>>12792303It's likely very small (bigger than Earth, smaller than the Ice Giants) which makes it relatively small, it's getting very, very little light (for comparison, the "day" at Pluto would be darker than the darkest night on Earth), and it's very, very far away and in a crazy unusual orbit.
That being said it's highly speculatively and I personally think there is only a very small possibility of it being a real thing. Personally I suspect those TNO orbits were fucked up by a passing star or rogue planet or something millions-billions of years ago and have just been fucked up ever since. Even with conditions being as bad as they are for spotting a planet 9 now that we have a theoretical model of it's size and orbit it should be possible to see it and yet, nothing. Everyone wants to be the guy who finds a new planet, even if it seems really unlikely.
