Transcript: The Stephan-Boltzmann Law allows us to understand the state of stars with the same spectral type as the Sun but with very different luminosities. In this case the scaling reduces to radius going as the square root of luminosity. There are stars the same color as the Sun with 100 thousand times the Sun’s luminosity. By the Stephan-Boltzmann Law these stars must be three hundred times the size of the Sun. Conversely, there are stars the same color as the Sun with one-ten thousandths of the Sun’s luminosity, and these stars must be one hundredth the size of the Sun. Even without being able to measure stellar diameters directly we can use the physical scaling of the stellar model applied by the Stephan-Boltzmann Law to understand the true size of stars.