Eris and Makemake might be hiding unexpected oceans of liquid water

Icy rocks in the outer solar system might have unexpected subsurface oceans. Eris and Makemake are both dwarf planets in the Kuiper belt – the ring of frozen objects that encircles our solar system beyond Neptune’s orbit – and new observations from the James Webb Space Telescope (JWST) hint that these small worlds could have unexpected activity beneath their surfaces.

Kuiper belt objects, or KBOs, are generally thought of as similar to large, inactive comets, preserving pristine ices that formed in the early solar system. But Christopher …