Pluto | The Dwarf Planet Formerly Known As A Planet
God Of The Underworld!
Here you can learn lots of interesting facts about the planet which for 76 years was considered the solar system’s 9th planet! Now classed as a dwarf planet, Pluto is a complex and mysterious world in the deep cold Kuiper belt. The largest dwarf planet, it is orbited by 5 moons. The biggest is Charon which is so big some consider the Pluto-Charon system the first ‘double dwarf planet’!
Fast Summary Facts About Pluto
- Discovered: February 18th, 1930 by Clyde Tombaugh
- Name Origin: Named after the Roman god of the underworld
- Size: Diameter 2,377 km (1,477 miles)
- Number of Moons: 5
- Dwarf Planet Rank: Largest
- Surface Gravity: Only 0.063 g (just 6% of Earth’s gravity!)
- Orbit Perihelion: 29.7 AU
- Orbit Aphelion: 49.3 AU
- Orbital Period: 248 years (90,530 days)
- Orbital Inclination: 17.16° to the ecliptic
- Rotational period: 153 hours (6 days, 9 ¼ hours)
- Surface: Water-ice & nitrogen-ice
- Surface Temperature: Average of -229 °C (44K)
Interesting Fun Space Facts About Pluto!
- Pluto is believed to have formed during the accretion phase in the early solar system about 4.5 billion years ago. It didn’t merge with an existing planet or go on to grow big enough to become a planet.
- During the early 20th century, the search for a ‘planet X’ beyond Neptune was carried due to observed changes in Uranus’ orbit. After a year searching photos of the night sky, the young astronomer Clyde Tombaugh found a ‘moving star’ which he’d been searching for.
- Disney’s lovable dog ‘Pluto’ was named after the newly discovered ‘planet’ in 1930.
- For the first 76 years after its discovery, Pluto was considered a planet. However, other dwarf planets like Makemake and Eris, were discovered from 2003 so in 2006 astronomers determined that Pluto was a dwarf planet like several other large objects discovered in the Kuiper belt region of the outer solar system.
- Pluto is (currently) the largest dwarf planet discovered. However, it is only the second most massive, with Eris being heavier!
- Pluto has an elliptical and tilted orbit compared to the planets. This means for 20 years of its 248-year orbit it is closer to the Sun than Neptune!
- On average Pluto is over 5.9 billion kilometres (3.7 billion miles) from the Sun, this is 39 times the distance Earth is from the Sun!
- With an axial tilt of 57°, Pluto basically orbits the Sun on its side, rotating backwards. This is similar to Uranus.
- Pluto is so far away, that the midday sunlight is 900 times dimmer than on Earth and it takes sunlight 5 ½ hours to reach it!
- Pluto has five known moons – Charon, Hydra, Nix, Kerberos and Styx. All names related to the god of the underworld.
- The largest moon Charon is half the size of Pluto, making it the largest moon relative to the body it orbits in the solar system! This is why some astronomers refer to Pluto & Charon as a ‘double dwarf planet’.
- Pluto’s surface is a complex mix of craters, valleys, water-ice mountains coated with methane snow and smooth plains made of nitrogen ice resembling a frozen lake!
- Pluto has a thin atmosphere made of nitrogen, methane and carbon monoxide when near perihelion. It freezes and falls as snow when Pluto is far from the Sun.
- The New Horizons probe, which launched in 2006, is the only spacecraft to have visited Pluto. After 9 1/2 years travelling across the solar system, the probe flew by the dwarf planet on July 15th 2015 capturing stunning images while also studying this distant Kuiper belt object.