Early 20th-century radiometric dating established that Earth is more than four billion years old [1].

This shift in understanding was critical because it replaced biblical and empirical age estimates with a verifiable scientific method. By providing a concrete timeline for planetary formation, these findings allowed researchers to understand the slow processes of geological change and biological evolution.

According to a documentary produced by the French public service broadcaster ARTE, the transition occurred during the early 1900s [1]. Before the adoption of radiometric techniques, estimates of the planet's age were often based on religious texts or limited empirical observations that underestimated the time required for Earth's features to form.

Radiometric dating works by measuring the decay of radioactive isotopes within minerals. This process provides a chemical clock that allows scientists to determine the absolute age of rock samples. The discovery that the planet's age exceeded four billion years [1] fundamentally altered the trajectory of Earth sciences.

This scientific pivot discarded previous chronological frameworks in favor of a model based on physics. The ability to date the Earth provided the necessary temporal scale to support the theory of plate tectonics, and the long-term evolution of the atmosphere and oceans.

The documentary said this period of discovery paved the way for modern geology [1]. By establishing a reliable timeline, scientists could finally map the history of the planet from its chaotic beginnings to its current state.

“Earth is more than 4 billion years old”

The transition from biblical chronology to radiometric dating represents a fundamental shift in the human understanding of time. By moving the age of the Earth into the billions of years, science created the necessary window for complex biological evolution and slow-moving geological processes to occur, effectively separating natural history from theological narrative.