Where does the Earth's heat come from?

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In summary, Core formation was also important. Descent of iron and other elements to the centre of the planet converted gravitational potential energy to thermal energy. There is also ongoing release of latent heat as the solid inner core slowly grows at the expense of the fluid outer core. Other minor contributions include input from tidal flexing and possibly certain mineral phase changes.
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ISamson
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Hello.

I have an 'Earth and Space Science' topic test tomorrow.
Heavily revising, I come across a section that will be in the test: geothermal energy.
It works by cold water being pumped down in pipes, underground and then back up, hot, in form of steam to spin turbines and generate electricity.
Now to the question. Where does Earth's heat originally come from? It forms in nuclear reactions like in the Sun or the Sun itself?
Thank you.
 
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ISamson said:
originally come from?
"Accretion" is more than a little likely the expected answer within the/a geothermal context.
 
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I like Serena said:
Hi ISamson!

See https://en.m.wikipedia.org/wiki/Earth's_internal_heat_budget :
The flow of heat from Earth's interior to the surface is estimated at 47 terawatts (TW)[1]and comes from two main sources in roughly equal amounts: the radiogenic heat produced by the radioactive decay of isotopes in the mantle and crust, and the primordial heat left over from the formation of the Earth.[2]

Thank you! Just what I needed.
So the radioactive decay powers the Earth's heat along with the heat left from the formation of the Earth. So the Earth inside is radioactive!?
 
  • #5
ISamson said:
Thank you! Just what I needed.
So the radioactive decay powers the Earth's heat along with the heat left from the formation of the Earth. So the Earth inside is radioactive!?
Yup.

From the same wiki article:

The radioactive decay of elements in the Earth's mantle and crust results in production of daughter isotopes and release of particles and heat energy, or radiogenic heat. Four radioactive isotopes are responsible for the majority of radiogenic heat, uranium-238 (238U), uranium-235 (235U), thorium-232 (232Th), and potassium-40 (40K).[14] Due to a lack of rock samples from below 200 km depth, it is not possible to do a simple radiogenic heat estimate of known radioactive isotope concentrations in rock throughout the whole mantle.[14] For the Earth's core, geochemical studies indicate that it unlikely to be a significant source of radiogenic heat due to an expected low concentration of radioactive elements.[2]
 
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Core formation was also important. Descent of iron and other elements to the centre of the planet converted gravitational potential energy to thermal energy. There is also ongoing release of latent heat as the solid inner core slowly grows at the expense of the fluid outer core. Other minor contributions include input from tidal flexing and possibly certain mineral phase changes.
 

1. Where does the Earth's heat come from?

The Earth's heat primarily comes from two sources: the Sun and the Earth's core. The Sun constantly radiates heat and light towards the Earth, warming the planet's surface. The Earth's core also produces heat through the process of radioactive decay.

2. How does the Earth's core produce heat?

The Earth's core is mostly made up of iron and nickel, which are both radioactive elements. As these elements decay, they release energy in the form of heat. This process is estimated to generate about half of the Earth's internal heat.

3. What is the role of convection in the Earth's heat?

Convection plays a crucial role in the distribution and transfer of heat within the Earth's interior. As the Earth's core produces heat, the surrounding molten rock becomes less dense and rises towards the surface, carrying the heat with it. This creates convection currents that circulate heat throughout the Earth's mantle and crust.

4. Does the Earth's heat change over time?

Yes, the Earth's heat is constantly changing. The amount of heat coming from the Sun can vary due to changes in solar activity, and the Earth's core may also cool down over time as radioactive elements decay. Additionally, geological events such as volcanic eruptions can release large amounts of heat into the Earth's surface.

5. How does the Earth's heat contribute to plate tectonics?

The Earth's internal heat is a major driving force behind plate tectonics, the movement of the Earth's crustal plates. The convection currents within the Earth's mantle cause the plates to move, which can result in geological events such as earthquakes and volcanic eruptions. Without the Earth's internal heat, plate tectonics would not occur and the Earth's surface would look very different.

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