From sky charts to atomic clocks, time is a mysterious story that humans keep inventing

The standardisation and accuracy of human timekeeping has improved by leaps and bounds over the millennia – from tracing the stars, to the invention of timepieces, to the atomic ‘clocks’ of today. But for all our efforts, the concept of time, including whether it’s little more than an illusion of human psychology, remains deeply puzzling. In this interview with Robert Lawrence Kuhn for the PBS series Closer to Truth, the independent British physicist Julian Barbour endeavours to distinguish between our experience of time and its scientific underpinnings, including what has and hasn’t changed about our conception of time since we first looked to the skies to measure it.