Core of Solar System's largest moon may still be forming: Ganymede discovery could force rethink of how worlds power their magnetic fields.

The article focuses on new research suggesting that Ganymede, Jupiter’s largest moon, may have a still-forming metallic core powering its magnetic field, challenging previous assumptions that such core formation occurs only early in a world’s history. Unlike Earth’s magnetic dynamo driven by convective motions in a fully formed molten core, Ganymede’s dynamo might result from ongoing iron accumulation and stirring within a gradually developing core. This hypothesis arises from models assuming Ganymede started cold and warmed slowly over billions of years through radioactive decay and tidal heating. Upcoming data from the European Space Agency’s Jupiter Icy Moons Explorer (JUICE) mission, arriving in 2031, could provide critical insights into Ganymede’s internal structure and magnetic properties to test this theory. [Extracted from the article]