Steel expands 11 parts in a million for each 1 ^\circ \rm C change. Consider a 40,000-{\rm km} steel pipe that forms a ring to fit snugly all around the circumference of the Earth. Suppose people along its length breathe on it so as to raise its temperature 0.80^\circ C. The pipe gets longer. It also is no longer snug. How high does it stand above ground level?