Why is the Sky Blue? by John M. Scanlon, M.D.
There seem to be two kinds of humans who regularly ask seemingly simplistic questions. One is the young child; the other is the genius. “Why is the sky blue, Daddy?” has become cliché for a banal, obvious query. I suspect the annoyance for adults is, in large part, because most of them don’t actually know the answer. Profound truths are sometimes uncovered during the process of answering simple-sounding questions. True, it took very special circumstances for Sir Alexander Fleming to wonder why bacteria didn’t grow around the moldy edges of his Petrie dish. He had to have a laboratory, agar plates, bacteria and yeast together in one place. But Fleming’s question was profoundly simple, and penicillin was the answer. During the last half century, basic questions have been raised about obvious natural phenomena. Answers have led to startling advances in knowledge. Someone wondered why woodpeckers don’t suffer from serious headaches or sustain brain damage hammering their bills on dead trees all day. The Family picidae characteristically slam sturdy beaks into wood searching for wriggling food. In spring, most members of this
family tap out love messages in the same drumming manner. Such repetitive head trauma should render older woodpeckers punch drunk, with Swiss cheese for brains. It turns out the woodpecker’s skull, its neck muscles and spinal ligaments are mar vels of natural energy-dissipating engineering. The brain is cushioned in a unique way using spinal fluid. The skull’s supporting muscles and tendons provide dynamic counterbalance to the endless forward jackhammer beak thrusts. Appreciation for this physiology led to practical application for safety helmet design and other devices used in sports and automotives. This important research is on-going. Another basic question was how a hummingbird’s wings can rotate so rapidly that the shoulder joint 45