To be considered a planet by the IAU, a celestial body must meet three criteria:
* It must orbit the Sun.
* It must have enough mass to be round.
* It must have cleared the neighborhood around its orbit.
Pluto meets the first two criteria, but it does not meet the third. Pluto's orbit is intersected by the orbits of several other objects, including the dwarf planet Eris. This means that Pluto has not cleared the neighborhood around its orbit and is therefore not a planet according to the IAU definition.
Some scientists believe that Pluto should still be considered a planet because it is so similar to other planets in our solar system. For example, Pluto has a solid surface, an atmosphere, and a magnetic field. However, other scientists believe that the IAU definition is correct and that Pluto should be considered a dwarf planet.
Ultimately, the decision of whether or not to consider Pluto a planet is a matter of semantics. There is no clear scientific definition of what constitutes a planet, and the IAU definition is simply one way of classifying celestial bodies.
