Harrison Brown
The geochemist who saw that meteorites could reveal the age of the Earth, and set his student Clair Patterson on the task.
Key facts
- Born
- 1917
- Died
- 1986
- Nationality
- American
- Field
- Geochemist
Harrison Scott Brown worked on the separation of plutonium during the Second World War and afterwards became a professor at the University of Chicago and then the California Institute of Technology.
Brown realised that iron meteorites could provide a sample of the original lead of the Solar System. Their troilite contains lead but almost no uranium, so its lead has not grown since it formed. If that starting value were known, the age of the Earth could be calculated from the lead in Earth rocks. He gave the problem to his student Clair Patterson, who solved it in 1956 using the Canyon Diablo meteorite.
Brown also studied the abundances of the elements in meteorites, noted how the rare gases are depleted on Earth compared with the Sun, and helped to found the modern field of geochemistry. He brought together young scientists who became leaders in the study of meteorites and the Moon.
Later in life he wrote widely about the future of humanity, natural resources and the dangers of nuclear weapons, and served as foreign secretary of the National Academy of Sciences.