precession
/prɪˈsɛʃ(ə)n
/noun [mass noun] Physics
The slow movement of the axis of a spinning body around another axis due to a torque (such as gravitational influence) acting to change the direction of the first axis. It is seen in the circle slowly traced out by the pole of a spinning gyroscope.Einstein's theory predicts that such gyroscopes will undergo geodetic precession merely because space-time is curved in the planet's vicinity....
- Even Newtonian physics was unable to give a complete explanation of its orbit: the direction of the axis was found to move by rather more than could be explained by precession and the gravitational attraction of the other planets.
- As the tailwheel lifts during the takeoff run, gyroscopic precession tries to turn the plane left of centerline.
Derivatives
precess
- Classical mechanics, in contrast, predicted that the atomic magnets would precess in the field but remain randomly oriented, so the deflections would only broaden (but not split) the beam.
- If we take a single spin 1/2 particle, and put it in a magnetic field, the spin precesses.
- Over just a few months they could actually detect the orbit of the binary system precessing, slowly dragging around.
precessional
- So we are likely to see precessional magnetic switching used for phones and cameras in the near future.
- The rate of change in the direction of the rotational axis is the ratio of torque to angular momentum and so gives a value for the precessional constant.
- That is, if some of the Earth's energy were to be diverted into a slightly larger precessional wobble, the rate of spin should slow down slightly as a consequence.
Origin
Late 16th century (as a term in astronomy, referring to the precession of the equinoxes): from late Latin praecessio(n-), from praecedere 'go before' (see precede).