Oort Cloud
Links
Views of the Solar System: Oort Cloud
http://www.solarviews.com/eng/oort.htm
Definition and overview.
What's in the Oort Cloud? Both Less and More, New Study Suggests
http://www.planetary.org/html/news/articlearchive/headlines/2001/Oort1.htm/
Article discusses the nature of the spherical cloud of comets that surrounds our solar system.