Pluto, once classified as the ninth planet in our solar system, has been a subject of controversy and intrigue since its discovery. Here are some key points about Pluto:
- Discovery: Pluto was discovered on February 18, 1930, by the American astronomer Clyde Tombaugh at the Lowell Observatory in Flagstaff, Arizona. Its discovery was the result of a systematic search for a ninth planet predicted to exist beyond Neptune.
- Classification: For much of the 20th century, Pluto was considered the ninth planet in our solar system. However, in 2006, the International Astronomical Union (IAU) reclassified Pluto as a "dwarf planet" due to new definitions of what constitutes a planet. According to the IAU definition, a celestial body must meet three criteria to be classified as a planet, and Pluto did not meet all three.
- Characteristics: Pluto is a small, icy world located in the Kuiper Belt, a region of the solar system beyond the orbit of Neptune that is populated by numerous small icy bodies. It has a highly elliptical and inclined orbit that takes it closer to the Sun than Neptune for about 20 years of its roughly 248-year orbit.
- Moons: Pluto has five known moons, the largest of which is Charon. Charon is relatively large compared to Pluto, leading some scientists to refer to the Pluto-Charon system as a "double planet."
- New Horizons Mission: In July 2015, NASA's New Horizons spacecraft made a historic flyby of Pluto, providing the first close-up images and detailed data about the dwarf planet and its moons. The New Horizons mission revealed Pluto to be a diverse and geologically active world with a complex surface featuring mountains, plains, and icy plains.
- Atmosphere: Pluto has a thin atmosphere primarily composed of nitrogen, with traces of methane and carbon monoxide. The atmosphere undergoes seasonal changes as Pluto orbits the Sun, with gases freezing out onto the surface as the dwarf planet moves farther from the Sun.