Knowra Earth's internal heat budget Earth's internal heat budget Earth's internal heat budget accounts for heat generated or retained within the planet and heat escaping through its surface. Its sources include radioactive decay and leftover heat from Earth's formation.
Radiogenic heat production : Heat released by radioactive decay of unstable isotopes within Earth. Decay of uranium, thorium, and potassium supplies a major ongoing internal heat source.
Uranium-238 : A long-lived radioactive isotope of uranium that decays through a chain of daughter isotopes. Its decay chain contributes radiogenic heat over billions of years.
Geoneutrino : An antineutrino produced by radioactive decay inside Earth and detected at the surface. Geoneutrino measurements offer a direct constraint on radiogenic heat production.
Bulk silicate Earth : The composition of Earth's mantle and crust considered together, excluding the core. Its uncertain potassium, uranium, and thorium abundances affect estimates of radiogenic heat.
Primordial heat : Heat retained from Earth's formation, including accretion, impacts, and early differentiation. This inherited heat remains in Earth's interior as it cools over geological time.
Thorium-232 : A long-lived radioactive isotope that decays through a chain ending in lead-208. Its decay is another persistent source of heat within Earth.
Geodynamo : The process by which motion in Earth's liquid outer core generates its magnetic field. Core heat loss and compositional buoyancy help sustain the motions driving the geodynamo.
Geoneutrino detection : The measurement of antineutrinos from radioactive decays within Earth. Existing detections constrain, but do not yet precisely determine, the radiogenic share of heat.
Mantle convection : The slow circulation of solid mantle driven by temperature and density differences. Convection transports internal heat toward the surface and helps power plate tectonics.
Potassium-40 : A radioactive isotope of potassium that decays by electron capture and beta emission. Its abundance and decay contribute to estimates of Earth's radiogenic heat.
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