🚀 go-pugleaf

On 17 Aug 2000 02:53:13 GMT, "Dranith"
<name_in_from_line@crushed_type_of_fabric.what_you_catch_fish_with>
wrote:

(snip)

>>Still, I question the need as a recent article in SciAm
>>indicated that well over half the space where we might
>>reasonably expect ET to be found has already been
>>searched and found empty.

   We cannot conclude that the space where no signal is found is
necessarily "empty".

(snip)

>Why do we need evidence to believe that Terra isn't the only planet
>that life exists on?  Shall we instead arrogantly presume that only
>this planet, this sun, this galaxy, could possibly hold life, that
>not one single other planet in the universe could ever develop a
>form of life that's at or above the level we've reached?

   SETI is not looking for life per se, it is looking for a radio
civilization. Life may be ubiquitous -even intelligent life could be
an extremely frequent event if you consider the entire universe. But,
there may not be any other radio civilization "currently" broadcasting
in the galaxy. We are looking for a civilization in a roughly two or
three century long phase of a several billion year long development
process. In the history of the entire universe very many such
civilizations could have arisen and all have been millions, hundreds
of millions or even billions of years out of sync with us and perhaps
very far away. Finding one within "earshot" could be highly unlikely.
   Plug some wild guesses into the Drake equation. Using "reasonable"
values for the parameters you can get estimates for the expected
number of radio cultures that range from many thousands "currently" in
the galaxy to way, way less than one (meaning we are quite a fluke).
IMO, the lack of SETI success so far tends to rule out the really big
numbers.


ATG