It seems that we already have an abundance of knowledge about the universe, but the reality is that there is still an astronomical amount of information that has yet to be discovered in our own solar system. There has been a discrepancy over the planetary status of Pluto, but despite that, there are even more questions to be answered regarding exactly how many planets are in our solar system.
Evidence that supports the possibility of a Giant Planet X orbiting on the outer edge of our solar system continues to mount. This potential planet would be extremely difficult to spot because of its huge distance from the others. Even though the planet has yet to be discovered, NASA strongly believes in the existence of Planet X because its presence would explain several theories and measurements of other known objects in the Kuiper Belt.
According to Caltech planetary astrophysicist Konstantin Batygin, “There are now five different lines of observational evidence pointing to the existence of Planet X.” There are five smaller objects in the Kuiper Belt with unique orbits that would be explained by the existence of the much larger planet.
If Planet X does exist, the only thing left to do is locate and identify it. Unfortunately, that's much easier said than done as it is expected to be a frigid world positioned so away that it would take an estimated 10,000 - 20,000 Earth years just to make one orbit around the sun.