Research into 13th Century bishop’s theories about rainbows makes Nature Physics

Credit: Hannah Smithson

An interdisciplinary study of how a medieval bishop’s theories inspired modern thinking about colour conception and the rainbow has been published in the prestigious journal, Nature Physics.

The study, examining the work of Bishop Robert Grosseteste (c.1170-1253), stems from the Durham University-led Ordered Universe project, an investigation into medieval science involving researchers from the sciences, social sciences and arts and humanities.

The article was authored by Ordered Universe team members, Dr Giles Gasper and Professor Tom McLeish, of Durham University, and Dr Hannah Smithson, of the University of Oxford.

Robert Grosseteste was a medieval scholar whose investigations into the nature of light - De colore (On Colour), De iride (On the Rainbow), and De luce (On light) – provide a unique insight into the longer story of human understanding of natural phenomena.

Grosseteste moved away from the Aristotelian one-dimensional scale of seven colours existing between black and white, by noting that the colours can differ from black and white according to their place within a three-dimensional space.

In the De iride, Grosseteste notes that colour variation occurs within a rainbow, but also between rainbows depending on the purity of the medium – as occurs with differently sized water droplets – and depending on the angle of the sun which affects the light creating a rainbow.

Dr Hannah Smithson said: “Almost 800 years after he wrote them, reading Grosseteste’s treatises have prompted the exploration of a new co-ordinate system of colour.

“One of the most surprising things to discover was that, by formally modelling the colours that are produced in naturally occurring rainbows, we have shown that Grosseteste’s scheme is a perfectly valid way to navigate perceptual colour space with three independent variables, despite its unfamiliarity to modern eyes.”

Dr Giles Gasper added: “Reading of Grosseteste’s scientific treatises requires an interdisciplinary effort.

“Handwritten manuscripts, often damaged or quirky in their penmanship, are challenging to transcribe, using an evolving Latin language in which the precise meaning of the words is not easy to pin down.

“The subject matter is mathematical, and expressed in such economical language that it needs a wide range of disciplinary experts to unpack the texts in their full meaning.

Professor Tom McLeish, project member and also Durham’s Pro-Vice-Chancellor for Research, said: “Such collaboration yields dividends for humanities as much as it does for modern science, and is an important corrective to the common perception of science as a modern invention.”

To read the Nature Physics article click here.

More on the Ordered Universe project (principal investigator, Dr Giles Gasper, Department of History; co-investigator, Dr Hannah Smithson, Department of Experimental Psychology, University of Oxford) can be read here. The Ordered Universe Team’s edition, translation and analyses of the De colore treatise can be found here. Professor Tom McLeish’s recent book on the long story of science can be found here.