What are the sources of earths internal heat?

Question

What are the sources of earths internal heat?

Answer 1

Magma which is molten rock and is always hot due to the earth rotating....I think thats right.  Also the sun provides alot of surface heat.

Answer 2

Volcano's.  Natural spring waters (over 100 degrees).  Probably many, many more than I can answer.

Answer 3

Geothermal pot of water on the stove.

Answer 4

The current theory is that the Earth's internal heat engine is powered by radioactive decay in the Earth's core.

Answer 5

the earth's core is the hottest part of the earth the magma is probably the coolest part below the earth's crust.

Answer 6

The main source of earth's internal heat is simply pressure caused by all the material around it.  The material is around it because of gravity, so in the final analysis the heat is due to gravity.

Radioactive decay adds some heat to the earth but compared to gravity, not much.