One chemist measured the Earth's exact age using a meteorite's lead

Clair Patterson compared lead isotopes in a 4.5-billion-year-old meteorite to lead in modern rocks and calculated Earth's age to within 1%: 4.55 billion years, a figure barely revised since. Getting a clean reading meant inventing ultra-clean lab techniques, which later let him show how much lead pollution industrial society had added to the planet — work that helped get lead banned from gasoline.

— Clair C. Patterson, Age of Meteorites and the Earth — Geochimica et Cosmochimica Acta, 1956