The tropical year is shorter than the sidereal year because Earth's
A) orbit is an ellipse rather than a true circle.
B) axis precesses westward.
C) orbital speed is not constant.
D) axis is tilted by 23.5°.

Question

Quizplus · Accepted Answer

The tropical year is shorter than the sidereal year primarily because of the precession of Earth's axis, which causes the positions of the equinoxes to shift slightly each year. This means the time it takes for the Sun to return to the same position in the cycle of seasons (tropical year) is slightly less than the time it takes to return to the same position relative to the stars (sidereal year).

The Tropical Year Is Shorter Than the Sidereal Year Because