The celebrated Carl Friedrich Gauss, at just twenty-four years old, provided astronomers with the means to recover the asteroid Ceres, developing a new method for determining the orbit of a generic celestial body based on just three observations. The method was based on the use of least squares, a methodology Gauss developed specifically for astronomy, but which, given its effectiveness, would later spread to many other fields. Within weeks, Gauss predicted Ceres’s trajectory based on data previously collected by Piazzi and communicated his results to Franz Xaver, editor of the Monatliche Correspondenz. On December 31, 1801, Zach and Heinrich Olbers confirmed Ceres’s rediscovery with certainty. Johann Elert Bode thinks Ceres is the “missing planet” predicted by Johann Daniel Titius, orbiting between Mars and Jupiter at a distance, according to the Titius-Bode law, of 419 million kilometers (2.8 AU) from the Sun. Ceres is given a planetary symbol, and remains listed as a planet in astronomical tables and books for about half a century, until further asteroids are discovered. Ceres turns out to be disappointingly small, and its disk indistinguishable; thus, William Herschel coined the term “asteroid” (“starlike”) to describe it. It will be reclassified as a dwarf planet in 2008.
