Cracks in Pluto's Moon Could Indicate it Once Had an Underground Ocean: If the icy surface of Pluto's giant moon Charon is cracked, analysis of the fractures could reveal if its interior was warm, perhaps warm enough to have maintained a subterranean ocean of liquid water, according to a new NASA-funded study. This artist concept shows Pluto and some of its moons, as viewed from the surface of one of the moons. Pluto is the large disk at center. Charon is the smaller disk to the right. Image Credit: NASA, ESA and G. Bacon (STScI) #nasa #space #pluto #charon #solarsystem #moon #ice #science