Ganymede Ocean Currents Generate 9 nT Magnetic Signals, Aiding Juice's Search Beneath Ice
Updated
Updated · Astrobiology News · May 11
Ganymede Ocean Currents Generate 9 nT Magnetic Signals, Aiding Juice's Search Beneath Ice
2 articles · Updated · Astrobiology News · May 11
Simulations found Ganymede’s subsurface ocean can produce surface magnetic signals of up to 9 nanotesla, a level spacecraft magnetometers should be able to detect.
The effect arises when electrically conducting seawater flows through Ganymede’s own magnetic field, with strong east-west jets shearing field lines and creating a mainly toroidal induced field.
Researchers modeled both deep and shallow ocean cases and found the clearest signatures in deep-ocean scenarios with magnetic Reynolds numbers above 1, where ocean-driven signals can dominate some harmonic degrees.
Because the ocean is buried beneath kilometers of ice, magnetic sensing offers a rare indirect way to probe circulation tied to heat and material exchange relevant to habitability.
ESA’s Juice mission, already en route to Jupiter, could test the idea at Ganymede, with low-altitude orbits expected to improve sensitivity to the hidden ocean’s dynamics.
If Ganymede's ocean currents are confirmed, what is the next clue we need in the hunt for extraterrestrial life?
Could Ganymede's unique, still-forming core rewrite our understanding of how potentially habitable ocean worlds are born and sustained?