Classic Thermodynamics Papers
(English Translations)
Boltzmann, L.
Boltzmann, L.
Carnot, N.L.S.
Carnot, N.L.S.
Clausius, R.
Clausius, R.
Fourier, J.
Fourier, J.
Kirchhoff, G. (1860). I. On the relation between the radiating and absorbing powers of different bodies for light and heat. The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science, 20(130), 1–21.
In the 1850s, German physicist Gustav Kirchhoff advanced our understanding of heat and light. His 1859–1860 paper, published in Monatsberichte der Königlichen Preussischen Akademie der Wissenschaften zu Berlin, introduced Kirchhoff’s Law of Thermal Radiation. This law states that, for a surface in thermal equilibrium, its absorptivity (how much radiation it absorbs) equals its emissivity (how much it emits) at a given wavelength. For opaque surfaces, this implies emissivity + albedo = 1, where albedo is the reflected fraction of radiation.
Kirchhoff’s work was groundbreaking, linking energy absorption and emission in thermodynamics, enabling spectral analysis in astronomy, and laying the groundwork for Max Planck’s quantum theory. Today, it’s vital in climate science, as albedo (e.g., of ice or forests) and emissivity drive Earth’s energy balance, influencing climate models and planetary temperature calculations.
This paper offers a window into 19th-century physics, revealing Kirchhoff’s rigorous approach. Though technical, it is a foundation for thermodynamics and climate studies. Pair it with modern resources for clarity, and explore our growing collection of classic thermodynamics papers for deeper insights.
Maxwell, J. C.
Maxwell, J. C
Planck, M.
Planck, M.
Stefan, J.
Stefan, J.
Wien, W.
Wien, W.
