Astronomy – Space Questions – Flashcards
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The two most important processes in heating the interiors of the terrestrial worlds are __________.
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(1) heat deposited by the process of formation; (2) heat released by radioactive decay
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Earth has been gradually warming over the past few decades. Based on a great deal of evidence, scientists believe that this warming is caused by _____.
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human activities that are increasing the concentration of greenhouse gases in Earth's atmosphere
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The terrestrial planets are made almost entirely of elements heavier than hydrogen and helium. According to modern science, where did these elements come from?
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They were produced by stars that lived and died before our solar system was born.
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Which of the following statements about asteroids, Kuiper belt objects, and Oort cloud objects is true?
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Objects in the asteroid belt and Kuiper belt orbit the Sun in nearly the same plane as the planets, but objects in the Oort cloud do not.
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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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What atmospheric constituent is responsible for the blue color of Uranus and Neptune?
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methane
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The processes responsible for virtually all surface geology are _________.
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impact cratering, volcanisms, tectonics, and erosion
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Which of the following is a general characteristic of the four jovian planets in our solar system?
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They are lower in average density than are the terrestrial planets.
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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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typical meteor is created by a particle about the size of a _________.
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pea
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According to current evidence, Pluto is best explained as ______
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a large member of the Kuiper belt
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what is true about comets in our solar system?
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-All comets orbit the sun -All comets are icy in composition. -All comets are leftover planetesimals that originally condensed beyond the frost line in the solar nebula.
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When we say that jovian planets contain significant amounts of hydrogen compounds, we mean
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methane, water, ammonia
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According to our theory of solar system formation, what are asteroids and comets?
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leftover planetesimals that never accreted into planets
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Based on all we know about the terrestrial worlds, what single factor appears to play the most important role in a terrestrial planet's geological destiny?
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its size
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In general, which of the following are affected by a magnetic field?
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charged particles or magnetized materials (such as iron)
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Which statement about Io is true?
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It is the most volcanically active body in our solar system.
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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 of the following best describes the internal layering of Jupiter, from the center outward?
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core of rock, metal, and hydrogen compounds; thick layer of metallic hydrogen; layer of liquid hydrogen; layer of gaseous hydrogen; cloud layer
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Which of the following does NOT provide evidence that Mars once had abundant liquid water on its surface?
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the presence of canali, discovered in the late 1800s by Giovanni Schiaparelli and mapped by Percival Lowell
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According to modern scientific dating techniques, approximately how old is the solar system?
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4.5 billion years
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Overall, Jupiter's composition is most like that of _________.
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the sun
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In essence, the nebular theory holds that _________.
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our solar system formed from the collapse of an interstellar cloud of gas and dust
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Suppose we represent Earth with a basketball. On this scale, most of the air in Earth's atmosphere would fit in a layer that is _________.
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about the thickness of a sheet of paper
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Suppose you view the solar system from high above Earth's North Pole. Which of the following statements about planetary orbits will be true?
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All the planets orbit counterclockwise around the Sun.
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Which moon has a thick atmosphere made mostly of nitrogen?
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titan
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The jovian planets in our solar system are _________.
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Jupiter, Saturn, Uranus, and Neptune
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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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Which of the following types of material can condense into what we call ice at low temperatures?
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hydrogen compounds
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Which of the following is the most basic definition of a greenhouse gas?
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a gas that absorbs infrared light
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The planet in our solar system with the highest average surface temperature is _________.
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Venus
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According to our theory of solar system formation, what three major changes occurred in the solar nebula as it shrank in size?
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It got hotter, its rate of rotation increased, and it flattened into a disk.
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What is the importance of the carbon dioxide (CO2) cycle?
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It regulates the carbon dioxide concentration of our atmosphere, keeping temperatures moderate.
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Suppose you could float in space just a few meters above Saturn's rings. What would you see as you looked down on the rings?
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countless icy particles, ranging in size from dust grains to large boulders
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What is the giant impact hypothesis for the origin of the Moon?
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The Moon formed from material blasted out of Earth's mantle and crust by the impact of a Mars-size object.
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What do we mean by the frost line when we discuss the formation of planets in the solar nebula?
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It is a circle at a particular distance from the Sun, beyond which the temperature was low enough for ice to condense.
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Which moon is considered likely to have a deep, subsurface ocean of liquid water?
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Europa
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Suppose we use a baseball to represent Earth. On this scale, the other terrestrial worlds (Mercury, Venus, the Moon, and Mars) would range in size approximately from that of _________.
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a golf ball to a baseball
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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 of the following statements about the moons of the jovian planets is NOT true?
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Most of the moons are large enough to be spherical in shape, but a few have the more potato-like shapes of asteroids.
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What observational evidence supports the idea that Mercury once shrank by some 20 kilometers in radius?
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the presence of many long, tall cliffs
