The Problem of the Earth’s Figure: Measurement, Theory, and Evidence in Physical Geodesy

My dissertation poject provides a new answer to a basic question: how did we come to have strong evidence for Isaac Newton's law of particle-to-particle gravitation? I argue that the answer lies buried in the history of physical geodesy, an often-overlooked research program aimed at deriving and measuring the Earth's figure. This is a bold claim because physicists, philosophers, and historians almost unequivocally assume that Newton's theory was tested in astronomy. I substantiate my claim by reconstructing the history of the problem of the Earth’s figure from Newton's Principia up to 1924. Getting this history right is not only about setting the record straight. Gravitational physics long served as a methodological paradigm for obtaining strong empirical evidence. Throughout my research, I show that the development of physical geodesy provides us with new lessons on how theorizing, measurement, and statistical inference contribute to empirical success.

Different geodetic measurement operations sketched in: Pierre Bouguer and Charles-Marie de La Condamine in La figure de la terre, Paris 1749.

Hydrostatic derivation of planetary equilibrium figure in: Alexis Clairaut, Théorie de la figure de la terre : tirée des principes de l'hydrostatique, Paris 1743.

Published research from this project:

*Winner of the 2022 APS History and Philosophy of Physics Essay Price

*Winner of the 2021 Du Châtelet Price in Philosophy of Physics