The Evolution of Pluto: From Planet to Dwarf Planet

Pluto's Discovery
Pluto's Discovery
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.
Size and Composition
Size and Composition
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.
Orbital Peculiarities
Orbital Peculiarities
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.
Reclassification Debate
Reclassification Debate
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.
IAU's New Criteria
IAU's New Criteria
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 Moon Charon
Pluto's Moon Charon
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.
New Horizons Revelations
New Horizons Revelations
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.
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Who discovered Pluto?
Galileo Galilei
Clyde Tombaugh
Carl Sagan