On the BBC Radio 4 “Listen Again” online service: Spooklights…

“Folk tales are full of fleeting phenomena like will o’ the wisps, faint glows that must have spooked our ancestors. But these days, it’s just about impossible to escape the omnipresent illumination of modern life, and these evocative spooklights have vanished like ghosts. Chemist Andrea Sella explores the science of lights so dim, they can be witnessed only in complete darkness.”