Here's how Europe's JUICE spacecraft will look for alien oceans


"There never was a good war, or a bad peace."
I think this treats the subject very well. Ever since these oceans were imagined they have taken over the old role of Mars.
I mean this in a nice way. The ideas of oceans kept relatively warm by internal heat - nuclear or from friction (from orbiting close to gas giants). The right ingredients are there.

The limitation, of course, is how far aqueous based life can progress. Without electricity, without computers - we are forced to 'mental' development. Bacteria controlling atomic processes by telepathy - and off we go . . .