Why do people think there is a giant “hidden” planet somewhere in the depths of our solar system?

Question

Why do people think there is a giant “hidden” planet somewhere in the depths of our solar system?

In: 5

Answer 1

Basically there are some odd orbital properties to some objects in our solar system and one explanation for the cause is a large planet with an elongated orbit that’s fairly distant from the sun.

https://solarsystem.nasa.gov/planets/hypothetical-planet-x/in-depth/