How long will it take for precession to move Earth's spin axis to a position perpendicular to the ecliptic plane?
A) no time at all because the axis is in this position now
B) a very long or even infinite time because it is very unlikely to happen
C) 13,000 years
D) 26,000 years

Question

Quizplus · Accepted Answer

The Earth's spin axis is currently tilted at about 23.5 degrees to the plane of its orbit around the Sun, and precession causes this axis to trace out a cone over a period of approximately 26,000 years. However, precession alone will not move the Earth's spin axis to a position perpendicular to the ecliptic plane; it merely alters the orientation of the axis within its current tilt. Therefore, it is very unlikely or would take a very long or even infinite time for the axis to become perpendicular solely due to precession.

How Long Will It Take for Precession to Move Earth's