James Clerk Maxwell

James Clerk Maxwell (1831–1879) was a soft-spoken Scottish genius who united electricity, magnetism, and light into a single set of equations. Many physicists rank him just below Newton and Einstein — and he managed it all in a short life of only 48 years.

An idea for the ages

Maxwell took every known rule of electricity and magnetism — including Faraday's law — and stitched them into four compact equations. Then he noticed something staggering: his equations predicted waves that travel at exactly the speed of light. Light, he realised, is an electromagnetic wave. Radio, radar, WiFi, and microwaves are all children of that single insight.

To prove that any colour can be built from red, green, and blue, Maxwell had a tartan ribbon photographed three times through coloured filters, then projected them together — creating the world's first colour photograph. It's the same trick your phone screen uses today. He was also famously modest and kind, writing playful poetry, riding his horse while thinking through equations, and quietly caring for his sick wife for years while doing some of his greatest work.