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A dwarf planet is a type of celestial body that has certain characteristics which distinguish it from a full-fledged planet. The term 'dwarf planet' was introduced by the International Astronomical Union (IAU) in 2006.

To be categorized as a dwarf planet, a celestial body must satisfy specific criteria:

• It must orbit the sun.
• It should have sufficient mass for its gravity to make it nearly round.
• Unlike a planet, it has not cleared its neighboring region of other objects.

This reclassification was necessary because Pluto and other similar celestial bodies did not meet the full criteria set for planets, primarily because they share their orbital zones with other objects. Understanding dwarf planets helps astronomers to classify and differentiate diverse objects in our solar system.

The International Astronomical Union (IAU) is the authority responsible for naming and classifying celestial bodies. Founded in 1919, the IAU aims to promote and safeguard the science of astronomy in all its aspects.

Responsibly setting the guidelines for astronomical practices, the IAU defines the characteristics that distinguish planets from other celestial bodies. The IAU's 2006 definition of planets led to the creation of the category 'dwarf planet', which resulted in the reclassification of Pluto.

Through their work, the IAU ensures that astronomical nomenclature and classifications remain consistent and internationally recognized, helping scientists collaborate and communicate more effectively.

Pluto was discovered in 1930 and was considered the ninth planet in our solar system for many decades. This icy world, located in the Kuiper Belt, is relatively small compared to the other planets.

In 2006, the International Astronomical Union redefined what it means to be a planet, which resulted in Pluto's reclassification as a dwarf planet.

This change generated much debate and emotional reactions, as Pluto had become ingrained in culture and education over the years. Despite its reclassification, Pluto remains a subject of interest. NASA's New Horizons mission in 2015 revealed stunning images and data that continue to shed light on this intriguing world.

Celestial bodies are natural objects located outside Earth's atmosphere. They include planets, moons, asteroids, comets, stars, and galaxies. Each type of celestial body has its own characteristics, composition, and dynamics.

Understanding celestial bodies is crucial to comprehending the universe's structure and evolution.

• Planets: Major celestial bodies that orbit a star.
• Moons: Objects that orbit planets.
• Asteroids and Comets: Smaller objects, primarily composed of rock, metal, and ice.

Scientific exploration, often guided by definitions and classifications set by entities like the IAU, allows astronomers to categorize these objects efficiently, enhancing our knowledge about space.