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I found one very interesting physics problem but I have no idea how to solve it.

Lets say we have a star with radius R and the surface temperature T. Now we wish to know, what is the ratio between the total power output of the star and the power that the distant planet recieves from that star. The planet has a radius r and the distance between the center of the objects is d. We idealise the problem and say that both object have e=1.

I know that the trick is in the Stefan's law. I can calculate the power output of the star by

P=Stefan's constant*area of a spheare of radius R*temperature of star T on the 4th power,

now the funny thing is how can you calculate how much of that power is intercepted by the planet?

Any help would be apprichiated.

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# Black body radiation, need help

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