🌌 Cosmic Exploration Quiz 3: Gravity, Orbits, and Kepler’s Laws

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🌌 Cosmic Exploration · Quiz 003

Build the orbital-mechanics foundation needed for later eclipses, moons, comets, exoplanets, and spacecraft motion.

Learning goalConnect gravity and Kepler's laws to orbital shape, speed, period, and orbital size.

  • 5 questions
  • Foundation
  • Explanations after finishing
Answered 0/5
FoundationWhich interaction provides the inward acceleration that bends a planet's motion into an orbit around the Sun?
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Think about the force that dominates the motion of planets around the Sun.

UnderstandingAccording to Kepler's first law, which description best represents a planet's orbit around the Sun?
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Recall the geometric shape in Kepler's first law and where the Sun sits within it.

ApplicationTwo small planets orbit the same star. Planet X has a substantially larger orbital semi-major axis than Planet Y. Which should normally have the longer orbital period?
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For planets around the same star, relate orbital size to orbital period.

InterpretationA planet travels on an elliptical orbit. How does its orbital speed near perihelion, where it is closest to the Sun, compare with its speed near aphelion?
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Use Kepler's equal-area law to compare motion near and far from the Sun.

ConnectionFor a small body orbiting the Sun, use the simplified Solar System form of Kepler's third law: P² = a³, where P is measured in Earth years and a in astronomical units. If the body's orbital period is 8 years, approximately what is its semi-major axis?
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Square the period first, then find the value whose cube equals that result.

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