Write a note on the Earth.

Earth is the third planet from the Sun. This is the only planet in the solar family which support life. It has a thin layer of the atmosphere. The thickness of this layer is about 800 to 1000 km. This atmosphere protects us from meteors by burning and that gets converted to gaseous matter. It also contains one of the most important layers i.e. ozone layer that is responsible for absorbing ultraviolet rays of the sun. The outer layer of earth is made up of mud or rocky stones (silicate). Its core region contains semi-liquid made up of molten iron, magnesium like substance. It has one natural satellite, the moon.