Pluto's density is 1.8 g/cm³. Iron is about 5 g/cm³. Rock is about 3 g/cm³. Ice or water is 1.0 g/cm³. This implies that A) Pluto has a large iron-nickel core. B) Pluto is about 35% water ice and 65% rocky material. C) Pluto is all rock. D) Pluto is all water or water ice.

Question

Quizplus · Accepted Answer

Pluto's density is less than that of iron, which means it can't be made up entirely of iron. It's also denser than rock, so it must have a significant amount of heavy material like iron, but not as much as Earth or the other terrestrial planets. However, its density is similar to a mixture of rock and water ice, which implies that Pluto is made up of about 35% water ice and 65% rocky material.

Pluto's Density Is 1