Planets are the bodies that revolve around the sun. These bodies do not give enough light that can easily seen by our eyes but sometimes we see the planet because the light of sun falling on them gets reflected and reaches to us. Our solar system comprises of nine planets which are made up of different material and gases.
Mercury is made up of dense iron core and silicate mantle and crust. It has lost its atmosphere because mercury is very close to the sun.
Venus is made up of nickel and iron in its interiors but it has not been proved yet and the gas present on the Venus is carbon dioxide.
Earth is composed of iron. And nearly 30% of it is found in its core. Earth also has 30% of oxygen and 14% of magnesium.
Mars also comprises of iron like the other three planets. With the iron it has 16% of sulfur present in its core and silicate mantle.
It is speculated that the largest planet in solar system i.e. Jupiter is made up of rocky core and the main bulk of Jupiter consists liquid metallic hydrogen. There is 90% of hydrogen and only 10% of helium on the Jupiter.
Saturn has approximately same percentage composition as that of the Jupiter but this planet is very hot from inside and gives more radiation as compared to what it receives from the sun.
Uranus is mostly made up of rocks and ice which is formed by the mixture of water and gases (ammonia and methane). Its atmosphere is made up of 83% of hydrogen.
Neptune is also made up of rock and ice but there is nearly 15% of hydrogen in its atmosphere.
Very less is known about the planet Pluto and now it is not taken as the planet by the scientists.
The rocky planets have the solid core and surface but they may not have the molten region like the earth has. On the other hand the gaseous planets have little solid core and there main composition is clouds of gas for e.g. Jupiter.