Apparently the ocean on Enceladus is kept warm due to geothermal heat. And that hear is accessible to the water because the ocean’s crust is very porous. Which

Apparently the ocean on Enceladus is kept warm due to geothermal heat. And that hear is accessible to the water because the ocean’s crust is very porous. Which naturally leads us to ideas like geothermal vents that may have been the source of life on Earth.