I heard the same show, rebroadcast on Friday night. I was waiting outside of SPOC, just hoping those clouds would go away (they didn't). I think one of the most important parts of that discussion--although not fully stressed--was the idea that you basically give up on two-way communication. This is certainly true of light-speed communication as well. As soon as correspondents are separated by a few light years, you really can't have much of a conversation. This is really underlined if you send objects that may take thousands of years to reach a destination. A message really becomes a declaration of "we were here". By the way, the show isn't yet online. But you can get the basic info from: http://www.sciencefriday.com/pages/2004/Sep/hour2_090304.html Michael
I only caught a portion of the show, but NPR's Talk of the Nation, "Science Friday" show this week was on the subject of SETI. The usual suspects were interviewed, but what grabbed my attention was a new concept, for me anyway, that the most ecconomical way to move information across cosmic distances isn't via electromagnetic radiation. Lasers, radio, microwaves, they all lose to....the mail. I didn't get the details but I think the researchers were computer networking specialists who came to the problem through a back door, so to speak. They postulate that it's much more efficient to load up a "mail truck" with data on media and send it on it's way to it's destination star. Yes, timeliness weighs into the equation also, but even so the slow boat wins. Based on that idea, they are now trying to figure out where the mail of advanced beings would be, that we may actually start to look for it! Possibilities include the interiors of asteroids, comets, planetessimals, etc. If anyone hears when this show will be rebroadcast, please post, thanks.