Gravity, the attracting force between all matter, also attracts planets. Due to the changes in the orbits of the known planets in the early 1900s, it was assumed that there was one or more planets beyond Neptune, but not yet identified. Pluto was the first of these to be identified, but in recent years, a significant number of small planetoids have been discovered.
Current speculation in the astronomical community due to the gravitational disturbances of the planets suggest that there may be a larger planet, or even a [brown dwarf]? circling the Sun at a very large distance.
cubewano?s are anhoter kind of Trans-Neptunian objects