THE INNER CORE: UPSC Daily Important Topic | 15 February 2022

THE INNER CORE

◇ Inner core extends from the centre of the earth to 5100 km below the earth’s surface.

◇ Inner core is generally believed to be composed primarily of iron (80%) and some nickel (nife).

◇ Since this layer can transmit shear waves (transverse seismic waves), it is solid. (When P-waves strike the outer core – inner core boundary, they give rise to S-waves).

◇ Earth’s inner core rotates slightly faster relative to the rotation of the surface.

◇ The solid inner core is too hot to hold a permanent magnetic field.

◇ The density of the inner core ranges from 12.6 g/cm3 to 13 g/cm3.

◇ The core (inner core and the outer core) accounts for just about 16 percent of the earth’s volume but 33% of the earth’s mass.

◇ Scientists have determined the temperature near the Earth’s centre to be 6000֯C.

◇ At 6000°C, this iron core is as hot as the Sun’s surface, but the crushing pressure caused by gravity prevents it from becoming liquid.