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.

From the spontaneous combustion of marsh gas to the lightning sparks emitted by crushed sugar, Professor Sella finds there's more to light than ever meets the eye.