An empty bottle sits on a windowsill next to a closed window inside a house. The outside and the house are in thermal equilibrium. Yet, the side of the bottle OPPOSITE the window has a higher temp then the side touching the window. How can this be? (Assume nothing is touching the bottle except the windowsill) Well, this is what I reasoned so far. There is only 3 ways that heat can be transferred, conduction, convection, and radiation. There is no conduction that is heating the hotter side because there is nothing touching it. It can't be convection b/c the room is in thermal equilibrium with the outside. It has to be the fact that something in side the room is radiating energy onto it. Does this make sense? Any other ideas?