A Short History of Nearly Everything

by Bill Bryson

Patterson began work on the project in 1948. Compared with Thomas Midgley’s colourful contributions to the march of progress, Patterson’s discovery of the age of the Earth feels more than a touch anti-climactic. For seven years, first at the University of Chicago and then at the California Institute of Technology (where he moved in 1952), he worked in a sterile lab, making very precise measurements of the lead/uranium ratios in carefully selected samples of old rock. The problem with measuring the age of the Earth was that you needed rocks that were extremely ancient, containing lead- and uranium-bearing crystals that were about as old as the planet itself – anything much younger would obviously give you misleadingly youthful dates – but really ancient rocks are only rarely found on Earth. In the late 1940s no-one altogether understood why this should be. Indeed, and rather extraordinarily, we would be well into the space age before anyone could plausibly account for where all the Earth’s old rocks went. (The answer was plate tectonics, which we shall of course get to.) Patterson, meanwhile, was left to try to make sense of things with very limited materials. Eventually, and ingeniously, it occurred to him that he could circumvent the rock shortage by using rocks from beyond Earth. He turned to meteorites. The assumption he made – rather a large one, but correct as it turned out – was that many meteorites are essentially left-over building materials from the early days of ...

Clair Patterson - dating earth to 4.55 billion years by studying meteors