Hey, what's your sign? Astrologers believe that we are going through 12 zodiac "ages" that each last 2160yr. This is because the Earth's rotation axis precesses with a 12Ă—2160=26,000yr period. This means that Polaris, the current north star, won't always be the north star! This precession is due to a gravitational torque applied by the sun and moon due to the slight non-spherical shape of the earth. Based on its size, shape, and rotation rate, what is the angular momentum of the earth in kgm2/s? Assume a spherical earth.
What torque, in N m, must be applied by the sun and moon to create the observed precession?​
