https://pubs.aip.org/physicstoday/article/72/3/70/916004/The-Planet-Nine-hypothesisThe-putative-planet There are too many minor planets orbiting in the same direction to be a fluke, and I think the Planet Nine hypothesis makes the most sense

https://manifold.markets/RyanGuill/will-planet-9-be-discovered-before?r=Unlhbkd1aWxs

Will planet 9 be discovered before 2030?

23% chance. Planet 9 is a hypothetical gravitational object in the outer solar system, that would explain the orbits of some trans neptunian objects. https://en.wikipedia.org/wiki/Planet_Nine If any object with mass is discovered that explains these orbits before midnight US/Eastern time on 1/1/2030, this question will resolve YES.

Does the planet need to fit within the parameters defined in the Batygin and Brown hypothesis? E.g 0.2 <= eccentricity <= 0.5 ?

@JonLamb No, it just needs to be any planet that could reasonable be considered Planet Nine. i.e. if scientists announce "we found Planet Nine!", that counts.

But did it clear its path? Is it really a planet than?

https://astrobiology.nasa.gov/news/the-case-strengthens-for-planet-9/