‘Tracing the origin and the evolution of Earth’ outlines some of the key chapters in the history of the Earth where radioactivity and radiation play a critical role. It starts with the Big Bang, nuclear fusion, and the evolution of galaxies, stars and our solar system. The age of the Earth has long been disputed, but uranium-lead dating has been used to date rocks in Western Australia to 4.4 billion years old. It has also allowed dating of cyanobacteria and the first complex cells. Other techniques such as synchroton radiation and neutron activation analysis have allowed palaeontologists and other scientists to derive detailed information of the Earth's history from the fossil record.