gen-explain-luminosity-and-the-stefan-boltzmann-law-as-you-would-6cd1

Explain luminosity and the Stefan-Boltzmann law as you would to a capable student, in 3-4 sentences.

Luminosity is the total amount of energy a star radiates per second across all wavelengths—essentially, it's the star's total power output. The Stefan-Boltzmann law tells us that luminosity depends on two factors: a star's surface area (which scales with radius squared) and its surface temperature raised to the fourth power, expressed as L = 4πR²σT⁴. This means that temperature is extremely important—if you double a star's temperature, its luminosity increases by a factor of 16, while doubling the radius only increases luminosity by a factor of 4. This relationship explains why hot, blue stars can be incredibly luminous even if they're not particularly large, while cool, red stars must be enormous (like red giants) to achieve high luminosity.