The International Astronomical Union (IAU) reclassified Pluto as a dwarf planet in 2006, sparking years of scientific debate and attempts to clarify the decision.The IAU's decision to demote Pluto from a planet to a dwarf planet in 2006 has prompted astronomers to revisit and refine the criteria for distinguishing planets from other celestial bodies. Central to this controversy is the question: why is Pluto no longer considered a planet?The issue stems from the definition—or lack thereof—of what constitutes a planet. Before 2006, there were no strict criteria for classifying planets. Instead, planets were loosely defined as objects larger than asteroids that orbited the Sun. For example, in the mid-1800s, more than a dozen objects considered planets at the time were later reclassified as asteroids.