Unit 3.3: Core

• The core is the innermost layer of Earth.
• Core


  It is 3480 km thick and its depth starts from 2900 to 6380 km
• Lehmann discontinuity


  The boundary between the inner and outer core
• In the early years of Earth’s formation, dense materials such as iron and nickel sank to the center forming the core.
• In general, the core is composed mainly of iron which is about 85%.
• Nickel is also present at 5% alongside other lighter elements which are 10% of the layer
• Other lighter elements which are 10% of the layer

  These lighter elements include sulfur, oxygen, carbon, and hydrogen. These lighter elements play an important part in the convection of the outer core which is fluid, hence, was able to generate Earth’s magnetic field.
• The core can be divided into two parts: outer and inner core. Seismic studies are also responsible for discovering these two layers of the core
• outer core


  is a liquid layer, 2260 km thick. The temperature in this region is very high allowing the melting of materials
• The temperature in the outer core ranges from 4500 °C to 6000 °C. The turbulent flow of iron in the outer core is believed to be responsible for the generation of Earth’s magnetic field
• The inner core is the innermost layer of Earth.
• inner core


  It is also composed of iron and nickel and light elements. Unlike outer core, this layer is in the solid phase. This was also discovered through seismic studies. The temperature in this region ranges from 6000°C and higher, but the pressure is high enough for the materials to stay solid. The inner core is about 70% of the size of the Moon
• The temperature in the inner core is the same as the temperature at the surface of the sun.
• Researchers believed that the core was already formed when the Solar System was very young
• Data showed that the core was formed around 1 to 1.5 billion years ago when the solid inner core was just beginning to solidify. This accounts for the increasing magnetic field strength of Earth compared to the beginning fluid core.
• Studies also explained that compared to the earlier years of Earth when the core was in a rapid change of state from liquid to solid, the cooling in the inner core was slower today. This solidifying process of the inner core strengthens Earth’s magnetic field.