Earth's Core

Earth

Earth, the planet we inhabit, is the third from the sun. It is not only the largest terrestrial planet in the solar system, but also ranks in terms of mass, diameter and density. Our planet is home to millions of living species and is the only planet known to support life. Formed more than 4.50 billion years ago, the biosphere has consistently altered its atmosphere and abiotic conditions. The presence of aerobic organisms, the ozone layer and the magnetic field, all make the planet unique.

Earth's outer surface or crust is made up of a number of segments or tectonic plates. These plates migrate over the surface, which is covered by 71% water and 29% land. The earth's interior is persistently active and homes a layer of solid mantle, liquid outer and an inner core that is concentrated in iron content. This is the reason behind the magnetic field generated around the planet. The planet's mineral resources, biosphere components and their interdependency and the presence of water are responsible for the survival of life forms.

The Earth's Core

The earth is an oblate spheroid. It is a sphere that bulges around the equator. With a mass of 5.98 × 1024 kg, the planet is composed of iron, oxygen, silicon, magnesium, sulfur, nickel, calcium, aluminum and traces of other elements. The core is mainly composed of iron, nickel and sulfur. The interior of the Earth is subdivided into chemical and physical layers, each with its own unique properties. The solid outer crust is held in place by a solid mantle that is viscous in nature. Beneath this mantle region lies a liquid outer core that protects a solid inner molten core that displays angular velocity. These two layers make up the total core of the planet.

How Hot is the Earth's Core?

The inner core of the earth has a temperature that could rise beyond 6,000 K and the generated pressure could build up to more than 300 GPa. Volcanic activity and seismic waves contribute to and arise from these extreme conditions. The inner core is about 1,220 km in radius and primarily comprises of an iron-nickel alloy. The temperature within the core is believed to be similar to that on the sun's surface. Very little is actually known about earth's inner core. It is believed that the region is gradually cooling to a homogeneous, clean layer. However, seismologists reveal that the earth's inner core enables the passage of seismic waves rapidly, in all directions. The molten inner core is believed to be composed of layers. Each of these is separated by some sort of transition zone.

Why is the Earth's Core So Hot?

The outer core of the earth does not have the ability to allow shear waves to pass through and hence compressional waves are generally observed in the region. The composition of the inner core, a nickel-iron alloy, is what makes the region very hot. These elements keep heating at the high temperature 'locked' within, with even the iron content melting at the dramatically high pressure generated. Research reveals that there is a super-rotation of seismic waves within the inner core and this property is responsible for one degree of extra rotation every year. The composition and trapped heat within the inner core region is what generates a magnetic field due to a dynamo action. The dynamo action is generated within the liquid outer core surface.