not true?
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If we could put all the asteroids together, they would make an object about the size of Earth.
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A typical meteor is created by a particle about the size of a _________.
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pea
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What do we mean by a primitive meteorite?
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a meteorite that is essentially unchanged since it first condensed and accreted in the solar nebula some 4.6 billion years ago
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Among discovered meteorites, we have found some with all the following origins except _________.
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being a fragment from Comet Halley
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Which statement is not thought to be true of all comets in our solar system?
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Comets always have tails.
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Which direction do a comet’s dust and plasma tails point?
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generally away from the Sun
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When a comet passes near the Sun, part of it takes on the appearance of a large, bright ball from which the tail extends. This part is called _____.
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the coma
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The total number of comets orbiting the Sun is estimated to be about ______.
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1 trillion
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Halley’s comet is named after the English scientist Edmund Halley (1656–1742) because ______.
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he calculated its orbit and predicted the year in which it would next be seen.
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What was the Shoemaker-Levy 9 impact?
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the 1994 impact of a chain of comet fragments into Jupiter
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What do we mean by a mass extinction?
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the extinction of a large fraction of the world’s plant and animal species in a relatively short period of time
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If the hypothesis tracing the extinction of the dinosaurs to an impact is correct, the dinosaurs died off largely because ______.
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of global climate effects initiated by dust and smoke that entered the atmosphere after the impact