The Guamanian memorial stands proudly in Memorial Row on Wake Island. The delicately engraved plaque has been obscured by a well-intentioned but misguided attempt to mitigate weathering by applying a protective coating. One has to squint and shift a bit until the light hits it just right to make out the names. Context is not offered: the casual observer might wonder who they were and how they fit in to the saga of World War II on Wake Island....

A few weeks ago I heard a Radio Lab podcast about coral that got me to thinking about time and change (“The Times They Are a-Changin’”) Scientists dissecting coral shells find gray bands similar to tree rings that represent annual growth stages. Under water, coral grows an external skeleton in time with the cycles of light, temperature, and tides. In a living coral, the space between the annual growth bands contains faint lines that number...