Science: The Sound of Security

Deerfield, in western Massachusetts, is a quiet New England village undisturbed since the raids of the French and Indian War. Its elm-sheltered main street is lined with early American houses; at least one resident still drives a horse and gig. But Deerfield is not so serene as it looks: at all too brief intervals, a thunderous boom splits the air, several hundred ancient windows rattle in their frames, and sometimes one breaks.

Like hundreds of other U.S. towns, Deerfield has become an unwilling part of a supersonic age. Jets from Westover Air Force Base, 25 miles to the south, blur past overhead—and...