Quick Facts
About Pluto
Pluto was discovered on February 18, 1930 by astronomer Clyde Tombaugh at the Lowell Observatory in Flagstaff, Arizona. It was named after the Roman god of the underworld, suggested by 11-year-old Venetia Burney of Oxford, England.
Pluto's surface is covered with ices of nitrogen, methane, and carbon monoxide. It has a thin atmosphere that expands when it approaches the Sun and collapses as it moves away. The iconic heart-shaped nitrogen ice plain known as Tombaugh Regio was revealed by NASA's New Horizons spacecraft in 2015.
Despite its small size — roughly two-thirds the diameter of Earth's Moon — Pluto has a complex geological landscape including mountains, plains, valleys, and possibly subsurface oceans of liquid water beneath its icy crust.
Moons of Pluto
Pluto has five known moons. Its largest moon, Charon, is so big relative to Pluto that the two are often considered a binary system — they orbit a common center of gravity between them.
Exploration
NASA's New Horizons spacecraft made the first and only close flyby of Pluto on July 14, 2015, traveling at over 50,000 km/h. It captured unprecedented images and data, revealing a geologically active world far more complex than scientists had expected.
New Horizons data continues to be analyzed to this day, providing new insights into the geology, atmosphere, and composition of this distant world.