na <kelfe12-nospam-@yahoo.com> wrote in message news:<pan.2004.05.20.00.36.13.672523@yahoo.com>...

Was thinking it would be smarter to track large commets and other fast
moving objects, in seach of unusual deviations on course, i.e. planets
protected from impact.

I don't think any aliens could live on a comet, asteroid, etc. Theyre
too small and dont have an atmosphere. First of all one would have to
detect such errant  bodies. Seti only looks at a few tiny dots/lines
in the sky and what is needed for asteroid/meteor detection is
something that can see the whole sky. The detector would have to be
very sensitive - It is hard to see a 100-meter object at
interplanetary distances. Once the body is detected and several photos
taken it only requires one computer and good astrometry to find its
predicted path.