The distance between a planet's aphelion point and its perihelion point is
A) the semimajor axis of its ellipse.
B) twice the semimajor axis of its ellipse.
C) the eccentricity of its ellipse.
D) twice the eccentricity of its ellipse.

Question

Quizplus · Accepted Answer

The distance between a planet's aphelion point (farthest point from the Sun in its orbit) and its perihelion point (closest point to the Sun) is twice the semimajor axis of its elliptical orbit. This is because the semimajor axis is the average distance from the center of the ellipse to a point on its perimeter, effectively half the distance from perihelion to aphelion.

The Distance Between a Planet's Aphelion Point and Its Perihelion