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Nutation
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Wobbling superimposed on precession.
Small nodding oscillations superimposed on precession, damped by friction. It occurs when the spin is initially not exactly at steady precession.
Earth's axis shows nutation of 9 arcseconds with an 18.6-year period.
Seen in tops that wobble.
In more detail
Nutation is a small wobble or nodding of a spinning body's axis, superimposed on its precession. It occurs when the spin axis is not aligned with the angular momentum.
Real-world uses
- The Earth's axis nutates slightly, with a period of about 18.6 years.
- Spinning top and gyroscope designs must account for nutation.
- A gyroscope in a ship or aircraft wobbles slightly as it precesses, a small motion called nutation.
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Frequently asked questions
Does nutation affect the Earth's climate?
It causes small changes in the orientation of the axis, though its effect on climate is small.
Why does a top wobble?
Nutation is the wobble that appears when the initial conditions are not perfectly steady.
Is nutation large in most devices?
It is usually small and is damped by friction, but it can matter in precise navigation instruments.
Related topics in Rotational Motion
Spinning skater and diver · Collisions in rotation · Precession of a gyroscope · Rotation of the Earth · Tops and bicycles · Rotating frames