The status of Pluto as a planet has been a subject of scientific debate and discussion for many years. In 2006, the International Astronomical Union (IAU) redefined the definition of a planet, which led to Pluto being reclassified as a "dwarf planet" rather than a full-fledged planet.
According to the IAU's definition, a planet must meet three criteria:
It must orbit the Sun: Pluto satisfies this criterion as it orbits the Sun, albeit in an elongated and inclined orbit.
It must be spherical in shape: Pluto is mostly spherical, which meets this criterion. However, being spherical is not unique to planets and can be observed in other celestial objects as well.
It must have cleared its orbit: This is where Pluto falls short. According to the IAU, a planet must have cleared its orbit of other debris, meaning it should be the dominant gravitational force in its orbit and have "cleared out" other objects from its path. Pluto shares its orbit with numerous other objects in the Kuiper Belt, a region beyond Neptune that contains many small icy bodies. Therefore, Pluto is considered a dwarf planet rather than a planet under the current definition.
The reclassification of Pluto was met with some controversy and continues to be a topic of discussion among scientists and the general public. Some argue that the definition of a planet should be revised to include Pluto, while others support the IAU's decision based on the established criteria.