The eccentricity of a planet's orbit describes:
A) the tilt of the planet's spin axis with respect to its orbital plane.
B) its shape compared with that of a circle.
C) its motion at any specific point in its orbit as seen from Earth, that is, whether direct, retrograde, or stationary.
D) its tilt with respect to the plane of Earth's orbit (the ecliptic plane).

Question

Quizplus · Accepted Answer

Eccentricity describes the shape of a planet's orbit and how far it deviates from a perfect circle. It is calculated as the ratio of the distance between the foci of the ellipse that represents the planet's orbit to the length of the major axis of the ellipse. A perfect circle has an eccentricity of 0, while a highly elongated and eccentric orbit has an eccentricity close to 1.

The Eccentricity of a Planet's Orbit Describes