This extensively revised article was published in the November 2022 issue of the Institut de mécanique céleste et de calcul des éphémérides (IMCCE) Lettre d’information.
The institute is based at the Observatoire de Paris. A joint CNRS research unit, it is also affiliated with Sorbonne Université and the Université de Lille. It operates under the aegis of the Bureau des longitudes, preparing and publishing France's national ephemerides.
Lithograph of Laplace by François-Séraphin Delpech
after a drawing by Henri Regnault.
