What is the real reason for the temperatures at the core of the earth?

Question

I used to think it was the gravitational force of the earth, but I just read that it is from the decay of radioactive material? What do you think?

Please...educated answers only.

Answer 1

There are three main sources of heat in the deep earth: (1) heat from when the planet formed and accreted, which has not yet been lost; (2) frictional heating, caused by denser core material sinking to the center of the planet; and (3) heat from the decay of radioactive elements.

Answer 2

Radioactive decay of K-40 (the radioactive isotope of potassium) is the primary source of heat in Earth's interior. Most people (apparently including some geologists) think only of Uranium and Thorium as the radioactive elements in the Earth that are responsible for internal heat. But there is considerably more K in the Earth than U or Th - even in the mantle. And recent research has found that it is possible for K to form an alloy with Fe under very high pressures and could account for as much as 0.1% of the core, which, given the ralative abundance of K-40, if distributed throughout the core, would be responsible for 1/5 of Earth's internal heat. So, combined with the K-40 in the mantle, which is the most voluminous part of Earth's internal structure, this radioactive decay energy accounts for at least half, if not most, of Earth's internal heat. Certainly, there is some heat left over from Earth's formation, and from gravitational energy, and perhaps the relative ratios of these heat sources are still under investigation.

Answer 3

justask23,

There are two reasons for the internal heat of the earth. One of them is indeed the decay of radioactive isotopes, which may seem insignificant considering how small a concentration they have in the earth as a whole. However, nuclear decay processes are highly exothermic, and the decay of even a little bit of material can produce a lot of heat.

The other is simply the latent heat leftover from the formation of the earth. The earth cooled from a ball of very hot, interstellar material. Since heat must conduct to the outside of an object before being released, much of this original heat is still trapped in the core and mantle of the earth and is slowly dissipating to this day.

Answer 4

The "real reason" is thermonuclear decay of radioactive elements, mostly uranium, thorium and potassium. Although potassium is far more abundant than uranium or thorium, the amount of heat generated when potassium decays into argon is trivial compared to uranium or thorium. The amount of heat is determined according to Einstein's equation E=mc^2, which relates energy (E) to mass (m) with the constant the square of the velocity of light (c^2).

Answer 5

Yes it is the decay of radioactive materials. Well that is the current widely accepted notion. I don't know how they determined that though.

Answer 6

Its from the pressure of gravity, the earth and so on... the crust of the earth is very small.. the core is large.. it has to be made that way or it wouldn't spin at the rate it does, with holo core or cold core it wouldnt react to the forces around us.... the core of the earth also has to be molten because all energy grounds.

Answer 7

well...all that pressure affects temperature.