The Possible Others
In the previous seven chapters, we have investigated seven icy satellites and two dwarf planets within our Solar System. Five of those have already been confirmed as ocean worlds, whereas four are very likely to host a subsurface ocean (or at least a subsurface sea in the case of Ceres), but conclusive evidence is still pending. That our Solar System can host so many planetary objects capable of sustaining large amounts of liquid water is remarkable. Still, there is potential for more. In this chapter, we will consider the possibility of subsurface oceans in other icy satellites and trans-Neptunian objects (TNOs) for which we currently have little or no observational data. Some of these objects might be confirmed as ocean worlds in the coming decades, while others might have past subsurface oceans only.