title: Titan's rotation reveals an internal ocean and changing zonal winds.
abstract: Cassini radar observations of Saturn's moon Titan over several years show that its rotational period is changing and is different from its orbital period. The present-day rotation period difference from synchronous spin leads to a shift of approximately 0.36 degrees per year in apparent longitude and is consistent with seasonal exchange of angular momentum between the surface and Titan's dense superrotating atmosphere, but only if Titan's crust is decoupled from the core by an internal water ocean like that on Europa.
authors: Space Department, Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA. ralph.lorenz@jhuapl.edu
authors: Ralph D
authors: RD
authors: Lorenz
authors: Bryan W
authors: BW
authors: Stiles
authors: Randolph L
authors: RL
authors: Kirk
authors: Michael D
authors: MD
authors: Allison
authors: Paolo Persi
authors: PP
authors: Del Marmo
authors: Luciano
authors: L
authors: Iess
authors: Jonathan I
authors: JI
authors: Lunine
authors: Steven J
authors: SJ
authors: Ostro
authors: Scott
authors: S
authors: Hensley
mesh_terms: D001272:Atmosphere; D005118:Extraterrestrial Environment; D007053:Ice; D018539:Saturn; D018531:Spacecraft; D014867:Water; D014919:Wind
chemical_list: D007053:Ice; D014867:Water