Happy birthday to mathematician Dame Mary Cartwright! Here’s more from the UK Science Museum:

In 1938 with Europe at the brink of war, the Radio Research Board of the British Government’s Department of Scientific and Industrial Research sent out a memorandum to the London Mathematical Society asking for help with equations related to radio engineering. Dr. Mary Cartwright was a mathematics lecturer at Girton College, Cambridge. She had already created Cartwright’s theorem solving a problem posed by J. E. Littlewood  and was researching function theory. She responded to the memorandum’s call and took on the challenge of working with her more unfamiliar differential equationsin collaboration with Littlewood.

Although they did not supply the answer in time, they mathematically explained the radio waves’ erratic behaviour redirecting the engineers’ attention who ultimately harnessed radar technology, while observing a totally unknown scientific field at the time: chaos theory. She later remarked on the divide between pure and applied Maths that ‘a number of major developments in pure Maths were first thought out in terms of real-world situations.’

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