What Is #31: The Kuiper Belt?

The day after Christmas is a great day for astronomy. Today I return to the What Is series and take a look at the Solar System's Kuiper Belt. The Kuiper Belt is a region in the Solar System that extends from about 30 astronomical units (A.U.) to about 50 A.U. from the Sun. For reference, the Earth is 1 A.U. from the Sun. There are many leftover parts from the early ages of the Solar System that never collected into a planet or with one of the existing planets. Given the larger distance from the Sun, many of these objects are more icy and less rocky in composition.

Short period comets, such as Halley's comet, which orbits the Sun once every 76 years, originate from the Kuiper Belt. Pluto, and several other dwarf planets, are in the region of the Kuiper Belt in the Solar System. 

The Kuiper Belt is named after astronomer Gerard Kuiper, although he did not discover the Kuiper Belt. He did a great deal of work in planetary astronomy, including the discovery of a couple of moons of Uranus. The Kuiper Belt was discovered two decades after Kuiper's death as technology improved and non-planet objects were discovered in increasing numbers in this distance range.

Is the Kuiper Belt the edge of the Solar System? Nope! Far from it. Coming soon we'll talk about the Oort Cloud which is very far out in the Solar System, far more distant than the Kuiper Belt.