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The moments of inertia of Mars
Author(s) -
Bills Bruce G.
Publication year - 1989
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl016i005p00385
Subject(s) - mars exploration program , moment of inertia , ellipsoid , hydrostatic equilibrium , oblate spheroid , gravitational field , physics , moment (physics) , venus , component (thermodynamics) , geophysics , geology , geodesy , classical mechanics , astrobiology , thermodynamics , astronomy
The mean moment of inertia of Mars is, at present, very poorly constrained. The generally accepted value of 0.365 MR² is obtained by assuming that the observed second degree gravity field can be decomposed into a hydrostatic oblate spheroid and a nonhydrostatic prolate spheroid with an equatorial axis of symmetry. An alternative decomposition is advocated in the present analysis. If the nonhydrostatic component is a maximally triaxial ellipsoid (intermediate moment exactly midway between greatest and least) the hydrostatic component is consistent with a mean moment of 0.345 MR². The plausibility of this decomposition is supported by statistical arguments and comparison with the Earth, Moon and Venus. If confirmed, this new value would have significant implications for the inferred composition and climatic history of Mars. The Mars Observer mission may help resolve this issue.