The existence of the planet Neptune was deduced in the 1840's from disturbances it caused in the orbit of which other planet ?
Definition of planet planets", or "small planets", though it took the first four asteroids longer to be grouped as such. To this day, "minor planet" remains the official designation for all small bodies in orbit around the Sun, and each new discovery is numbered accordingly in the IAU's Minor Planet Catalogue. The long road from planethood to reconsideration undergone by Ceres is mirrored in the story of Pluto, which was named a planet soon after its discovery by Clyde Tombaugh in 1930. Uranus and Neptune had been declared planets based on their circular orbits, large masses and proximity to the ecliptic plane. None
Planet Nine Nine. Following the discovery of the planet Neptune in 1846, there was considerable speculation that another planet might exist beyond its orbit. The Planet Nine hypothesis predicts a specific planet of a certain size and with certain orbital characteristics that are different from past theories. Attempts to detect planets beyond Neptune by indirect means such as orbital perturbation date back beyond the discovery of Pluto. George Forbes was the first to postulate the existence of trans-Neptunian planets in 1880, and his work is considered similar to more recent Planet Nine theories. In Forbes's model the planet had a semi-major axis