Lunar rotational dissipation in solid body and molten core

摘要: Analyses of Lunar Laser ranges show a displacement in direction the Moon's pole rotation which indicates that strong dissipation is acting on rotation. Two possible sources are monthly solid-body tides raised by Earth (and Sun) and fluid core with distinct from solid body. Both effects have been introduced into numerical integration lunar Theoretical consequences orbit also calculated analytically. These computations indicate tide signatures separable. They allow unrestricted laws for tidal specific Q versus frequency to be applied. Fits detect three small terms addition dominant pole-displacement term. Tidal alone does not give good match all four amplitudes. Dissipation plus accounts them. The best increases slowly period core. size depends imperfectly known properties core-mantle interface. radius could as much 352 km if iron 374 Fe-FeS eutectic composition. If assumed represented power law, then exponent −0.19±0.13. 37 (−4,+6), annual 60 (−15,+30). presently dissipated body small, but it may dramatic early Moon. outwardly evolving Moon passed through change spin state caused burst mantle at boundary. energy deposited boundary plausibly drove convection temporarily powered dynamo. remanent magnetism rocks result these events, peak field mark passage transition.