The Evolution of Pluto: From Planet to Dwarf Planet

Discovered in 1930 by Clyde Tombaugh, Pluto was initially hailed as the ninth planet. Its discovery was a triumph for predictive astronomy, filling an expected gap in the Solar System's architecture.

Pluto is smaller than Earth's moon and has a composition similar to many objects in the Kuiper Belt. This region beyond Neptune is filled with icy bodies, hinting at Pluto's true nature.

Pluto's orbit is highly eccentric and tilted, intersecting with Neptune's. This unusual path challenges the traditional view of planetary orbits and raised questions about its classification.

In the late 20th century, astronomers discovered several objects similar to Pluto in size and orbit. This prompted a debate about what constitutes a planet.

In 2006, the International Astronomical Union (IAU) established three criteria for planethood. Pluto failed to clear its orbit of debris, leading to its reclassification as a 'dwarf planet.'

Pluto's largest moon, Charon, is half its size, leading some to consider the pair a double planetary system. This unique relationship further distinguishes Pluto from the classical planets.

NASA's New Horizons mission in 2015 revealed Pluto's complex surface, including mountains of water ice and vast plains. These findings have reignited the debate about its planetary status.

Pluto has a thin atmosphere that expands and contracts dramatically as it orbits the Sun, causing seasonal changes unlike any other known planet or dwarf planet.