Pluto is the farthest from the sun. It is also the ninth planet from the sun. And is the smallest planet-less then half the size of Mercury. Another reason Pluto is unusual is that its moon, Charon is more than half its size! In fact, Charon is the largest satellite relative to its planet in the solar system. On average, Pluto's orbit is 5.9 billion kilometers (3 2/3 billion miles) away from the sun.
All the planets orbit the sun in a path shaped like flattened circle. Of the entire planet, Pluto has the flattest orbit. Pluto's orbit is sometimes inside the orbit of its neighbor, Neptune. So for part of its journey about one - tenth - of it Pluto is closer to the sun than is Neptune. It takes almost 250 years for Pluto to orbit the sun.
Charon, Pluto's moon was discovered in 1978. Charon's surface is much darker.
It is probably covered with dirty water ice. Pluto and Charon always keep the same areas turned towards each other just like the Earth and the moon. Charon dose not really orbit around Pluto. Pluto and Charon together orbit each around a shared central point their barycenter. Barycenter is a common center of mass around which two or more bodies revolve.
Pluto is not made of solid rock, the way Earth is. Instead it may be a ball of frozen gases. It is very cold there. Temperatures may reach negative two hundred twenty degrees Celsius (negative three hundred sixty degrees Fahrenheit) at the planet.
From calculations of Pluto's density, it must be made of rock and ice. A very thin atmosphere of methane has been detected. While Pluto is covered by nitrogen ice, Charon is covered by water ice. Pluto is the only planet that has...