Stefan-Boltzmann law
Blackbody emission formula
The Stefan-Boltzmann law states that the total energy radiated by a black body is proportional to the fourth power of its absolute temperature.
This principle from thermodynamics explains why hotter objects radiate dramatically more energy—double the temperature, and radiation increases sixteenfold.
The law is fundamental to astrophysics, allowing scientists to calculate the luminosity of stars from their surface temperatures.
Perfect thermal emitter
- thermal radiationElectromagnetic waves from temperature
- emissivityThermal radiation ratio
- irradianceIncident power per area
- absorptivityFraction of light taken in
electromagnetic radiation · infrared · intensity · transmissivity · reflectivity · radiant energy
Equal temperature throughout system
- heat transferMovement of thermal energy
- entropyQuantified chaos in systems
- energy densityStored power per unit
- energy balanceIntake versus expenditure ratio
Star's light-emitting surface
- main sequenceStable stellar burning phase
- red giantAged star with cooled, expanded envelope
- white dwarfExhausted star's compact corpse
- supernovaExploding massive star
Eighteenth Greek letter
- proportionalityScaling relationship between quantities
- surface areaMeasure of outer boundary
- exponentSuperscript showing power
- calculationMathematical problem-solving process
blackbody
Perfect thermal emitter
- thermal radiationElectromagnetic waves from temperature
- emissivityThermal radiation ratio
- irradianceIncident power per area
absorptivity · electromagnetic radiation · infrared · intensity · transmissivity · reflectivity · radiant energy
thermal equilibrium
Equal temperature throughout system
- heat transferMovement of thermal energy
- entropyQuantified chaos in systems
- energy densityStored power per unit
energy balance · cooling rate · quantum mechanics · Boltzmann
photosphere
Star's light-emitting surface
- main sequenceStable stellar burning phase
- red giantAged star with cooled, expanded envelope
- white dwarfExhausted star's compact corpse
sigma
Eighteenth Greek letter
- proportionalityScaling relationship between quantities
- surface areaMeasure of outer boundary
- exponentSuperscript showing power
- heatheat transfer, thermal energy, heatwave, radiation, convection
- Formulaschemical formula, quadratic formula, empirical formula, area formula, volume formula
- Heat Scienceheat transfer, heat capacity, heat flow, specific heat, latent heat
- Radiometryradiance, radiant energy, irradiance, radiometer, fluence
- thermodynamicsentropy, enthalpy, heat transfer, free energy, heat capacity
- heat transferconduction, convection, heat flow, heat transfer, conductors