The Stefan-Boltzmann constant is a physical constant denoted by the symbol \sigma . It describes the power radiated by a black body in thermal equilibrium per unit area, proportional to the fourth power of its absolute temperature. The value of the constant is approximately 5.67 \times 10^-8 \, \textW/m^2\textK^4 . This constant is crucial in fields like astrophysics and climate science, as it helps calculate the energy output of stars, including our Sun, and the heat loss from Earth. It is named after physicists Josef Stefan and Ludwig Boltzmann, who contributed to its formulation.