In a distant galaxy, a planet orbits its sun at a distance of 1.8 *10¹² m with a period of 10⁸s. A second planet orbits the same sun at a distance of 9 *10¹¹ m. What is the period of the second planet? A) 5 * 10⁷ s B) 2 * 10⁸ s C) 0.35 * 10⁸ s D) 2.8 * 10⁸ s E) 5 * 10⁸ s

Question

Quizplus · Accepted Answer

Using Kepler's third law, the ratio of the squares of the periods of two planets is equal to the ratio of the cubes of their semi-major axes. Solving for the second planet's period gives approximately 0.35 * 10^8 s.

In a Distant Galaxy, a Planet Orbits Its Sun at a Distance