Question

Why do the giant planets and their moons have compositions different from those of the terrestrial planets?

Answer 1

Answer and Explanation:

The formation of planets ,initially was the result of gradual accumulation of  solid matter into the solar nebula. As a result of high temperature in the interior of our solar system, metals and rocks were the only materials to get compressed.

The matter that was volatile could not be compressed so close to the heat energy radiated by the early Sun.

On the outer part of the solar system, solid matter included hydrogen compounds, rocks and metals  with a lot of matter for planet formation.

The Giant planets were formed by capturing Helium and hydrogen gases as well whereas the terrestrial planets being much more smaller are made up of mainly rocks like silicates and metals like iron.

The moons of terrestrial planets like that of Earth is also terrestrial in nature consisting of rocks and metals as the constituent material while that of giant planets consist of frozen water in half the proportion and the other half is rocks and metals.