As we look beyond Earth we realize that the closest part of the Universe is our Solar System. Even if that is the case, we still have a lot more to find out in our backyard. Thousands of years had to pass to understand how the planets went around the sun, and after hundreds of years later we came across Neptune and Uranus. Nowadays, we have four rocky inner planets, an asteroid belt, and four gaseous giants with rings and moons.
Beyond Neptune, however, there are a lot of unknown things. We might feel that there is just Pluto, some comets and the Kuiper belt, but the last decades revealed new object classes, some of them having yet-to-be-explained orbits.
There are some scientists saying that these objects prove the existence of Planet Nine. This would be a large planet found far beyond what we could see. Despite the things they say, these scientists face other peers who aren’t convinced yet. It is possible that Planet Nine doesn’t exist.
The story so far
Scientists from the ‘90s found the first object beyond Neptune that wasn’t part of the Plutonian system. Telescopes continued to be improved in both their field-of-view and magnitude and more and more objects were discovered.
The majority had orbits similar to Pluto’s: when they neared the sun, they orbited pretty close to Neptune. They were classified as part of the Kuiper belt. We also came across objects that weren’t part of the belt, such as Sedna, discovered in 2003. It is a dwarf planet, has a peculiar orbit and it takes it 10,000 years to revolve around the sun.
Scientists proposed that a large planet could influence Sedna’s – and other such objects – orbit pattern. However, things are yet to be clarified as scientists continue their research.