The conversation between human and AI assistant.
Why isn't Pluto a planet?
Why was it reclassified?
Pluto was reclassified as a dwarf planet because the IAU changed their definition of what a planet is. According to their new definition, a planet must meet three criteria: it must orbit the sun, it must be spherical in shape, and it must have cleared its orbit of debris. Pluto failed to meet the third criteria because it shares its orbit with many other objects in the Kuiper Belt.