Radiogenic heat

Radiogenic heat is thermal energy released when unstable atomic nuclei decay. It warms planetary interiors and contributes to Earth’s geothermal energy.

Radioactive decay: The spontaneous transformation of unstable atomic nuclei into more stable nuclei, emitting particles or radiation. Radiogenic heat is the portion of decay energy that becomes thermal energy.
Isotope: One of several forms of an element, distinguished by its number of neutrons. Radioactive isotopes are the nuclei whose decay produces radiogenic heat.
Geothermal energy: Usable thermal energy extracted from Earth’s interior or near-surface rocks and fluids. Radiogenic heat is one source of the subsurface warmth exploited by geothermal systems.
KamLAND: A Japanese liquid-scintillator experiment that detects antineutrinos from nuclear reactors and Earth’s interior. Its geoneutrino observations constrain the amount of radioactive heat produced inside Earth.
Alpha decay: A nuclear decay process in which a nucleus emits a helium-4 nucleus. Alpha particles deposit energy as they slow within surrounding rock.
Potassium-40: A naturally occurring radioactive isotope of potassium with a half-life of about 1.25 billion years. Its long-lived decay contributes heat in Earth’s crust and mantle.
Earth's heat budget: The balance of heat generated, stored, and lost within Earth. Radiogenic production is a major term in estimates of Earth’s internal heat supply.
Borexino: An underground Italian neutrino experiment that measured solar neutrinos and geoneutrinos. Its geoneutrino data help estimate Earth’s radiogenic heat output.
Beta decay: A nuclear decay process in which a neutron and proton change into one another, emitting a beta particle and a neutrino or antineutrino. Beta particles and accompanying radiation transfer decay energy into planetary material.
Uranium-238: A naturally occurring uranium isotope with a half-life of about 4.47 billion years. Its decay chain has generated heat throughout much of Earth’s history.

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