A sandy core may have kept Enceladus’ ocean warm
Friction in the icy moon’s heart could help explain its dramatic plumes
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. Friction within its porous core could help Saturn’s icy moon maintain a liquid ocean for billions of years and explain why it sprays plumes from its south pole, astronomers report November 6 in Nature Astronomy.
Observations in 2015 showed that Enceladus’ icy surface is a shell that’s completely detached from its rocky core, meaning the ocean spans the entire globe (SN: 10/17/15, p. 8). Those measurements also showed that the ice is not thick enough to keep the ocean liquid.
Other icy moons, like Jupiter’s Europa, keep subsurface oceans warm through the energy generated by gravitational flexing of the ice itself. But if that were Enceladus’ only heat source, its ocean would have frozen within 30 million years, a
