Facts about Pluto
- 09
Pluto's orbital period around the Sun spans 248 Earth years, meaning the dwarf planet has completed only one full orbit since its discovery in 1930.
- 08
Pluto rotates on its side with an axial tilt of 120 degrees, meaning it spins backwards relative to most other planets in our solar system.
- 07
Temperatures on Pluto's surface plunge to minus 380 degrees Fahrenheit, making it one of the coldest known planetary bodies in our solar system.
- 06
Pluto's five moons—Charon, Styx, Nix, Kerberos, and Hydra—were discovered between 1978 and 2012, with the four smaller ones identified only after the dwarf planet's reclassification in 2006.
- 05
Methane ice covering Pluto's surface absorbs ultraviolet radiation and transforms into tholins, complex organic molecules that give portions of the dwarf planet a reddish-brown coloration.
- 04
At 2,377 kilometers in diameter, Pluto is smaller than Earth's moon but contains five known moons orbiting within its gravitational system.
- 03
Charon, Pluto's largest moon discovered in 1978, is so massive relative to its primary that the two bodies orbit around a common center of gravity located in space between them.
- 02
Pluto's thin nitrogen atmosphere collapses and freezes onto its surface during its most distant orbital points, occurring roughly every 124 Earth years.
- 01
New Horizons spacecraft captured Pluto's first high-resolution images in July 2015, revealing a 1,600-kilometer-wide heart-shaped region on its surface.