CURRENT AFFAIRS

Detailed explanation-1: -It is far too deep to investigate directly, so scientists study how seismic waves pass through this region to tell them something of its make-up.

Detailed explanation-2: -Silicon identified as ‘missing element’ in Earth’s core.

Detailed explanation-3: -Unlike the mineral-rich crust and mantle, the core is made almost entirely of metal-specifically, iron and nickel. The shorthand used for the core’s iron-nickel alloys is simply the elements’ chemical symbols-NiFe. Elements that dissolve in iron, called siderophiles, are also found in the core.

Detailed explanation-4: -A likely cause is that silicon is one of the light elements in the Earth’s core. We show that both the direction and magnitude of the silicon isotopic effect are in accord with current theory based on the stiffness of bonding in metal and silicate.

Detailed explanation-5: -Iron is the most abundant element, by mass, in the Earth, constituting about 80% of the inner and outer cores of Earth. The molten outer core is about 8000 km in diameter, and the solid inner core is about 2400 km in diameter.