Secular deceleration - Secular deceleration

...Other factors that affect the speed of rotation include the rise and fall of ice sheets in the Antarctic, major earthquakes, crustal movements, and electromagnetic coupling between the Earth's core and mantle. The tidal friction between the ocean water and the ocean floor puts the brakes on the Earth's rotation, gradually slowing it down. This phenomenon is called secular deceleration, and the length of a day increases by about 0.014 seconds every 100 years. Meanwhile, the Moon's orbital speed is also slowed down by the gravitational force of the ocean water, and according to Kepler's third law, the distance between the Earth and the Moon increases at a rate of 3.3 cm per year.

*Some of the terminology used to refer to "secular deceleration" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…このほか南極の氷床の消長，大地震，地殻変動，地球の核とマントルとの間の電磁気的カップリングによっても自転速度に変化が生じる。海水と海底との間に生じる潮汐摩擦によって自転にブレーキがかかり，しだいに自転速度が減る現象を永年減速といい，1日の長さが100年間に約0.014秒ずつ長くなる。一方，月の公転速度も海水の引力によって減速され，ケプラーの第3法則に従って，地球と月との距離は3.3cm/年の割合で大きくなる。…

※「永年減速」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報