True, but to be fair the parent said "not long ago" and this is quite the case, it was only ten years ago that we first observed vapour plumes on Enceladus, and

True, but to be fair the parent said "not long ago" and this is quite the case, it was only ten years ago that we first observed vapour plumes on Enceladus, and I think Europa's subsurface ocean hypothesis started to gain traction around the same time. We live in exciting times.