Shadow of Flight

As it turns out, at any altitude the Falcon's shadow will be 195 square feet. Because of the extreme distance of the sun, the photons' paths are effectively parallel when they meet the glider.

The nit-pickers out there will recognize that this solution is theoretically not completely correct. Because the sun is actually a finite (though very large) distance away, the shadow should be slightly larger than the glider. But because the sun isn't a point, but a large sphere, light emits from many sources. And since these sources cover an area larger than the glider, the shadow should be smaller than the glider.

Which is correct? Both are: the glider's umbra, the part of the shadow where none of the sun's rays hit, is smaller. The glider's penumbra, the part of the shadow where some, but not all of the sun's rays are blocked by the glider, is larger. And both of these answers ignore the fact that photons don't necessarily travel in straight lines. But that's for another puzzle.