The Oort cloud: Cometary collisions

The Oort cloud, a reservoir of comets beyond the orbits of Pluto and Neptune, was formed by the ejection of icy planetisimals from the giant planets region of the solar nebula. A study of the collision processes that must be involved in this clearing process suggests that, in the conditions prevailing in the standard nebular disk models, most of the planetisimals would have been ground up by erosion before they had time to be ejected into the Oort cloud. But there is an Oort cloud, so either some other form of escape mechanism must have been in operation, or the cloud may be less massive than presently believed.

Rapid collisional evolution of comets during the formation of the Oort cloud
S. ALAN STERN, PAUL R. WEISSMAN
Nature 409, 589-591 (1 February 2001)
| First Paragraph | Full Text | PDF |

1 February 2001 table of contents