Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 5/3/83; site ucbcad.UUCP Path: utzoo!linus!decvax!tektronix!ucbcad!ucbesvax.turner From: ucbesvax.turner@ucbcad.UUCP Newsgroups: net.space Subject: Re: s.e.t.i - (nf) Message-ID: <186@ucbcad.UUCP> Date: Sun, 7-Aug-83 07:14:38 EDT Article-I.D.: ucbcad.186 Posted: Sun Aug 7 07:14:38 1983 Date-Received: Sun, 7-Aug-83 17:32:54 EDT Sender: notes@ucbcad.UUCP Organization: UC Berkeley, CAD Group Lines: 64 #R:ukc:-388700:ucbesvax:8700006:000:3290 ucbesvax!turner Aug 3 23:56:00 1983 Re: Radio emissions as a decades-long blip in E.T. civilizations If we can assume that most technological civilizations go through the same phases in communications (radio to optics), then this might be a clue in itself. By watching the skies for radio activity that lasts only a few decades, we have a fair indication of a civilization that is moving toward the ability to receive and send transmissions. Some major objections to this argument: 1 Would it be detectable against the background radio noise present in the stellar locality? 2 Don't some (non-sentient) objects out these have periodic behavior of this sort (more noise, of a more deceptive kind)? The argument that radio will become passe has some weight, but only for those civilizations that have no interest in or little awareness of space. (Laser technology will have to improve fantastically in order to match radio achievements like the Deep Space Network.) That's not to rule it out. A very large cloud-covered planet with no moon might take a long time discovering that their planet went around the sun rather than vice versa. This might not be a real impediment to technological advancement--although I see strong arguments to the contrary, given the pivotal role of astronomy in the sciences of antiquity. We might be thinking about how important it is to have a moon; or a planet small enough that its size can be measured by the techniques of the early Greek geometers; or having a neighboring planet far enough away, and with moons far enough from *it* (i.e., a "jupiter"), that the finiteness of light-speed can be measured by Galilean (?) techniques; or an orbit large enough to make stellar parallax a reliable technique for determining at least the orders of magnitude involved in stellar distances. Astronomy provided alarming evidence that counter-intuitive perceptions of the universe, based on barely visible phenomena, might have some weight. The persistence and insight of a pitifully small number of people had a staggering impact on history. Astronomy was, perhaps, the first real science; and optics had to be at least empirically understood to get beyond a certain point. It would be a very lucky race to live in a planetary system where all these effects were visible with their native optical equipment (i.e., "eyes".) Good clocks were also important, but this is a little easier. Having materials for the fabrication of lenses seems to be the crucial thing. Without knowing much more than we do about the "average" planet out there, it's going to be hard to come to an assessment of current SETI strategies. The only major breakthrough I've seen is in paleobiology: some researchers have begun to think that spontaneous protein synthesis was a lot less chancy than they originally thought--it just seems to fall right out of the early chemistry of our planet. Perhaps this has bearing on the chances for life elsewhere, and hence, the chances for intelligent life. Another breakthrough is cryogenic circuits, which operate best at temperatures near the background temperature of the universe. Here at Berkeley, they are making Josephson junction receivers which are *very* sensitive. Perhaps good "ears" can be made from these. Michael Turner ucbvax!ucbesvax.turner