Urbain Jean Joseph Le Verrier was born in 1811 to a poor family in a rural region of northwest France, near the English Channel. Despite his humble origins, it soon became evident that he was an extremely bright boy, and at great expense his parents sent him to the University of Paris. There he excelled and emerged with a promising future in chemistry, but he soon lost interest in the field and turned to astronomy.

Le Verrier did not take long to become embroiled in one of the high-profile astronomical pursuits of the day--the search for new planets. Sir William Herschel had discovered the planet Uranus in 1781, but by the time Le Verrier entered professional astronomy, it was evident that the motion of Uranus was not following predictions, and that some unknown body must be perturbing it. The obvious supposition was another, undiscovered planet beyond Uranus, and astronomers on...