Read at www.scientificamerican.com
Planetary scientists have discovered that Mimas, one of Saturn's moons, may have an oceanic world hidden beneath its icy shell. Previously, it was unclear whether liquid water existed on Mimas, but a new paper published in Nature suggests that an ocean may be present. This finding challenges previous assumptions about the existence of oceans in the icy moons of Jupiter and Saturn.
That's no moon; that's an oceanic world.
The discovery of oceans in the outer solar system moons has challenged the belief that heat from a moon's formation was necessary to prevent the seas from freezing solid. Previous spacecraft missions have confirmed the presence of oceans in Jupiter's Europa and Saturn's Enceladus, but it has remained uncertain for other moons like Mimas. The theory is that Mimas' elliptical orbit around Saturn causes enough internal friction and heat to sustain an ocean beneath its icy crust.
In principle, that squeezing creates sufficient internal friction and heat to melt ice and sustain an ocean.