What is the Meaning & Definition of the core of the Earth

The core of the Earth is the name that receives the central sphere and more internal of planet Earth. Among its key components we have nickel and iron, a greater proportion and to a lesser extent with oxygen and sulphur. The radio has approximately 3,500 kilometers, a magnitude that is larger than the planet Mars and its internal pressure is millions of times more important that which holds the Earth's surface. Its temperature is really very high and can reach the 6700°, even hotter is that surface presenting the footballer sol, meanwhile, is that this has to do with the heat that resulted from the collision of particles when the Earth was formed.
The outer core is liquid and consists of iron, nickel and other less-dense components, while the inner is solid texture and also has iron, approximately 70% and 30% nickel, and then are other heavy metals such as titanium, Iridium and lead.
The Earth's core was formed along with this makes some five billion years ago after the explosion of a supernova. Excess heavy metals gathered in album, revolving around the Sun. The core mostly composed of iron and other elements such as uranium and plutonium radioactive released heat and then by gravity the heavier materials sank in the middle and the lightest floated up to the crust. Such a process is known as planetary differentiation. And by this fact is that the Earth's core is composed of iron, nickel, Iridium, among others, which are as already discussed heavy materials.
To be noted is that when our planet was burning metals that now make up its core suffered an alloy which became a very dense structure and strong and case is that the planet Earth is the most dense of our system.