From Lawrence of Arabia to Star Wars via tales of intrepid adventurers traversing lonely sandswept landscapes, deserts have always had a powerful pull on the popular imagination.

But if a desert is full of sand, where did all that sand come from in the first place? That’s what CrowdScience listener Andy wants to know, so presenter Caroline Steel heads off into the dunes to try and find out.

Along the way she’ll be wondering what a desert is anyway and whether it’s always sandy, as well as tracing the flow of material across the huge, ever-shifting sand seas of the Sahara.

From deserts fed by sand from mountains thousands of kilometres away, to dunes migrating across the entire continent of Africa, we’ll discover how sand has just the right properties to be carried along by the wind.

We’ll also explore how the sand in every desert has a unique fingerprint, and find out how fish bones in the Sahara tell the story of its lush, green past.

Contributors:
Dr Jo Nield, University of Southampton
Dr Andreas Baas, Kings College London
Dr Andrea Zerboni, University of Milan

Presented by Caroline Steel
Produced by Ben Motley for the BBC World Service

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