On the number of planets in the outer solar system - Evidence of a substantial population of 1000-km bodies

If as presently suggested, in addition to comets, a possible large number of nearly 1000-km diameter planetary bodies may have been scattered into the Kuiper disk and Oort cloud, then the present population of planets in the outer solar system is greater than previously recognized. Calculations are presented which support this hypothesis by indicating that the large Uranus and Neptune tilts, the capture of Triton, and the formation of the Pluto-Charon binary, imply the past presence of numerous bodies of the scale presently cited in the 20-50 AU region. An evaluation is made of the prospects for detection of such bodies. 46 refs