Which planet has been reclassified as a dwarf planet?

The reclassification of Pluto as a dwarf planet is significant due to its size and characteristics, which led to a debate within the astronomical community. Initially classified as the ninth planet of our solar system, Pluto was redefined in 2006 by the International Astronomical Union. The key criteria for a celestial body to be considered a planet include orbiting the Sun, being spherical in shape due to its own gravity, and having cleared its orbital neighborhood of other debris. Pluto fails to meet the last criterion because it shares its orbital zone with other objects in the Kuiper Belt, leading to its reclassification.

This change sparked discussions about what defines a planet and highlighted the diverse characteristics of celestial bodies within our solar system. Pluto's reclassification as a dwarf planet emphasizes the distinct types of objects that exist beyond the traditional definition of a planet, paving the way for a better understanding of planetary science and enhancing our knowledge about the formation and behavior of celestial bodies.