In appearance, what immediately distinguishes Saturn from all the other planets?
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Its large ring system
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Why does the appearance of Saturn's rings change over time as seen from Earth?
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The rings lie in the planet's equatorial plane, which is tilted with respect to the ecliptic.
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Why is Saturn's atmosphere almost three times thicker than Jupiter's?
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Saturn is less massive than Jupiter; its gravity is weaker.
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What substance is underabundant (compared to Jupiter) in the atmosphere of Saturn?
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Helium
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What two factors enable Saturn to retain its primordial hydrogen?
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The planet's large mass (resulting in a high escape speed) and low temperature
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Why is Saturn's atmosphere less varied in color and appearance than Jupiter's atmosphere?
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Saturn's top clouds are thicker, with few holes and gaps, and they obscure the deeper layers.
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The surface temperature of Saturn, though cold, is much higher than would be expected from the amount of solar energy it receives. Which of the following factors is thought to be the primary cause of this higher temperature?
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Continued gravitational settling of liquid helium
*Because of Saturn's low internal temperature, the liquid helium in its interior condenses to form a continuous helium precipitation that settles toward the planet's core, releasing energy.
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Why does Saturn have only about half as much helium as a fraction of its total atmospheric composition as do Jupiter, Uranus, and Neptune?
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Helium may have liquefied and precipitated down into the interior of Saturn, reducing the overall proportion of helium in the atmosphere.
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The Roche limit is that distance from a planet where ________.
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tidal forces are equal to internal forces
*The Roche limit is the tidal stability limit, the critical distance inside of which the moon is destroyed. Only smaller ring particles are found within the Roche limit; larger bodies would be broken up by tidal stress.
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Saturn's rings are composed of mainly which of the following?
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Water ice
*Saturn's rings are composed of many tiny particles, with water ice being the main constituent.
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How is Titan's surface tempurature compared to Earth's
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Titan's surface temperature is 94 K, much cooler than Earth's.
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Mimas is a moon of Saturn with which of the following characteristics?
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A very large impact crater and a role in maintaining one of Saturn's rings
*The impact that formed this large crater, called Herschel, may have nearly shattered Mimas.
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Saturn's moon Iapetus has a surface that shows which of the following features?
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Two-tone markings
*The dark leading face reflects only about 3 percent of the sunlight that reaches it and contrasts strongly with the icy trailing face, which reflects about 50 percent.
