Europa Could Have More Ocean Than Earth, Enceladus Sprays Its Ocean into Space

Earth isn’t the Solar System’s sole water world: Europa’s subsurface ocean may hold about 3 billion cubic kilometres of liquid water—roughly twice the volume of Earth’s oceans—while Enceladus vents ocean material into space via its south-pole plumes, offering direct sampling opportunities. The concept of a single “ultimate water world” is too simplistic; water exists in diverse forms—volume, location, chemistry and accessibility—across the Solar System, and neither moon has found life evidence yet.