EARTH’S INNER CORE (Syllabus: GS Paper 1 – Geography)

News-CRUX-10     9th July 2024        

Context: Recent studies by scientists indicate that the Earth's core has slowed down significantly, potentially reversing its direction of movement.

Earth’s Inner Core

  • About: The innermost part of Earth, located approximately 5,150 kilometers beneath the surface.
  • Composition: Primarily of iron and nickel, forming a solid metallic ball.
  • Mass: Makes up around 20 percent of Earth’s total mass.
  • Size: Has a radius of about 759 miles (1,221 kilometers).
  • Temperature and Heat Sources: Extremely hot, with temperatures ranging from 7200–9000℉ (4000–5000℃).
  • Heat generated by radioactive decay, residual heat from planetary formation, and heat from outer core solidification.
  • Pressure: Under intense pressure of about 3.6 million atmospheres, which maintains its solid state despite high temperatures.
  • Surrounding Layers: Outer core, a superhot layer of molten metals, and further by the mantle and crust.

o The boundary with the outer core is known as the Lehman Seismic Discontinuity.

  • Magnetic Field: Generates its own magnetic field.

o Contains about 10% of the Earth's total magnetic field energy despite its small volume.

Rotation speed of Earth's core slowing down

  • Discovery of Earth's Inner Core: Danish seismologist Inge Lehmann discovered the planet's inner core in 1936, sparking ongoing scientific inquiry into its properties.
  • Challenges: Direct observation and sampling of Earth's deep interior are impossible, leading scientists to rely on indirect methods for understanding core dynamics.
  • Seismographic Evidence: Data from seismograms, measuring waves from earthquakes and explosions, provide crucial insights into the Earth's core rotation.
  • Recent Findings: A study published in June found that the solid inner core's rotation speed has been consistently decreasing relative to the Earth's surface.