Did the flyby of Europa on Jan. 3rd 2000 prove an ocean exists?
Inside EuropaAs the spacecraft flew 351 kilometers above the icy moon on January 3, 2000, its magnetometer instrument studied changes in the direction of Europa’s magnetic field. Galileo’s magnetometer observed directional changes consistent with the type that would occur if Europa contained a shell of electrically conducting material, such as a salty, liquid ocean. We think these findings tell us that there is indeed a layer of liquid water beneath Europa’s surface. It appears that the ocean lies beneath the surface somewhere in the outer 100 kilometers, the approximate thickness of the ice/water layer. Jupiter’s magnetic field at Europa’s position changes direction every 5 hours – this changing magnetic field can drive electrical currents in a conductor, such as an ocean. Those currents produce a field similar to Earth’s magnetic field, but with its magnetic north pole (the location toward which a compass on Europa would point) near Europa’s equator and constantly moving.
As the spacecraft flew 351 kilometers above the icy moon on January 3, 2000, its magnetometer instrument studied changes in the direction of Europa’s magnetic field. Galileo’s magnetometer observed directional changes consistent with the type that would occur if Europa contained a shell of electrically conducting material, such as a salty, liquid ocean. We think these findings tell us that there is indeed a layer of liquid water beneath Europa’s surface. It appears that the ocean lies beneath the surface somewhere in the outer 100 kilometers, the approximate thickness of the ice/water layer. Jupiter’s magnetic field at Europa’s position changes direction every 5 hours – this changing magnetic field can drive electrical currents in a conductor, such as an ocean. Those currents produce a field similar to Earth’s magnetic field, but with its magnetic north pole (the location toward which a compass on Europa would point) near Europa’s equator and constantly moving. In fact, it is actually
