Radioactivity as a Tool for Knowledge
Editorial review 2026
After the discovery of radioactivity by Marie Curie, radioactive sources enabled Ernest Rutherford and other researchers to carry out the first explorations of the atomic nucleus. Since then, the applications of radioactivity have multiplied and have become irreplaceable sources of knowledge, making it possible to trace atoms and molecules with extreme sensitivity.
The great variety of radioactive elements and the wide range of their decay periods, which can extend from a few minutes to several billion years, allow radioactivity to be used in virtually every field.
In biological research, short-lived radioactive tracers such as fluorine-18 and phosphorus-32 are widely used. Iodine-123 allows the diagnosis of thyroid diseases through scintigraphy.
Carbon-14, with a half-life of 5,700 years, revolutionized archaeological research because it makes it possible to date objects and sites up to approximately 40,000 years old. Other radioactive methods (such as potassium-argon ratio analysis) are used for much older periods.
Radioactivity is also present in Earth and environmental sciences. Uranium, potassium, and rubidium have helped determine the age of the Earth more precisely. Climatologists measure the amount of beryllium-10 produced by cosmic rays in the atmosphere and stored in polar ice: its abundance depends on solar activity. Oceanographers can use carbon-14 measurements in the oceans to reconstruct the pathways of ocean currents.
Chauvet Cave rhinoceros dated using the carbon-14 method, which earned the 1960 Nobel Prize to the American physicist and chemist Willard Libby (right). © Chauvet Cave
Physicists have developed instruments capable of detecting radiation emitted by radioactive atoms and by other sources such as cosmic rays coming from space. Since the time of Marie Curie and Ernest Rutherford, numerous detectors of extraordinary sensitivity have been developed, capable of observing the decay of a tiny nucleus or the impact of an X-ray or gamma ray.
The discovery of radioactivity led to the discovery of the atomic nucleus and to the development of nuclear physics. As the first step in the exploration of the infinitely small, it eventually gave rise, through large particle accelerators, to a new discipline: particle physics. CERN Courier describes the history of these two disciplines in France in an excellent article: The Rise of Particle Physics in France, by Ursula Bassler and Denis Guthleben.
SUMMARY OF THE CHAPTER AND TOPICS COVERED
– Research on the nucleus – GANIL Accelerator
– Detection tools – Detection principles. Ultra-sensitive detection. Detectors. Geiger counters.
– Dating methods – Dating techniques: Carbon-14, the age of the Earth.
– Markers and tracers – Radioactive spies in infinitesimal quantities.
– Earth sciences – Oceanography, climatology.
– Gamma-ray astronomy – Exploration of space and its radiation.