The highly-reflective surface of Saturn’s icy moon, Enceladus, indicates the presence and abundance of consistently fresh surface ice, like no other moon in the Solar System. Image credit: NASA / JPL-Caltech / Space Science Institute.

Ask Ethan: How Can Worlds That Never Get Above Freezing Have Liquid Water?

How three factors come together to unfreeze the ice, and unlock the potential for extraterrestrial life.

Ethan Siegel
Sep 30, 2017 · 7 min read

“Day after day, day after day,
We stuck, nor breath nor motion;
As idle as a painted ship
Upon a painted ocean.

Water, water, every where