Some time ago I read that for a star system to be able to sustain life it needs, besides a class M world, a gass giant, because it's gravity effects creates an asteroid belt, and prevents to many asteroids from hitting the M class world. Jupiter holds off asteroids, making Earth safe. Some kind of note of this should be added to the article (and perhaps also to Jupiter and Gas giant), but I can't find a good way to phrase it. -- Redge | Talk 17:53, 27 Aug 2004 (CEST)
Asteroid measurements Edit
During the merging of the information from "asteroid field" with "asteroid belt," I removed the following:
- Asteroids are measured by two methods, Schiller rating, and by size using a lettering system. For instance an asteroid field near the Rigel system has a Schiller rating of 3-5. The size is rated by letter, like a field in the Gamma Canaris region that has about 7000 bodies rating a size of A to N. 34% of them have atmospheres H to M, which capable of support life.