Scientist's Explanation of why Earth's Inner Core is so Hot (Comparable to that of the Sun's Surface) and Yet Does Not Melt

For many years, scientists have always been puzzled by the about Pluto-sized inner core orb of earth being made up of solid iron while being surrounded by a liquid outer core.

^{Source: Structure of the Earth Showing Different Layers}


If we are to travel about 6000KM down the earth's crust you would get to the solid inner core and would be greeted with incinerating temperatures of about 6,000C, give or take 500C roughly the same temperature to that of the Sun's surface.



^{Source: Image showing a cutaway portion of earth showing approximate distance to the inner core}

How did the core come to be that hot?

There are three main causes of these extremely high temperatures at the inner core:

1. The heat when the planet was formed and accreted which was still trapped inside it and not lost. This heat was as a result of collisions (pieces of matter that impacted each other) which formed the planet.
   The cooling process started after this formation.

2. As a result of friction necessitated by denser core material sinking to the center of the planet.

3. The heat formed by radioactive element decay not only uranium but also potassium and a few others which maintains these high temperatures.

The Mystery of The Solid Inner Core Demystified

The inner core of the Earth surface is same or even hotter( depending on different school of thoughts since the measurement is an approximation and not an exact science due to the vast distance involved and lack of equipment for precise measurement)than the
sun's surface but does not melt and instead, it remains in solid crystal form

The researchers from the Physics Department of KTH Royal Institute of Technology in Stockholm, Sweden has a theory on why that is so; which they published in their article earlier this Feb 2017, titled Stabilization of body-centered cubic iron under inner-core conditions.

The extreme temperatures of the inner core set all the molecules in motion in a phenomenon known as diffusion. This, at the atomic level, causes instability which results in the iron crystals turning into a liquid.
Some pieces of the crystal atomic structures slide off only to be reinserted back into the crystal.






This is like a magician quickly shuffling a deck of cards. Each atom leaves the pack (core) momentarily only to be placed back making a solid deck of cards at any moment.


Knowing that and other features of the way our planet is structured can help us make relevant forecasts for what might occur to it in the future.

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