Ernst Mach

Ernst Waldfried Josef Wenzel Mach was born on 18 February 1838 in Austria, and spent his career pulling apart assumptions older scientists took as gospel. His work on shock waves gave us the Mach number, the ratio that measures how fast something moves compared to sound. But his sharpest cut was philosophical: he tore into Newton's ideas of absolute space and time, arguing they were metaphysical baggage physics didn't need. That skepticism rippled through logical positivism and American pragmatism, and it planted seeds Einstein would harvest when he dismantled the same Newtonian framework in relativity. Mach died on 19 February 1916, a day after his seventy-eighth birthday, having cleared ground he never fully walked himself.