How is the core of the Earth kept hot?

In summary, the Earth's core is not directly heated by radioactivity within the core itself, but rather by energy from radioactive decay in the mantle and crust. This accounts for up to 90% of the heat, with the remaining 10% coming from other sources such as tidal forces from the Moon and Sun. Tidal push and pulls are considered part of the 5 to 10% of heat generated by friction caused by gravity.
  • #1
Forestman
212
2
I know that the mantel of the Earth is kept hot by radioactivity, but is this also true for the core?
 
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  • #2
Yes.

Addendum. Most of the radioactivity is in the crust and the mantle; but this is still generating heat which contributes to keeping the core hot. For lots more detail see Probing Question: What heats the Earth's core? at physorg.com

So the core is not being kept hot by radioactivity in the core; the energy from decay in the mantle and crust is more important. I had to look this up also.
 
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  • #3
Thanks sylas.
 
  • #4
does the Earth gain significant heat from the moon and the suns tidal pull?
 
  • #5
The link that sylas provided list 4 sources of heat within the earth.

Up to 90% of the heat is from radioactive decay.
About 5 to 10% is from friction caused by gravity.
About 5 to 10% is residual left over from the original formation of earth.
A small amount is latent heat released when molten materials turn into solids.

As I understand it, tidal push and pulls are part of the 5 to 10% gravity friction portion.
 

1. How is the core of the Earth kept hot?

The core of the Earth is kept hot through a process called radioactive decay. This is the breakdown of radioactive elements, such as uranium and thorium, which release heat as they decay. This heat is then trapped and maintained by the layers of the Earth above the core.

2. What role does pressure play in keeping the Earth's core hot?

The immense pressure at the Earth's core also plays a crucial role in keeping it hot. As the core is under immense pressure from the weight of the layers above, it prevents the heat from escaping and allows it to build up, maintaining the high temperatures in the core.

3. How does the Earth's magnetic field contribute to the heat of the core?

The Earth's magnetic field is generated by the spinning and movement of the liquid outer core. This process, known as the geodynamo effect, generates heat, which contributes to keeping the core hot. Without this heat, the Earth's magnetic field would weaken and eventually disappear.

4. Can the core of the Earth ever cool down?

The core of the Earth is estimated to have been hot since the planet's formation over 4 billion years ago. While the rate of heat production may decrease over time, it is unlikely that the core will ever completely cool down. The process of radioactive decay and pressure will continue to generate heat, keeping the core hot.

5. What would happen if the Earth's core were to cool down?

If the Earth's core were to significantly cool down, it would affect the entire planet. The Earth's magnetic field would weaken, leading to increased exposure to cosmic radiation. This could also result in a loss of the protective ozone layer, causing harmful effects on life on Earth. Additionally, the cooling of the core could also disrupt the Earth's tectonic plates, leading to earthquakes and volcanic eruptions.

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