The Gyroscope

A rigid body which spins quickly, whose axis can change orientation in the space. This characteristic is typical of planets, bullets, screws of the ships etc.

The possibility for the axis to assume the favourite position is due to an appropriate assembling.

Therefore the gyroscope has three degrees of freedom and can rotate as he prefers around the point of suspension. The Earth's axis undergoes precession in a time cycle of 25 000 years.