A Modern Planet

Neptune is the eighth planet from the Sun and, in modern astrology, the ruler assigned to Pisces. Its discovery was a triumph of prediction, its position calculated from irregularities in the orbit of Uranus before it was seen. The naming was less tidy than the mathematics. Urbain Le Verrier, whose calculations had led astronomers to the new planet, at first proposed naming it for himself, then settled on the Roman god Neptune and paired the name with a trident glyph fitting to a sea god, but rival names and symbols circulated internationally for months amid a dispute over priority between French and English astronomers that was never fully resolved to either side's satisfaction.

The matter was only settled formally in August 1847, when the Bureau des Longitudes in Paris announced it would follow the astronomical convention already spreading elsewhere and adopt Neptune as the planet's official name, by which point Le Verrier's trident sign had already become the design most in use and simply carried on as the standard glyph. The episode is often cited by historians of astronomy as a cautionary case of how quickly scientific priority disputes can outrun the tidy naming conventions they are meant to serve, with a symbol settling into general use well before the argument over the planet's name had actually been resolved.