The Compass

The Sun’s light defines what we mean by day and night, how we tell time and how we apportion our time, both consciously and unconsciously. The turning of the Earth that wheels us in and out of the Sun every 24 hours seeps into every aspect of our biology. In the final programme, Dava Sobel recalls the 25 days she spent as a human subject in a study of circadian rhythm. The lab was housed at Montefiore Hospital in the Bronx, NY, but it could have been anywhere, sealed and self-contained as it was. We’ll hear what happens when you are light deprived.To know the Sun is an age-old dream of humankind. For centuries, astronomers contented themselves with analysing small sips of sunlight collected through specialised instruments. They chased after eclipses that exposed otherwise hidden layers of the Sun’s substance, and they launched Earth and Sun-orbiting observatories to monitor our star from space. Today, several satellites ‘watch’ our star from outer space. In August 2018, NASA’s Parker Solar Probe, set off on a