Innermost inner core

Innermost inner core upsc
  • The new layer is a solid metallic ball of nickel and iron and is deep inside the inner core of Earth.
    • Therefore, it is dubbed the “innermost inner core”.
  • The ‘innermost inner core’ may be an iron ball with a radius of about 650 kilometres inside the inner core.
  • It is solid due to high pressure deep within the Earth that stops iron alloy from melting.
  • First hypothesised about 20 years ago, it was identified through data gathered from seismic waves caused by earthquakes.

Significance of the Fifth layer

  • Provide information on past events on Earth that happened hundreds of millions to billions of years ago.
  • Provide a new way to probe Earth’s inner core and its centremost region.
  • Provide information about the evolution of the earth’s magnetic field etc.

The Four Layers of the Earth

So far, four layers of Earth’s structure had been identified. This includes:

  1. Crust
    • It is the topmost or outermost layer of Earth, which makes up 1% of Earth’s Volume.
    • It has two parts – a thinner Oceanic Crust and a thicker Continental Crust.
  2. Mantle
    • Solid/plastic layer of earth which makes up about 84% of Earth’s Volume.
    • It is divided into two parts – Upper Mantle and Lower Mantle.
    • The uppermost mantle and crust constitute the lithosphere.
  3. Outer core
    • The liquid portion of the core
    • It is composed of 80% iron along with nickel and some other lighter elements.
  4. Inner core
    • The solid portion of the core,
    • It is composed of Iron and nickel with the presence of heavy elements like gold, platinum, palladium, silver and tungsten.
    • It was believed that it was the hottest and densest of all layers.
      • However, this new layer is denser than the other two cores.

Interesting Facts about Earth’s Layers

  • Scientists can drill holes to study the earth’s crust but in order to study deeper layers they must study seismic waves.
  • Iron and nickel are considered the two major components found on the earth’s core.
    • It is believed that 80 per cent of the earth’s core is made of iron.
  • There is enough gold in the core of Earth to cover the entire surface of the Earth in a 4-meter thick layer.
  • The layer of the earth’s crust covering the entire planet is referred to as the “sima”.

Latest news about Innermost inner core

  • 01 March 2023:
    • A team of researchers has found evidence of a new layer of the planet sitting within the inner core.
    • According to seismologists from The Australian National University (ANU), data gathered from seismic waves caused by earthquakes has shed new light on the deepest parts of the Earth’s inner core.


  1. Times Now News
  2. Wikipedia

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