Pluto was discovered in 1930 by an astronomer from the United States. An astronomer is a person who studies stars and other objects in space.
Pluto was known as the smallest planet in the solar system and the ninth planet from the sun.
Today, Pluto is called a “dwarf planet.” A dwarf planet orbits the sun just like other planets, but it is smaller. A dwarf planet is so small it cannot clear other objects out of its path.
Pluto (minor-planet designation: 134340 Pluto) is a dwarf planet in the Kuiper belt, a ring of bodies beyond Neptune. It was the first Kuiper belt object to be discovered. It is the largest and second-most-massive known dwarf planet in the Solar System and the ninth-largest and tenth-most-massive known object directly orbiting the Sun. It is the largest known trans-Neptunian object by volume but is less massive than Eris, a dwarf planet in the scattered disc. Like other Kuiper belt objects, Pluto is primarily made of ice and rock[13] and is relatively small—about one-sixth the mass of Earth's Moon and one-third its volume. It has a moderately eccentric and inclined orbit during which it ranges from 30 to 49 astronomical units or AU (4.4–7.4 billion km) from the Sun. This means that Pluto periodically comes closer to the Sun than Neptune, but a stable orbital resonance with Neptune prevents them from colliding. Light from the Sun takes about 5.5 hours to reach Pluto at its average distance (39.5 AU).
Pluto was discovered by Clyde Tombaugh in 1930, and was originally considered the ninth planet from the Sun. After 1992, its status as a planet fell into question following the discovery of several objects of similar size in the Kuiper belt. In 2005, Eris, which is 27% more massive than Pluto, was discovered, which led the International Astronomical Union (IAU) to define the term "planet" formally for the first time the following year.[14] This definition excluded Pluto and reclassified it as a member of the new "dwarf planet" category.[15]
Pluto has five known moons: Charon (the largest, with a diameter just over half that of Pluto), Styx, Nix, Kerberos, and Hydra.[16] Pluto and Charon are sometimes considered a binary system because the barycenter of their orbits does not lie within either body.[17] The IAU has not formalized a definition for binary dwarf planets, and Charon is officially classified as a moon of Pluto
What Is Pluto Like?
Pluto is very, very cold. The temperature on Pluto is 375 to 400 degrees below zero. Pluto is so far away from Earth that scientists know very little about what it is like. Pluto is probably covered with ice.
Pluto has about one-fifteenth the gravity of Earth. A person who weighs 100 pounds on Earth would weigh only 7 pounds on Pluto.
Most planets orbit the sun in a near-circle. The sun is in the center of the circle. But Pluto does not orbit in a circle! The orbit of Pluto is shaped like an oval. And the sun is not in the center. Pluto's orbit is also tilted.