The accretion of new material during Pluto’s formation may have generated enough heat to create a liquid ocean that has persisted beneath an icy crust to the present day. This ‘hot start’ scenario contrasts with the traditional view of Pluto’s origins as a ball of frozen ice and rock in which radioactive decay could have eventually generated enough heat to melt the ice and form a subsurface ocean.
Click here for original story, Evidence supports ‘hot start’ scenario and early ocean formation on Pluto
Source: ScienceDaily