miles (10/22/82)
Re: mutations, I have not as much background of this field as i would like to have, but anyhowm, is it not possible that the differences in people are caused by some sort of mutations. Perhaps by many many generations of interbreeding. ( physical differences ). This may or not be correct, but i just thought that i would suggest it. Re: intelligence... It is almost inevitable that there are some sort of intelligent life forms out there. But, as said we do not know how to look, or where to look. And if other races developed to high tech. , there is no reason that their developments should parrallel earths, so their ways of thinking and communicating are probably quite different than ours. And if are any races out there that can communicate in a similar fashion, they might just not be interested in trying to contacte other races, or their tech. may not be advanced enough. Perhaps the only way we will ever know is to get out there on our own. For the time being that is not too possible. (excuse the typos) R.S.
REM@MIT-MC@sri-unix (10/27/82)
From: Robert Elton Maas <REM at MIT-MC> At this time I'd like to propose reasons for technological civilizations out-there actually broadcasting radio waves just like we do, even though they evolved differently and have different culture etc. First, most planets of the rocky type like the four inner planets around Sol (the Sun) which are large enough to hold a good atmosphere for evolving life, like Earth and Venus, have differentiated masses of materials so that various mineral deposits exist. Intelligent life on such planets would discover these minerals and discover their properties. One significant property discovered would be that some materials are insulators and some are conductors. Even if commercial distribution of energy in the form of electricity wasn't used, the properties of electricity would be well investigated, including the property of alternating current being radiated from one place and received at another. I think this means radio transmission would be discovered and developed as a scientific curiosity at the very least. A technological society may be treated somewhat as a large manufacturing plant with a large computing system (the brains of the creatures in the society being the CPUs). Any maufacturing/computing needs communication. In the search for better communication, all sorts of media would be investigated. Just as we on Earth are experimenting with communicating via all wavelengths of electromagnetic radiation from very-low-frequency radio thru ultraviolet (x-rays and gamma-rays aren't used because they are too dangerous) as well as acoustic waves and even thinking about maybe gravity waves someday, I suspect alien civilizations would investigate them all too. In a natural planetary environment various wavelengths have various advantages and disadvantages. Some bounce around between ground and ionosphere to provide better than expected long-distance communication albeit not reliably. Some pass thru the atmosphere thus are effective for satellite-based communication. Some bend around the planet to provide reliable medium-range communication. Some are line-of-sight to provide secure (private) and reliable communication. Some pass thru buildings or go around them smoothly to provide good local communication. Some have such short wavelengths they can be sent via conduits such as waveguides or fibers. -- I suspect the whole electromagnetic spectrum would be used for various purposes. Chances are lots of broadcast-style communication (more efficient than directed-communication when a mass-audience is desired, such as for political brainwashing or civil-defense bulletins) would happen to leak out and be detected from other planets around other stars. We should simulate radio conditions on various possible planetary atmospheres, starting with known ones in our own Solar system, pick wavelengths that are likely to leak out, and listen for those wavelengths. For planets like our own, we simply use ground-based SETI receivers tuned for what passes thru our own atmosphere. For planets unlike our own we might need space-based SETI receivers to catch stuff that leaks out of their atmospheres but not into ours. Any weak links in that chain of argument in favor of radio-based SETI? It's sort of a straw man to knock down, not something I'm very convinced of, but I'm leaning in that direction and I'd like to hear any rebuttal or amendments.
CSvax:Physics:els (10/27/82)
One weak link that I can think of is that general broadcasts usually
are fairly weak( on an interstellar scale), and most would be washed out
in the background clutter. Arguments similar to yours have been used to
arrive at the idea of listening around the "water hole". The idea of
listening for random leakage is OK, though if civilizations are fairly
dense in distribution. It has the advantage of giving a "peeping tom"
sort of view into the society(ies) on the other planet. Broadcasts that
are beamed out intentionally are certainly more likely to be censored w.r.t.
accidentally giving a potential enemy vital info.
els[Eric Strobel]
pur-ee!pur-phy!els