A sandy core may have kept Enceladus’ ocean warm

Friction in the icy moon’s heart could help explain its dramatic plumes

cutaway illustration of Enceladus

A HEART OF SAND  Friction in Enceladus’ porous core (illustrated in gray) could help heat the ocean (dark blue) beneath its icy surface (light blue) enough to stay liquid for billions of years.

JPL-Caltech/NASA

A soft heart keeps Enceladus warm from the inside.