If the temperature at the edge of a solar granular cell is 5500 K and the center of the cell is 300 K hotter, what will be the ratio of fluxes of energy out of these two regions of the Sun (i.e., brightness contrast)?

Question

Quizplus · Accepted Answer

The flux of energy radiated by a surface (in this case, parts of the Sun) is given by the Stefan-Boltzmann law, which states that the energy radiated per unit area is proportional to the fourth power of the temperature (in Kelvin). Therefore, if the center of the cell is 300 K hotter than the edge (5500 K + 300 K = 5800 K), the ratio of the fluxes can be calculated as (5800/5500)^4, which gives a value slightly greater than 1, indicating the center is brighter. The exact calculation gives a factor close to 1.24, making the center brighter than the edge by this factor.

If the Temperature at the Edge of a Solar Granular