The blackbody radiation curve has an interesting property: the ratio of differential power emitted at any two light frequencies is a function of purely the temperature of the blackbody. Also, since the power in both frequencies goes down as the square of the distance to the blackbody, this ratio is independent of the distance.
This fact is often used in stellar astrophysics to estimate the 'color temperature' of stars from the continuum part of the spectrum, and therefore the total emitted power. Comparing to the power we receive, this is a direct measure of the distance to the star.
The blackbody radiation curve has an interesting property: the ratio of differential power emitted at any two light frequencies is a function of purely the temperature of the blackbody. Also, since the power in both frequencies goes down as the square of the distance to the blackbody, this ratio is independent of the distance.
This fact is often used in stellar astrophysics to estimate the 'color temperature' of stars from the continuum part of the spectrum, and therefore the total emitted power. Comparing to the power we receive, this is a direct measure of the distance to the star.