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The Missing Element In Earth's Core.

Byline: Roma B, Young Editor

Have you heard of the book or movie Journey to the Center of the Earth?

In it, the center of the Earth is filled with magical environments and bizarre creatures that keep the main characters, and the viewers, in a constant state of amazement.

However, the reality is not as fantastic: the Earth's core is thought to be made up of about 85% iron, 10% nickel, and 5% something else. A new study by Japanese researchers, led by Eiji Ohtani from Tohoku University, claims to have discovered what that "something else" isa an element we all know, silicon.

The Layers Of The Earth

The Earth is like a cake with many layers, and a depth of about 4500 miles. The first 10-25 miles consists of rocks and loose materials called the crust on which we live on. Think of it like the shell of an egg.

The layer below known as the Mantle, consists of super heated rock and makes up about 85% of the mass of the earth, and is 1,800 miles deep. Temperatures here get pretty hot. The lithosphere includes the crust and the hard upper mantle and is about 100 miles deep from the earth's surface. It floats on a layer called the asthenosphere - a silly putty like plastic material directly below it a few 100 miles in thickness. Volcanoes and earthquakes occur because of the activities of the lithosphere and asthenosphere's movements.

The next 1400 miles known as the Outer Core, is a heavy liquid iron layer. Scientists believe this layer is made of superheated molten lava made of iron and nickel. The layer below this is the Inner Core - a solid ball of iron and nickel with a diameter of 745-800 miles.

The Discovery

Scientists have not been able to account for the Earth's mass, and have been searching for the missing element that makes up Earth's Inner Core. Also, since the core is nearly 3,500 miles deep and cannot be accessed, the only way to study it is by monitoring how seismic waves travel through it. Seismic waves are energy waves, like the ones generated by earthquakes.

Japanese researchers had to use unusual methods to get an idea of the core's elemental makeup. They mixed iron, nickel, and silicon together to form an alloy (mixture of two or more metals). To simulate the environment in Earth's core, they then put the alloy under immense pressure and temperatures of 6000 degrees Celsius, or about 10,800 degrees Fahrenheit. They also recorded the seismic vibrations that came from the Earth's core. What did they find out? The vibrations from the test matched the results from the core's seismic activity!

While this isn't conclusive proof, it certainly seems to indicate that silicon is that missing element. This discovery may be a breakthrough at finding out what really happened when the Earth was formed 4.5 billion years ago, as reported by Simon Redfern, a professor of mineral physics at the University of Cambridge.

Check out this video on the discovery of Earth's core through analysis of seismic waves.

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Title Annotation:Our Earth
Publication:Youngzine
Geographic Code:1USA
Date:Jan 22, 2017
Words:615
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