Hi, having a bit of trouble with a basic question on thermal radiation. If you take a slab of material that has the characteristics of a blackbody and heat it to temperature where its only emitting in the IR, then its temperature will slowly decrease as the heat is rejected (assuming no incoming radiation). If you take the same slab and drill a series of holes partially into one surface you are effectively increasing the surface area of the slab. However the rate of temperature decrease is the same because flux through the hole apertures cannot change otherwise it would violate the second law. I think I understand the mechanism of this as any increase in surface area is compensated for by the fact that all these surfaces are now absorbing radiation emitted by the opposing inner wall surfaces. Is this correct? I'm assuming the internal walls are perfectly smooth BTW. My problem comes when I consider a slab made of some IR reflective material like gold. In this case the internal surfaces are highly, though not perfectly, reflective for IR. So the absorption of the inner walls should be reduced. What then is the mechanism that prevents this structure from breaking the second law? I'm sure I'm overlooking something obvious here. Thanks!