Right now there seems to be heat someplace inside the moon, possibly a great deal of it. On the surface, however, there is no sign of heat-no volcano, for example.

Volcanic activity on the moon could provide life-supporting heat, as well as important chemicals needed by living organisms.

This mixture took a leisurely million years or so to settle toward Titan's center—"plenty of time for heat to escape" and for the moon to cool into its present state, Iess said.