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单词 precession
释义

Definition of precession in English:

precession

noun prɪˈsɛʃ(ə)nprəˈsɛʃən
mass nounPhysics
  • 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.

    Example sentencesExamples
    • 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.
    • Of course, the anomalous precession of Mercury was already known, and general relativity could explain it.
    • The binary's orbital precession, for example, is quite vigorous.
    • As the tailwheel lifts during the takeoff run, gyroscopic precession tries to turn the plane left of centerline.

Derivatives

  • precess

  • verb prɪˈsɛsprəˈsɛs
    [no object]Physics
    • Undergo precession.

      the orbits of Earth and Mars slowly precess around the sun
      Example sentencesExamples
      • 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

  • adjective prɪˈsɛʃnlprəˈsɛʃ(ə)n(ə)l
    Physics
    • 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.
      Example sentencesExamples
      • Due to the precessional movements of both planets the alignment does not repeat precisely.
      • So we are likely to see precessional magnetic switching used for phones and cameras in the near future.
      • 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.
      • In earlier talks I have argued that these cataclysmic floods were, in reality, massive changes in sea level brought about by polar instability, or by precessional wobble in the Earth's mode of spin.

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).

 
 

Definition of precession in US English:

precession

nounprəˈsɛʃənprəˈseSHən
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.

    Example sentencesExamples
    • 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.
    • Einstein's theory predicts that such gyroscopes will undergo geodetic precession merely because space-time is curved in the planet's vicinity.
    • Of course, the anomalous precession of Mercury was already known, and general relativity could explain it.
    • The binary's orbital precession, for example, is quite vigorous.

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).

 
 
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更新时间:2024/12/23 5:09:51