In the structure of planet Earth, below the mantle, the core is mainly made up of:

The correct answer is Iron and Nickel.

Key Points

• The core of the Earth consists primarily of iron (Fe) and nickel (Ni), with iron being the predominant element.
• The Earth's core is divided into two layers: the outer core (liquid) and the inner core (solid).
• The inner core is composed of approximately 80-85% iron, along with nickel and trace amounts of lighter elements such as oxygen, sulfur, or silicon.
• The outer core generates the Earth's magnetic field through the motion of liquid iron and nickel, a process known as the geodynamo.
• The core's high temperature and pressure make it one of the most extreme environments on Earth, with the inner core reaching temperatures of up to 5,700°C (comparable to the surface of the Sun).

Additional Information

• Earth's Layers:
  • The Earth is divided into three main layers: crust, mantle, and core.
  • The core lies beneath the mantle and is about 3,500 kilometers in radius.
• Seismic Evidence:
  • The composition of the Earth's core is inferred from seismic wave studies, as direct sampling is not possible.
  • Seismic waves behave differently when traveling through solid versus liquid, helping scientists understand the core's structure.
• Density and Composition:
  • The high density of the core (around 12-13 g/cm³) aligns with iron and nickel's physical properties.
  • Light elements such as sulfur or silicon may also be present in small amounts in the outer core.
• Geodynamo Effect:
  • The Earth's magnetic field arises due to the movement of molten iron and nickel in the outer core.
  • This phenomenon is critical for shielding the planet from harmful solar and cosmic radiation.
• Formation of the Core:
  • The Earth's core formed during the planet's early stages, as heavier elements like iron and nickel sank towards the center due to gravity in a process called planetary differentiation.