Pluto

Pluto is a dwarf planet in the Kuiper belt, beyond Neptune. Its large moon Charon and varied icy surface make it a distinctive member of the outer Solar System.

Charon: Charon is Pluto’s largest moon, so massive relative to Pluto that the pair orbit a shared point outside Pluto. Its size makes Pluto and Charon behave more like a binary system than a typical planet–moon pair.
New Horizons: New Horizons is NASA’s spacecraft that made the first close flyby of Pluto in 2015. Its observations supplied the detailed images and measurements behind modern knowledge of Pluto.
Clyde Tombaugh: Clyde Tombaugh was the American astronomer who discovered Pluto at Lowell Observatory in 1930. His photographic search identified Pluto after years of predictions and unsuccessful searches.
Eris: Eris is a dwarf planet in the scattered disc, discovered in 2005 and similar in size to Pluto. Its discovery intensified debate over whether Pluto and comparable bodies should count as planets.
Pluto–Charon barycenter: The Pluto–Charon barycenter is the shared center of mass around which Pluto and Charon orbit. The barycenter lies outside Pluto, a defining consequence of Charon’s unusually large size.
Tombaugh Regio: Tombaugh Regio is a large, bright, heart-shaped region on Pluto’s surface. Its prominent two-lobed outline became the mission’s most recognizable view of Pluto.
Percival Lowell: Percival Lowell was an American astronomer who founded the observatory where Pluto was discovered. His search for a predicted ninth planet set the project in motion, though his proposed position was inaccurate.
Ceres: Ceres is a dwarf planet in the asteroid belt and the largest object between Mars and Jupiter. Unlike Pluto, Ceres occupies the inner Solar System and lies among rocky asteroids.
Pluto's atmosphere: Pluto’s atmosphere is a thin, variable envelope composed mainly of nitrogen, with methane and carbon monoxide. Seasonal sublimation of surface ices replenishes this atmosphere and changes its pressure.
Sputnik Planitia: Sputnik Planitia is a vast basin on Pluto filled largely with nitrogen ice. Its cellular ice plains indicate active convection and continual surface renewal.

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