Dwarf planets are miniature versions of our solar system’s planets. They are comparatively small objects similarly to planets. The term “dwarf planet” arose from a heated debate over whether Pluto should be classified as a planet. Pluto was thought to be the solar system’s ninth planet for 50 years. However, the International Astronomical Union (IAU) redefined “planet” in 2006, allowing only eight bodies in the solar system to be classified as such. Simultaneously, it established a new, distinct class of objects known as dwarf planets.
Pluto is the only dwarf planet that was thought to be a major planet at one time. It is now known to be one of the largest members of the Kuiper belt. It was once the ninth and most distant planet from the Sun, a shadowy disc-like zone beyond Neptune’s orbit teeming with comets. It is the second-largest dwarf planet, after Eris.
Scientists believe Pluto’s internal structure is differentiated, with the rough material sinking into a dense core surrounded by a mantle of water ice. Because the decay of radioactive components, it would eventually heat the ice enough to separate it from the rock. Such heating could still be occurring today, resulting in a subsurface sea layer of fluid water at the core-mantle boundary.
Pluto's icy surface
Pluto’s surface has a temperature of about -225°C, making it one of the coldest places in the solar system. For a long time, astronomers didn’t know much about its surface, but the Hubble Space Telescope revealed a reddish, yellowish, grey planet with an unusual bright spot near the equator that may be rich in carbon.
Pluto's birth and early years
The main hypothesis behind the development of Pluto and Charon is that a rising Pluto was hit by another Pluto sized object. While most of the combined matter became Pluto, the rest spun off to become Charon.
The satellites of Pluto
Pluto has a nearly half-size moon named Charon after the Greek mythological demon. Pluto and Charon are separated by 19,640 kilometers, which is less than the distance between London and Sydney. The orbit of Charon around Pluto lasts 6.4 Earth days and one Pluto rotation, also known as a Pluto day. This is because Charon is hovering over the same area of Pluto’s surface as Pluto. The dwarf planet appears to be reddish, whereas Charon appears to be greyish. It is covered in nitrogen and methane, while Charon is covered in ordinary water ice, according to scientists. The Pluto-Charon system is tipped on its side when compared to the majority of the planets and moons in the solar system. This is in reference to the Sun. Pluto also rotates from east to west. Its rotation is backward in comparison to the other planets and moons in its orbit.
Pluto’s orbit is highly eccentric, or far from elliptical, implying that its distance from the Sun varies greatly. It’s orbit occasionally intersects Neptune’s orbit. Pluto’s surface ice defrosts as it gets closer to the Sun, creating a thin environment for a short time. It’s primarily nitrogen, with a trace of methane thrown in for good measure. Pluto’s atmosphere extends beyond that of Earth due to its low gravity. As the dwarf planet moves away from the Sun and cools, the visible gases all around settle back onto the surface. Pluto’s atmosphere may become insignificant when it is the farthest away from the Sun.
Pluto's other moons
In total Pluto has altogether 5 moons. Hydra and Nix (discovered in 2005), Kerberos (discovered in 2011), and Styx are Pluto’s other moons (discovered in 2012).