Tuesday, January 5, 2016

Jojo vs Earthquakes (Part 5)


We arrived at the end, - nearly, - of our journey through Earth's Layers.

Here in the depth of our planet lies the Core, although we should say Cores plural. The Core is viewed as a two distinct part region, both making the Core of the Earth, but in two different states - one liquid (Outer Core), one solid (Inner Core). It happen that, according to last research there could even be an inner inner core. Whatever way you look at it, it is extremely hot. The hottest part of the Core is at a nice 6000°C (10,800°F), or to put it differently, it is as hot as the surface temperature of our Sun. Not bad for a small planet...

Both layer are composed of the same alloy - Nickel-Iron. It is the pressure which dictates the state of the alloy. In the case of the Outer Layer, the nickel-iron alloy is in liquid form (10 times the viscosity of liquid metal on the surface of the Earth). In the case of the Inner Core, the nickel-iron alloy is in solid form because the pressure is so high that it prevents the alloy to become liquid.


THE OUTER CORE
When we quit the Mantle layer, we meet the Outer Core 2,890Km (1,800 Miles) beneath our feet. 
As mentioned above, the Outer Core is made up of a liquid nickel-iron alloy. It's temperature ranges from 4,030°C (7,280°F) at the Mantle-Core Boundary to 5,730°C (10,340°F) at the Outer-Inner Core Boundary. It's thickness is around 2,300Km (1,400 Miles).

THE INNER CORE
Continuing our travel through the Core, we finally reach the Inner Core 5,150Km (3,200 Miles) beneath Earth's Surface, it is the deepest layer of our planet. As solid ball of nickel-iron, it is massive sphere of 70% the Moon's Radius in size (around 1220Km radius or around 760 Miles). 
It is here that we find the highest temperatures (around 6000°C) and the highest pressure (between 330 and 360 Gigapascal - or in lay man's term between 3,3 millions and 3,6 millions the atmospheric pressure)


Since they are so deep in our planet we could think that it is not so important on our human level. After all don't we live way above the Core, on the Crust? 

But if you remember what I said in Jojo vs Earthquake (Part 2), the Earthquakes are born from the movement of the Crust, and that global Crust movement is a result of Convection Current formed deep into our planet due to heat transfer through Earth's Layers. So the heat below our feet is quite effective on us at the surface as a collateral (and sometimes deadly) effect.

Besides, the Core, and the interaction between the Inner and Outer layer of the Core is vital to us as it is the place where our Magnetic Shield is formed. 

Without the Magnetic Field created by the Core of our planet you can say goodbye to all life on this planet, yours included. 

Although it is not Earthquake related, I will come to that on a next post when addressing another kind of Natural Disaster we should prepare for.



At least, now, we know a little bit more about what's beneath our feet. With that knowledge, although basic, we can visualize and better understand the Earthquakes phenomenon, as well as the Volcanoes phenomenon. So, in the next posts we will quit the Inner Core and come back to the Surface and look at things on a human scale.

Until then, thank you for reading.
Mabuhay!

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