Life on Pluto? Ocean, long thought to be frozen could be hidden, study claims Fox NewsA thin layer of gassy material on Pluto may be keeping an underground ocean from freezing solid Daily MailGas insulation could be protecting an ocean inside Pluto Phys.orgPluto Was Supposed to Be Fully Frozen - But It Looks Like It Has Liquid Oceans ScienceAlertWhat keeps Pluto's ocean from freezing?