Pluto is still considered part of the solar system; however, its status as a planet has been a subject of debate and controversy among scientists and astronomers. In 2006, the International Astronomical Union (IAU) redefined the definition of a planet, which resulted in the reclassification of Pluto. According to the IAU's definition, a planet must meet three criteria:
- It must orbit the Sun.
- It must be spherical or nearly spherical in shape.
- It must have cleared its orbit of other debris.
Pluto meets the first two criteria but fails to meet the third one, as it shares its orbit with other objects in the Kuiper Belt, a region of the solar system beyond Neptune. Therefore, under the IAU's definition, Pluto was reclassified as a "dwarf planet."
Since then, Pluto has been officially referred to as a dwarf planet, distinguishing it from the eight planets that meet the IAU's criteria. However, it is important to note that the classification of celestial bodies can be a topic of ongoing scientific discussion, and some scientists and members of the public still consider Pluto a planet in its own right.