It's Pluto's orbit that keeps it from being a planet, not its' size.Here are the orbits of Neptune and Pluto for 200 years:

as well as Saturn and Uranus. Saturn has about 6.8 laps, Uranus about 2.4, and 1.25 for Neptune. From the proximity to Neptune's orbit at one point, the only time where the orbital planes are the same, you have to figure that at some future date, Neptune will capture Pluto/ Chiron as moons, or there will be a collision with Neptune, or one of its moons.

as well as Saturn and Uranus. Saturn has about 6.8 laps, Uranus about 2.4, and 1.25 for Neptune. From the proximity to Neptune's orbit at one point, the only time where the orbital planes are the same, you have to figure that at some future date, Neptune will capture Pluto/ Chiron as moons, or there will be a collision with Neptune, or one of its moons.


