What supplies the heat that keeps Enceladus's ocean liquid?
In plain words
Enceladus is a small moon of Saturn that sprays water from cracks near its south pole and loses far more heat than a body its size should. Tidal flexing by Saturn is the likely source, but where inside the moon it is turned into heat, and whether the ocean is in balance, is unclear.
Precise statement
Identify where tidal energy is dissipated in Enceladus (porous rocky core, ice shell, or ocean) to supply the observed heat loss of order $10^{17}\ \mathrm{erg}/\mathrm{s}$, and whether this rate is in steady state with orbital evolution in the $2:1$ resonance with Dione or reflects an episodic phase. An answer is a dissipation distribution and heat budget consistent with the measured libration, shell thickness variations and plume activity.
What would settle it
A measured total heat budget and tidal response (Love numbers and phase lag) matched by an interior model with a specified dissipating layer and orbital evolution rate.
Status in the literature
Unverified note
Miles et al. 2025 (Science Advances) reported endogenic heat flow at the north pole as well, raising the total heat-loss estimate.