He is best known for formulating the Titius–Bode law, and for using this rule to predict the existence of a celestial object at 2.8 AU from the sun. This happened in 1766, when he inserted his observation on planetary distances into a German translation of Charles Bonnet's book Contemplation de la Nature. His suggestion that the object would necessarily be small was later superseded by the claim of Johann Elert Bode for a planet-like object, subsequently identified as being Ceres.