Caltech Center for Comparative Planetary Evolution

The Caltech Center for Comparative Planetary Evolution (³CPE) is a virtual Center that invites all members of the Caltech community to participate. The goal of the ³CPE is to merge the fields of astronomy, geology, and biology to explore the origin and evolution of planetary systems and their biospheres. Addressing these questions requires research and insight which crosses traditional discipline boundaries. The ³CPE will be a catalyst for driving collaborations and forming a community spanning these disciplines. We will seed innovative partnerships bridging fields, provide opportunities for young scientists to expand their training into new areas, and help to develop a common culture linking these often well-separated disciplines.

Our biggest goal is to grow a community of people interested in an interdisciplinary approach to the study of comparative planetary evolution that will allow Caltech researchers to scientifically excel in new ways.

Explore more about the ³CPE, see the programs that the Center supports, examine research being undertaken by members of the Center, check out the next events happening within the center, or learn about recent happenings in related disciplines.

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Ganymede, Jupiter's largest moon and the largest in the solar system, is the only moon known to generate its own magnetic field. New research led by 3CPE postdoctoral scholar Kevin Trinh offers a surprising explanation: Ganymede's metal core may still be forming today.

Most dynamo models assume Ganymede formed hot and built its core early. Trinh and his colleagues instead modeled a moon that started cold and warmed slowly over billions of years, heated by radioactive decay and tidal squeezing from Jupiter. In their simulations, iron-rich melt gradually trickles down to the center, and that steady drip of dense metal both builds the core and stirs it, which can sustain a magnetic field. If they're right, Ganymede would be the only known world in the solar system where core formation is still under way. "I'm used to thinking of core formation being this ancient process," Trinh told Science. But the new work suggests it might be delayed by billions of years after a moon first forms.

The study was published in Science Advances in May 2026, and the idea may be tested when ESA's JUICE spacecraft reaches Ganymede in 2031.

Read the full story in Science · Learn more about Kevin's research