As we go deeper into the Earth, we find many different layers. The innermost part of the Earth is called the inner core. This is the deepest part of the Earth's surface, a region that we will probably never be able to access.

The inner core is a spherical ball, whose radius is about 70% of that of the Moon! It is mostly made of an iron-nickel mixture. Its temperature is about $$5500^{\circ} \, \text{Celsius}$$, the same as the temperature of the Sun's surface! Even though the temperature is so high, the iron-nickel mixture remains a solid in the inner core. We shall understand the reason behind this at the end of the module.

Pre-requisites: Matter In Our Surroundings 1