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.
Pluto is 2,304 kilometers (1,432 miles) at the equator, and is only about the size of Russia. Pluto only has a mass of about one 400th that of Earth. Pluto is composed of several different materials, Pluto's thin crust is simply composed of ice, Pluto's mantel is quite rich in water and ice, Pluto's large core is probably about 70% rock, and 30% water ice.