Posted by Belphegorite at 12:04pm Sep 23 '09True, we have life here that doesn't fit within "livable" zones. And over hundreds of millions of years, it hasn't advanced past single cell organisms. We really don't have compelling reason to believe that some extreme sulfophile is more likely to evolve into intelligent life than an organism more resembling mammals. Without evidence of extremophiles even beginning to approach sentience, it's a huge waste of limited resources to look for extremophile civilization before "us" civilization.
As for radio, you've got a point. A much more advanced civilization may be broadcasting communications we are not looking for or cannot receive. On the other hand, a less advanced civilization (say, Bronze Age) wouldn't be able to broadcast radio waves although they would certainly qualify as sentient life. But with the technology we have, radio is still our best option. What else could we use? Sure we may not find certain civilizations, but in theory we should be able to find at least one, if there are any out there to be found.
As for radio, you've got a point. A much more advanced civilization may be broadcasting communications we are not looking for or cannot receive. On the other hand, a less advanced civilization (say, Bronze Age) wouldn't be able to broadcast radio waves although they would certainly qualify as sentient life. But with the technology we have, radio is still our best option. What else could we use? Sure we may not find certain civilizations, but in theory we should be able to find at least one, if there are any out there to be found.
Given what we know of life, it makes sense. - Belphegorite