precession
pree se shuhn
- n the motion of a spinning body (as a top) in which it wobbles so that the axis of rotation sweeps out a cone
- n the act of preceding in time or order or rank (as in a ceremony)
- Though this motion, or precession, is barely perceptible, the Martian axis leans in the opposite direction every 25,000 years, or halfway through a complete precessional cycle.
- This precession is caused by the pull of the sun and the moon acting on the slightly nonspherical shape of the earth.
- The needle on one dial, which records the precession (slow conical wobbling) of Earth's axis, will take 26.