The definition of a finger is a digit on your hand or anything that looks like or functions like a finger. Thumb - The thumb is the short, stubby finger that can rotate in all directions (opposable thumb). The anatomical name for the thumb is the 1st finger.
Pluto is thought to be made of mostly ice. It probably also has a small rocky core which might contain some metals. The ice on the surface of Pluto is made of frozen nitrogen, methane and carbon monoxide. The ice covering Pluto reflects a lot of sunlight making it appear brighter than it would if it had been covered with a darker rocky material. 1  Javascript must be enabled to use Cool Cosmos.
Planetary scientists have calculated Plutoâs density at between 1.8 and 2.1 g/cm 3. From this density, they have calculated that its interior is probably 50-70% rock and 30-50% ice. Decaying radioactive elements inside Pluto would heat the interior of the dwarf planet, allowing the rock and ice to move around. At this point, the interior of Pluto is probably a rocky core surrounded by a shell of ice.