1. Basic Facts
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Name: Pluto
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Type: Dwarf planet (sometimes called a small icy/rocky planet)
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Average distance from the Sun: About 5.9 billion km (39.5 astronomical units)
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Diameter: Approximately 2,377 km (about 18% of Earth’s diameter)
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Mass: About 0.2% of Earth’s mass
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Orbital period: About 248 Earth years
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Rotation period: About 6.4 Earth days
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Discovered: In 1930 by Clyde Tombaugh
2. Status and Location
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Originally classified as the ninth planet of the Solar System, Pluto was reclassified as a dwarf planet in 2006 by the International Astronomical Union (IAU).
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It resides in the Kuiper Belt — a region of icy bodies beyond Neptune’s orbit.
3. Orbit
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Pluto’s orbit is highly elliptical and tilted about 17° relative to the plane of the planets.
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Sometimes Pluto comes closer to the Sun than Neptune, but they never collide because their orbits are in a resonance that keeps them stable.
4. Composition and Surface
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Pluto is made mainly of rock and ice.
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Its surface is covered with frozen nitrogen, methane, and carbon monoxide.
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Average surface temperature is extremely cold, around −230 °C (−382 °F).
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Features include icy mountains, plains, and frozen deserts.
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It has a very thin atmosphere mostly of nitrogen, which freezes onto the surface in the winter.
5. Moons
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Pluto has 5 known moons:
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Charon — the largest, about half the diameter of Pluto, so big that Pluto and Charon are sometimes considered a double dwarf planet system.
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Other smaller moons: Styx, Nix, Kerberos, and Hydra.
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6. Exploration
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Discovered in 1930 by astronomer Clyde Tombaugh.
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In 2015, NASA’s New Horizons spacecraft flew by Pluto, providing the first close-up images and detailed data on its surface, atmosphere, and moons.
7. Interesting Facts
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Pluto and Charon are tidally locked, always showing the same face to each other.
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Pluto is the largest known object in the Kuiper Belt.
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Despite its small size, Pluto has complex geology and a thin atmosphere.