Europa is smaller than Earth's Moon, yet the ocean locked beneath its ice contains more liquid water than every ocean on Earth combined — kept from freezing not by sunlight, but by Jupiter's gravity squeezing the moon like a slow, endless fist - spacedaily.com
Source:Space Daily
A distant moon harbors a hidden ocean vaster than Earth’s—sustained not by warmth from above, but by the relentless gravitational squeeze of its giant host.