SETI again

On 7/28/06, Robert wrote:
(...)
> problem with this is that the space between stars has few comet and
> such
(...)

Certainly the density is lower than inside the Solar System, but even
though it is a perfectly adequate density for space habitats. The Oort
cloud is estimated to have *trillions* of comets, separated by
interplanetary-like distances - which means that it would take months
or at most years for a habitat to hop from one to another - and
extending as far as two light years - which means that our own
cometary cloud may touch those of other systems. Also, relatively
recent discoveries regarding brown dwarfs and rogue planets point out
that they are probably far more numerous than stars, and between here
and Alpha Centauri you may find several (or even many) of them (though
in this case they may be light-months from each other).