Question

The innermost layer of the earth is?
A.Crust
B.Core
C.Mantle
D.None of the above

Answer 1

Hint:The surface of the world is an incredible spot to behold. The Earth consists of four distinct layers, beginning at the middle from deepest to shallowest.

Complete answer:
The four layers of Earth are the inner core, the outer core, the mantle and the crust.
The inner core is a solid metal ball with a radius of 758 miles (1,220 kilometres), or about three-quarters of that of the earth. It sits about 6,400 to 5,180 kilometres (4,000 to 3,220 miles) below the surface of the Earth. Extremely thick, much of it is made from iron and nickel. A little faster than the rest of the planet, the inner centre spins. It's intensely humid too. There are tremendous pressures here: well over 3 million times more than on the surface of the Earth. Some study indicates that an inner, internal heart can also occur. It would therefore almost exclusively consist of iron.

The outer core, in liquid form only, is also made from iron and nickel. It stays below the surface for some 5,180 to 2,880 kilometres (3,220 to 1,790 miles). This liquid churns in massive, swirling waves, heated primarily by the radioactive decay of the elements uranium and thorium. Electric currents are produced by the motion. They, in essence, create magnetic fields on Earth.At about 3,000 kilometres (1,865 miles) deep, the mantle is the thickest material on Earth. It begins just 30 kilometres (18.6 miles) below the surface. It is thick, hot and semi-solid, made up of iron, magnesium and silicon (think caramel candy). This one often circulates, like the one below it. It only does this much more slowly.

The surface of the world resembles the shell of a hard-boiled egg. Compared with what lies underneath it it is incredibly weak, cold and brittle. The crust is made of elements that are relatively light, especially silica, aluminium and oxygen. The thickness of it is also extremely variable. It can be as little as 5 kilometres (3.1 miles) deep under the oceans (and Hawaiian Islands). The crust can be 30 to 70 kilometres (18.6 to 43.5 miles) deep under the continents.

Hence, the correct answer is option (B).

Note:For direct calculation, there are no measurements of the Earth's core available, as there are for the Earth's mantle. Knowledge regarding the centre of the Planet often emerges from seismic wave research and the magnetic field of the Earth.