KFL@MC.LCS.MIT.EDU ("Keith F. Lynch") (03/13/86)
From: brahms!desj@ucbvax.berkeley.edu (David desJardins) Jong@HIS-BILLERICA-MULTICS.ARPA writes: >... Most likely, we would encounter an unimaginably more advanced >civilization. I see this kind of statement a lot, and it really seems pretty silly to me. Our civilization is very new compared to the lifetime of Earth. A species from a planet where life started a few percent sooner or evolved a few percent faster might have invented computers and starships while dinosaurs were the most advanced thing on Earth. Where would such a civilzation be today? Lets say we were to pick up a radio signal from aliens at some distant star. Assuming the average civilization capable of sending such a signal lasts for the lifetime of their star, which is around ten to the tenth years, what are the chances that we will have caught them within a century of the beginning of that civilization? If the average civilization lasts ten to the tenth years and broadcasts a message from the time they are first able to build equipment to do so (equivalent to 1940s Earth technology) until their sun goes nova after ten to the tenth years, then the probabilty that a signal is from some civilzation less than or equally advanced as ours is only 4 in a billion. If we were to go exploring, the odds are somewhat better, since we can contact a stone age culture by going there, but not by listening to the radio. But, assuming mankind is one million years old, and that that is a typical pre-technical duration for a species, chances of finding such a stone age culture rather than a culture far in advance of ours is still only one in ten thousand. It is quite mind boggling to me. I think about all the technical progress that has been made in the last hundred years, or even in the last ten years, and try to project ahead. I can think of all sorts of things that might exist in a century, but I really can't imagine what might be around in a thousand years, any more than the average person of the year 1000 could have imagined ARPAnet or even USEnet. Of course it is possible that there are no other technical civilizations, or that they are but they always blow themselves up within a century, or that there is no other life, or that they are maintaining 'radio silence', or that... Who can say? I hope I live to find out. ...Keith
dietz@SLB-DOLL.CSNET (Paul Dietz) (03/14/86)
> Our civilization is very new compared to the lifetime of Earth. A >species from a planet where life started a few percent sooner or >evolved a few percent faster might have invented computers and >starships while dinosaurs were the most advanced thing on Earth. > Where would such a civilzation be today? Right here, if they evolved in or near our galaxy and colonized. I suspect the only ET's we'll ever detect by radio will be extragalactic, and they will have colonized multiple galaxies.
desj@brahms.BERKELEY.EDU (David desJardins) (03/15/86)
In article <[MC.LCS.MIT.EDU].848884.860312.KFL> KFL@MC.LCS.MIT.EDU ("Keith F. Lynch") writes: >.......... > It is quite mind boggling to me. I think about all the technical >progress that has been made in the last hundred years, or even in the >last ten years, and try to project ahead. I can think of all sorts of >things that might exist in a century, but I really can't imagine what >might be around in a thousand years, any more than the average person >of the year 1000 could have imagined ARPAnet or even USEnet. > Of course it is possible that there are no other technical >civilizations, or that they are but they always blow themselves up >within a century, or that there is no other life, or that they are >maintaining 'radio silence', or that... Who can say? I hope I live >to find out. Yes. This is my point. Not only is it possible, but we have no way to estimate the probability. So it seems illogical to "expect" anything. (Although I admit that I "expect" that there is no other intelligent life in this universe, in a rare (for me :-)) defiance of logic). -- David desJardins
KFL@AI.AI.MIT.EDU ("Keith F. Lynch") (03/29/86)
From: hplabs!qantel!ptsfa!gilbbs!mc68020@ucbvax.berkeley.edu (Tom Keller)
Presumably, either they would have detected our emissions, and started
on an exploratory expedition sometime in the past 100 years or so, or we
would be detecting their emissions.
Not necessarily. They may not use the radio spectrum at all, either
because they have found a different spectrum or because they use
fiberoptics or cables for communications. They may use only tight
beams for interplanetary communications. Or they may use light or
some other part of the EM spectrum.
Even if they generate as much radio as Earth, we could not detect
that if they were more than ten or twenty light years away, unless
they were deliberately aiming a strong signal in our direction.
Why would they come exploring if they knew of us? Maybe they aren't
interested. Or maybe they ARE closely observing us without announcing
themselves. Or maybe they are on their way and will land next week.
I don't think any of us are competent to say what their technology
would be capable of, any more than Aristotle could have said anything
reasonable about what computers or the Space Shuttle can do today.
Neither can we do more than guess at their motivations, i.e. whether
they would come here at once if they knew of us.
...Keith