According to the researchers, Charon - Pluto's largest moon - could have had a subsurface ocean in ancient times. The conclusions were made by analyzing the images sent by the New Horizons apparatus.
The research results were presented on the NASA website. As you know, Charon is the largest satellite of the dwarf planet Pluto. It was opened in 1978, and in 2015 the New Horizons station managed to explore the object from a flyby trajectory. Now, when studying the images, scientists drew attention to some features of the satellite's relief. They arise when water expands during its transition from a liquid to a solid phase. Probably, the formation of numerous cracks, ledges and valleys was caused by the stretching of the surface of Charon by internal matter.
An example of such an object is the near-equatorial canyon, which received the unofficial name of Serenity Chasma. Its length is 1.8 thousand km, and its depth is 7.5 km. It is one of the largest canyons in the solar system. For comparison, the American Grand Canyon is 446 km long.
Scientists themselves believe that in ancient times Charon could have had a subsurface ocean. The fact is that at that time the satellite's temperature was much higher. Charon gradually cooled down, and the water inside him froze, causing fractures. Scientists will be able to finally confirm their guesses in the future, after a more detailed consideration of this issue.