SKY & TELESCOPE'S NEWS BULLETIN -- APRIL 21, 1995
A team of astronomers led by Anita Cochran report that the Hubble Telescope may have detected extremely faint objects beyond Neptune in what is called the Kuiper Belt. The objects are roughly magnitude 28, which would make them only 20 km or so across. The astronomers painstakingly combined 34 HST images, then looked for things moving the way you'd expect for objects in distant, low-inclination orbits. This process turned up 59 candidate objects in a field only 4 arcminutes on a side. If these really are members of the Kuiper Belt, there must be about 60,000 such objects per square degree of sky. That would translate to a total of some 100 million comets traveling in low-inclination orbits and shining brighter than the HST's magnitude-28 limit.