Sir Michael James Lighthill FRS FRAeS[3] (23 January 1924 – 17 July 1998) was a British applied mathematician, known for his pioneering work in the field of aeroacoustics[4][1][5][6][7] and for writing the Lighthill report in 1973, which pessimistically stated that "In no part of the field (of AI) have the discoveries made so far produced the major impact that was then promised", contributing to the gloomy climate of AI winter.

Lighthill's early work included two-dimensional aerofoil theory, and supersonic flow around solids of revolution.

In addition to the dynamics of gas at high speeds, he studied shock and blast waves and introduced the squirmer model.

Lighthill founded the Institute of Mathematics and its Applications (IMA) in 1964, alongside Professor Sir Bryan Thwaites.

Lighthill's report, which was published in 1973 and became known as the "Lighthill report," was highly critical of basic research in foundational areas such as robotics and language processing, and "formed the basis for the decision by the British government to end support for AI research in all but two universities",[17] starting what is sometimes referred to as the "AI winter".

[18] In 1983 Lighthill was awarded the Ludwig Prandtl Ring from the Deutsche Gesellschaft für Luft- und Raumfahrt (German Society for Aeronautics and Astronautics) for "outstanding contribution in the field of aerospace engineering".

He died in the water in 1998 when the mitral valve in his heart ruptured while he was swimming round the island of Sark, a feat which he had accomplished many times before.