The Rotation of Venus: Part I. Atmospheric Tides. Part II. Obliquity and Evolution

Author: Dobrovolskis, Anthony Robert

Year: 1979

Degree: Dissertation (Ph.D.)

Advisor: Ingersoll, Andrew P.

Committee Member: Unknown, Unknown

Option: Planetary Sciences; Astronomy

DOI: 10.7907/0g1y-7e13

Abstract

Earth-based radar observations reveal that the surface of Venus rotates very slowly in the retrograde sense, Tides raised by the sun in the body of Venus tend to slow its rotation further. The spin of Venus might be in a steady state if thermal tides in the atmosphere balance the tidal torque on the crust. Part I of this dissertation presents a quantitative theory of atmospheric tides applicable to Venus. It is found that the thermal tide is capable of maintaining the rotation of Venus in its current state indefinitely.

Part II examines the effects of obliquity, the frequency­ dependence of the tides, core-mantle coupling, possible resonances, and other phenomena. It appears most likely that Venus originated with an obliquity greater than 90°.

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