Xavier Le Pichon came to Lamont Geological Observatory in 1959 and spent four months aboard the R/V Vema as a physical oceanography technician. The research cruise set out to test the existence of the mid-ocean ridge system: a long chain of seismically active mountains running along the ocean floor.

Le Pichon would go on to be one of the scientists on the forefront of the plate tectonics revolution – a theory that changed the way we understand our planet. Instead of being a solid mass, scientists discovered Earth is made up a series of plates that move and slide past each other, causing volcanic eruptions, earthquakes and geological formations. It was the discovery of the mid-ocean ridge system and magnetic anomalies on the ocean floor that led scientists to develop the theory of seafloor spreading, the process by which oceanic crust is renewed and a key piece in the development of plate tectonic theory.

In this new Centennial episode of Third Pod from the Sun, Le Pichon recounts the changes that took place in Earth science during the 1950s and 60s that led to the solidification of the theory, his own work developing the first global plate kinematic model and reconstructing how the planet looked like billions of years ago, and what it was like to be a young scientist challenging deeply held scientific theories.

This episode was produced by Nanci Bompey and mixed by Collin Warren.