Last year NASA’s New Horizons mission flew by Pluto, and showed evidence of an ocean on Pluto. Francis Nimmo, and James Tuttle Keane both astronomers working for NASA conducted a study. They found evidence that Sputnik Planitia, which is a large impact crater, or in other words a giant hole in the surface caused a meteor hitting the planet, is really heavy because of an underground ocean.
When the meteor hit it removed a large amount of ice from Pluto’s surface. Nimmo believes this caused half frozen water to well up underneath the surface. As the ice thickened on top Sputnik Planitia got heavier. The weight affected Pluto’s spin. Keane said that these studies show a very important relationship between the ice and Pluto's orbit. Most people find it hard to believe that ice can move a whole planet, but Pluto's surface and orbit is changing because of it.