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CAST — California Science Test The Moon and Mercury — practice questions

Explore 15 free The Moon and Mercury questions in CAST — California Science Test Science. Open each question or exercise to read its content, reference answers and available explanation.

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The Moon and Mercury questions and exercises with answers

Showing questions 1–15 of 15.

The Moon holds no atmosphere today. What is the basic reason?Read the answer and worked solution →The dark, smooth patches early observers called seas on the Moon are made of what?Read the answer and worked solution →Nearly every impact crater is circular rather than oval. Why does that happen?Read the answer and worked solution →Mercury takes how long to travel once around the Sun?Read the answer and worked solution →Compared with Earth, the Moon is strongly short of which materials?Read the answer and worked solution →The bright, heavily cratered lunar highlands make up what share of the Moon's crust?Read the answer and worked solution →A crater is usually how much wider than the object that dug it out?Read the answer and worked solution →In the giant impact idea for the Moon's birth, how big was the body that struck Earth?Read the answer and worked solution →Mercury's high density points to a core that holds what share of the planet's mass?Read the answer and worked solution →The idea that Earth simply captured a passing Moon runs into which specific problem?Read the answer and worked solution →Mercury spins once in 59 Earth days and circles the Sun in 88. How long does the Sun take to return to the same spot in its sky?Read the answer and worked solution →Long cliffs on Mercury cut straight across older craters. What does that tell us?Read the answer and worked solution →Drop each trait onto the right worldRead the answer and worked solution →Knock out the cratering mythsRead the answer and worked solution →Place each mission on the years lineRead the answer and worked solution →

Worked practice questions

The Moon holds no atmosphere today. What is the basic reason?

  1. Its surface gravity is too low
  2. Its surface is far too cold
  3. Its orbit is far too wide
  4. Its rotation is far too slow
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Correct answer: A. Its surface gravity is too low

1. Gas molecules move fast enough to leak away from a small world. 2. The Moon's surface gravity is about one sixth of Earth's. 3. That pull is too weak to hold gas, so any atmosphere escapes or freezes onto the surface. _Source: OpenStax Astronomy (CC BY 4.0), section 9.1 General Properties of the Moon_

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The dark, smooth patches early observers called seas on the Moon are made of what?

  1. Granite from old crust
  2. Basalt from volcanic lava
  3. Ice left by old comets
  4. Dust blown by the wind
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Correct answer: B. Basalt from volcanic lava

1. The dark patches were named maria, the Latin word for seas, by early observers. 2. They are not water but flat plains of dark basalt. 3. That basalt was erupted as lava that flooded huge impact basins long ago. _Source: OpenStax Astronomy (CC BY 4.0), section 9.2 The Lunar Surface_

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Nearly every impact crater is circular rather than oval. Why does that happen?

  1. The rock melts and then flows
  2. The world spins under the hit
  3. The impact sets off an explosion
  4. The rim slumps into a ring
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Correct answer: C. The impact sets off an explosion

1. An incoming body arrives at least as fast as the escape speed of the world it hits. 2. At that speed the energy of motion turns into a violent explosion on contact. 3. An explosion digs outward evenly in every direction, so the pit comes out round. _Source: OpenStax Astronomy (CC BY 4.0), section 9.3 Impact Craters_

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