Kuiper belt objects are icy bodies in the outer solar system. They reside in a region past the orbit of Neptune. Pluto and Charon may be the largest examples of these objects. Several of these objects have been discovered during the last few years.
Object 1993 SC (GIF)
This image shows a small part of the discovery frames of 1993 SC,
one of the brightest Kuiper-Belt objects so far discovered. It was
taken using the 2.5m Isaac Newton Telescope on La Palma by Alan
Fitzsimmons, Iwan Williams and Donal O'Ceallaigh on 17th September 1994.
The two images are separated in time by 4.6 hours, and by comparing
them it is clear that one of the objects has moved from upper left of
center to almost merging with the image of a distant galaxy. This motion
marks it as being a distant member of our solar system, further away than
the planet Neptune.
Subsequent observations over the past year confirm that it is currently 34.0 AU from the sun but with a moderate orbital eccentricity of 0.18 it may travel as far as 48 AU. Assuming that it reflects light much like other primitive asteroids and comets in the out solar system, the diameter is around 300 km, or just a quarter the size of Pluto's moon Charon.
Comet
Other Comets