Good news – the number of places in the Solar System to go for a swim increased today with the discovery of the signature of liquid water on Enceladus, one of the moons of Saturn.
This discovery was made by flying the Cassini satellite through one of the giant plumes of ice particles that erupt from cracks in its icy surface as shown in the images below (the second one has a bonus bit of Saturn included too).
(Credit: NASA/JPL/Space Science Institute)
What Cassini actually detected were negatively charged water ions; these are seen on Earth where water is in motion e.g. in waterfalls, so finding them here is a good indicator that liquid water exists under the exterior ice. If that’s true, then there must also be an internal heat source to keep it that way, and maybe even life swimming around out there too.