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When Was Pluto Reclassified as a Dwarf Planet?

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Quick Answer

The International Astronomical Union reclassified Pluto as a dwarf planet on 24 August 2006.

The Full Story

On 24 August 2006 the International Astronomical Union (IAU) adopted a formal definition of "planet" that required a body to have cleared its orbital neighbourhood. Pluto, discovered by Clyde Tombaugh in 1930, shares its orbital zone with numerous Kuiper Belt objects and was therefore reclassified as a dwarf planet. The decision was contentious — some planetary scientists still disagree. NASA's New Horizons spacecraft flew past Pluto in 2015, revealing a surprisingly complex world with mountains and nitrogen glaciers.

Key Facts

1.Pluto is about 2,377 km in diameter — smaller than Earth's Moon.
2.The IAU's vote took place in Prague with roughly 400 of its 10,000 members present.
3.Pluto has five known moons; the largest, Charon, is about half Pluto's size.

YouTube Angle

Suggested video title for this topic:

"Why Pluto Lost Its Planet Status — The 2006 Decision Explained"

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