nutation

views updated May 21 2018

nutation Oscillating movement (period 18.6 years) superimposed on the steady precessional movement of the Earth's axis so that the precessional path of each celestial pole on the celestial sphere follows an irregular rather than a true circle. It results from the varying gravitational attraction of the Sun and Moon on the Earth. See also precession

World Encyclopedia

nutation

views updated May 08 2018

nutation Irregularities in the orbital motion of the Earth (or other planets) superimposed on the precession of its axis. The dominant nutation of the Earth's axis has an 18.6-year periodicity.

A Dictionary of Earth Sciences AILSA ALLABY and MICHAEL ALLABY

nutation

views updated May 29 2018

nutation nodding XVII; oscillation of the earth's axis XVIII. — L. nūtātiō, -ōn-, f. nūtāre, nūtāt- nod, f. base of -nuere nod; see -ATION.

The Concise Oxford Dictionary of English Etymology T. F. HOAD

nutation

views updated Jun 11 2018

nutation The spiral movement of a plant organ during growth, also known as circumnutation. It is seen in climbing plants and helps the plant find a suitable support to twine around. Examples are the coiling movements of the shoot tips of runner beans and of the tendrils of sweet peas.

A Dictionary of Biology