Related Experiment Video
Updated: May 8, 2026
11:47
A 100 KW Class Applied-field Magnetoplasmadynamic Thruster
Published on: December 22, 2018
Powering Ganymede's dynamo with protracted core formation
Kevin T Trinh1, Flavio Petricca2, Douglas J Hemingway3
1Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91101, USA.
Science Advances
|May 6, 2026
Summary
Ganymede
Area of Science:
- Planetary Science
- Geophysics
- Astrobiology
Background:
- Ganymede is the only moon in our solar system with an active magnetic field.
- Previous research suggested its magnetic field originated from a metal core formed billions of years ago.
Purpose of the Study:
- To reevaluate Ganymede's thermal evolution and core formation.
- To explain the moon's persistent magnetic dynamo.
Main Methods:
- Thermal evolution modeling of Ganymede's interior.
- Analysis of core formation processes from a "cold start" accretion scenario.
Main Results:
- Ganymede's dynamo may be sustained by ongoing core formation, a novel concept.
- A continuously forming iron-sulfur (Fe-FeS) core can explain the dynamo.
Conclusions:
- Ganymede's magnetic field does not require an ancient metal core.
- Ongoing core formation provides a viable mechanism for Ganymede's long-lived dynamo.
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