Past exam of the short options paper shared by Prelims and Parts A and B of the physics course of the University of Oxford / 2016 / S29 / 1 / 4 / a / Solution

The Moon's mean equatorial temperature near 206 K is well below the approximately 270 K global effective radiative temperature. The surface has a large day-night range and finite thermal inertia; $⟨T^4{⟩}^{1/4}$ exceeds $⟨T⟩$, so comparing those two differently averaged quantities as though they were equal is invalid. The discrepancy need not imply a missing atmospheric greenhouse effect on an airless Moon.