- The ocean showed itself not with plumes or pools but via subtle changes in Ganymede’s aurora, the moon’s version of the Northern Lights.
- Jupiter’s magnetic field should interfere with Ganymede’s, causing the moon’s aurora to rock back and forth by about 6 degrees. However observations showed that the aurora shifted by only about 2 degrees. The team deduced that an electrically conductive fluid beneath the surface — a saltwater ocean, for example — would create a secondary magnetic field that counteracted Jupiter’s interference.
- Jupiter’s moon Europa and Saturn’s moon Enceladus also hide subsurface oceans and researchers suspect that there may be water within Jupiter’s moon Callisto and the dwarf planet Ceres.
Aurora Shift Confirms Jupiter's Moon Ganymede Has an Ocean Too
3. 15. 15 by Alex Klokus