GS Paper 1
Syllabus: Geography – Physical Geography of the world.
Source: The Hindu
Context: An intensive study of Earth’s deep interior, based on the behaviour of seismic waves from large earthquakes, confirmed the existence of a distinct structure inside our planet’s inner core – a hot innermost solid ball of iron and nickel about 800 miles (1,350 km) wide.
- The planet’s internal structure comprises four layers: a rocky crust on the outside, then a rocky mantle, an outer core made of magma, and a solid inner core.
- The inner core’s outer shell and its newly confirmed innermost sphere both are hot enough to be molten but are a solid iron-nickel alloy because the incredible pressure at the centre of the Earth renders it a solid state.
- The inner core is slowly growing in size at the expense of the outer core by solidifying molten materials as Earth gradually cools.
Related News:
New studies reveal insights about Earth’s mysterious mantle
Source: DTE
Context: According to a new study, the mantle — a 2,900 km thick layer of solid rock sandwiched between the Earth’s upper crust and lower core — has been hiding two layers.
- One is the “low viscosity” zone in the upper mantle.
- The other layer is the low-velocity zone, which is also a part of the upper mantle.
Significance of this layer:
- Affects how Earth transports heat and mixes materials between the crust, core, and mantle over time.
- The mantle’s viscous properties govern convection — the transfer of heat between areas of different temperatures, enabling plate tectonics.
- The viscosity of the rocks in the transition zone between the upper and the lower mantle determines whether a plate sinks below another one (subduction) through
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