Pluto
Pluto is the smallest planet and the farthest planet from the sun. The planet orbit is 5,913,520,000 km., its diameter is 2274 km, and the mass is 1.27e22 kg. Pluto have a density of 1,750 kg/m^3. The minimum distance that Pluto is from the Sun is 3.43 billion km. The maximum distance from the Sun is 7.4 billions km. The average surface temperature is -229o C (-380o F) or 44K. It takes the planet 248 years to rotate around the Sun.
Pluto's moon is called Charon. Charon is very close to Pluto and is about the same size as Pluto. Charon is 12,200 miles away from Pluto and has a diameter of 1,200 km. They obit with each other like a double planet. Scientist assume that Pluto and Charon are made of the same thing. Pluto is even smaller than the moon Jupiter's moon, Ganymede.
Pluto has two different parts, the icy part and the non-icy part. Scientist think that the icy part is made of frozen nitrogen but also contain smaller amount of frozen carbon monoxide and methane. Scientists think that Pluto is good at reflecting light with the icy part and they suggest that they are made of icy component which mean that Pluto is mostly covered with nitrogen.
Pluto can be an atmosphere because it is so cold at 39AU (astronomical unit). When Pluto is closer
to the sun the ice on the planet evaporate and form into an atmosphere. Pluto's
air is mostly made of nitrogen gases and carbon monoxide. Pluto's atmosphere is larger and there
might even be clouds and winds on the planet but it is very hard to see it.
Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune Pluto