The Kuiper Belt resides past the orbit of Neptune and is filled with millions of small icy bodies that are thought to have been left over from the formation of the outer planets. It is estimated that there are at least 35,000 objects in the Kuiper Belt that are at least 60 miles across. The 2 other Dwarf Planets that reside in the belt are Haumea and Makemake. Haumea is the 3rd dwarf planet from the sun and has an ellipsoid shape that is said to come from its rapid rotation. One day for the planet is 3.9 earth hours. It is presumed to be made of rock with a thick coating of Ice. Haumea has a surface temp of -241 degrees Celsius. Haumea takes 283 earth years to orbit the sun and has two small moons. Makemake is the second furthest dwarf planet from the sun and is the largest object in the Kuiper Belt. Makemake has a surface temperature of -239 degrees Celsius and the surface is covered with methane and ethane with a possibility of having nitrogen ices as well. If it did have an atmosphere it would most likely be made up of methane and nitrogen.
Comets and asteroids are both smaller celestial objects that orbit the sun but they are different in there makeup. Comets are usually made up of ammonia methane and water and only contain small amounts of rocky material where as an asteroid is composed more or rock and metal. Ceres which is also a Dwarf Planet is known as the first and biggest asteroid. Asteroids are known as the building blocks for planets. Asteroids can be from destroyed comets once all the ice is gone all that is left is the rocky