Open AccessOn the change of kinetical parameters of the Earth during geological times
Author(s) -
Denis C.
Publication year - 1986
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1986.tb06637.x
Subject(s) - secular variation , hydrostatic equilibrium , moment of inertia , moment (physics) , quadrupole , geology , gravitation , geodesy , earth (classical element) , figure of the earth , geophysics , physics , classical mechanics , mathematical physics , quantum mechanics
Summary Using palaeorotation data, the values of important kinetical parameters of the Earth, such as the geometric and dynamic oblatenesses, the gravitational quadrupole moment, the polar moment of inertia, and so on, are computed for different geological epochs. The calculations are based on a formulation of the Clairaut—Laplace—Lyapunov theory expanded to the third order of approximation, and assume that the gross evolution of the Earth can be represented by a succession of states of quasi‐hydrostatic equilibrium. Supposing that no significant growth of the Earth's core has occurred since the Silurian,” the average secular rate of change of the gravitational quadrupole moment, dJ 2 / dt , is about ‐5.9 times 10 −11 per century, a value much smaller than the present rate of change inferred from LAGEOS data (—2.6 times 10 −9 cy −1 ). Half a billion years ago the value of the precessional constant, H , was about 25 per cent larger than it is now. This secular decrease of H is presumably an important factor if the astronomical theory of climate is to be extended beyond the Quaternary.