We report the Earth's rate of radiogenic heat production and (anti)neutrino luminosity from geologically relevant short-lived radionuclides (SLR) and long-lived radionuclides (LLR) using decay constants from the geological community, updated nuclear physics parameters, and calculations of the β spectra. We track the time evolution of the radiogenic power and luminosity of the Earth over the last 4.57 billion years, assuming an absolute abundance for the refractory elements in the silicate Earth and key volatile/refractory element ratios (e.g., Fe/Al, K/U, and Rb/Sr) to set the abundance levels for the moderately volatile elements. The relevant decays for the present-day heat production in the Earth (19.9 ± 3.0 TW) are from 40K, 87Rb, 147Sm, 232Th, 235U, and 238U. Given element concentrations in kg-element/kg-rock and density ρ in kg/m3, a simplified equation to calculate the present-day heat production in a rock is (Formula presented.). The radiogenic heating rate of Earth-like material at solar system formation was some 103 to 104 times greater than present-day values, largely due to decay of 26Al in the silicate fraction, which was the dominant radiogenic heat source for the first ∼10 Ma. Assuming instantaneous Earth formation, the upper bound on radiogenic energy supplied by the most powerful short-lived radionuclide 26Al (t1/2 = 0.7 Ma) is 5.5×1031 J, which is comparable (within a factor of a few) to the planet's gravitational binding energy.
- beta decay
- radiogenic heat