A comet is observed to return to the vicinity of the Sun on a long elliptical orbit with a period of 31.7 years.What is the semimajor axis of the orbit?
A) 31.7 AU
B) 178.5 AU
C) 10 AU
D) 1000 AU

Question

Quizplus · Accepted Answer

The semimajor axis (a) of a comet's orbit can be found using Kepler's Third Law, which states that the square of the orbital period (P) is proportional to the cube of the semimajor axis (a): P^2 = a^3. For a period of 31.7 years, solving for a gives approximately 10 AU.

A Comet Is Observed to Return to the Vicinity of the Sun