Snapshots of life’s dancers

Time, the physicist John Wheeler famously said, is nature’s way of preventing everything from happening at once. Yet our instincts are to squish events back into timeless superposition. From the simultaneous comic-strip of the Bayeux Tapestry to the summed statistics of football matches, we tend to convert complex, dynamic processes into static images and averages. Technologies that capture temporal change are relatively recent, and Louis Daguerre’s earliest photographs of street scenes, in which ephemeral pedestrians vanish during the long exposure, offer a metaphor for how time-averaging can wash away crucial details.