1781年3月,威廉·赫歇耳发现了天王星。天王星被发现后,人们又发现它的运行与根据牛顿理论推导的情形并不一致,这暗示在天王星轨道附近可能还有一颗行星影响着它的运行。1846年,35岁的法国数学家勒维耶计算出了那颗假想行星所在的位置和质量,他把计算结果告诉了他的朋友——柏林天文台的天文学家约翰·格弗里恩·伽勒。 March 1781, William Herschel discovered Uranus. Once Uranus was discovered, it was found that its behavior was inconsistent with that derived from Newton’s theory, suggesting that there might be a planet near Uranus orbit that affected its operation. In 1846, Levier, a 35-year-old French mathematician, calculated the location and the mass of the imaginary planet. He told his friend, the result of the calculation, that the astronomer John Göflin-Geller of the Berlin Observatory .