Blackbody Radiation

The theory of black bodies, suggested by Kirchhoff, posits that a body absorbing all light and reflecting none, known as a black body, when heated, emits all wavelengths of light. This led to significant advancements in understanding light and temperature distribution across the spectrum.
 Gustav Robert Kirchhoff Germany 1860 Blackbody Radiation

The theory of black bodies, suggested by Kirchhoff, posits that a body absorbing all light and reflecting none, known as a black body, when heated, emits all wavelengths of light. This led to significant advancements in understanding light and temperature distribution across the spectrum.