Galileo magnetometer measurements: a stronger case for a subsurface ocean at Europa.
On 3 January 2000, the Galileo spacecraft passed close to Europa when it was located far south of Jupiter's magnetic equator in a region where the radial component of the magnetospheric magnetic field points inward toward Jupiter. This pass with a previously unexamined orientation of the external forcing field distinguished between an induced and a permanent magnetic dipole moment model of Europa's internal field. The Galileo magnetometer measured changes in the magnetic field predicted if a current-carrying outer shell, such as a planet-scale liquid ocean, is present beneath the icy surface. The evidence that Europa's field varies temporally strengthens the argument that a liquid ocean exists beneath the present-day surface.
Kivelson
M G
MG
Institute of Geophysics and Planetary Physics, University of California, Los Angeles, CA 90095-1567, USA. mkivelson@igpp.ucla.edu
Khurana
K K
KK
Russell
C T
CT
Volwerk
M
M
Walker
R J
RJ
Zimmer
C
C
D005118:Extraterrestrial Environment; D007053:Ice; D018538:Jupiter; D008280:Magnetics; D014867:Water
D007053:Ice; D014867:Water