Basically, I was thinking of something in which one has a very small ‘target’, and a much larger (but still tiny relative to the whole system) ‘source’, both close to black body, and these objects at the two foci of a giant ellipsoidal reflector.
It seems that if the started at the same temperature, the source would radiate more than the target due to its larger surface area,and that radiation would hit the target, resulting in a temperature difference.
The amount of the source’s radiation that will actually reach the target is the same as the target’s emitted radation. Because the source is larger, there are steep angles it can emit at that do not pass through the target and only return to itself.
It looks to me like you’re tacitly assuming genuinely pointlike sources and targets when you say “that radiation would hit the target”, but then going back and reversing that assumption when you say the source would radiate more. The surface of the source is not exactly at the focal point, and so radiation from it does not necessarily pass exactly through the other focal point.
Which specific arrangement do you have in mind, and why would it break thermodynamics?
Basically, I was thinking of something in which one has a very small ‘target’, and a much larger (but still tiny relative to the whole system) ‘source’, both close to black body, and these objects at the two foci of a giant ellipsoidal reflector.
It seems that if the started at the same temperature, the source would radiate more than the target due to its larger surface area,and that radiation would hit the target, resulting in a temperature difference.
The amount of the source’s radiation that will actually reach the target is the same as the target’s emitted radation. Because the source is larger, there are steep angles it can emit at that do not pass through the target and only return to itself.
It looks to me like you’re tacitly assuming genuinely pointlike sources and targets when you say “that radiation would hit the target”, but then going back and reversing that assumption when you say the source would radiate more. The surface of the source is not exactly at the focal point, and so radiation from it does not necessarily pass exactly through the other focal point.
OHHHHHHHH...… I get it. Thank you.