Particle physicists may freeze a second, open it up, and explore its dappled contents like surgeons pawing through an abdomen, but in real life, when events occur within thousandths of a second, our minds cannot distinguish past from future.

One measure of twentieth-century time is the supersonic three and three-quarter hours it takes the Concorde to fly from New York to Paris, gate to gate. Other measures come with the waits on the expressways and the runways.

Nanosecond precision matters for worldwide communications systems. It matters for navigation by Global Positioning System satellite signals: an error of a billionth of a second means an error of just about a foot, the distance light travels in that time.

James Gleick Quotes