SETI, where the hell are they?

sonhouse

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15 Aug '15 22:39

moonbus
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14 Sep '15 10:27
"This could be the basis of a science fiction novel."

Imagine life on a waterworld where vision does not evolve, or only useful over very short ranges under water; where creatures navigate by sound or other senses unknown to us.

There is no reason to suppose that intelligence must necessarily develop mechanical inventions or technology as we know it. It might develop 'inner' values instead (something like collective consciousness, or telepathy, telekinesis, or something unknown to us). So they would not be sending RF signals or listening for them either.
DeepThought
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14 Sep '15 15:57
Originally posted by moonbus
"This could be the basis of a science fiction novel."

Imagine life on a waterworld where vision does not evolve, or only useful over very short ranges under water; where creatures navigate by sound or other senses unknown to us.

There is no reason to suppose that intelligence must necessarily develop mechanical inventions or technology as we know it. I ...[text shortened]... something unknown to us). So they would not be sending RF signals or listening for them either.
I've got sympathy for your point, but there are two observations to be made. First, the basic requirement for any inheritable trait is that it should confer a significant survival advantage compared with the cost of having the trait. Big brains cost us a lot and we need a big survival plus from our alleged intelligence to compensate for that. I think that any species not using tools isn't getting enough out of its grey matter.

From the point of view of Earth bound observers extra-terrestrial intelligence is basically defined as species who build radio-telescopes, essentially because if they do not then we haven't a hope of detecting them. This doesn't mean that non-tool using intelligence is impossible, dolphins probably qualify, but that we cannot find a non-technological civilization so we may as well only talk about the technological ones.

Has anyone done a reality check on whether there is terrestrial intelligent life yet?
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14 Sep '15 16:06
Originally posted by DeepThought
Has anyone done a reality check on whether there is terrestrial intelligent life yet?
YouTube
sonhouse
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14 Sep '15 21:23
Originally posted by Shallow Blue
[youtube]buqtdpuZxvk[/youtube]
Einstein said once 'There are only two things I think infinite, one is the universe and the other is human stupidity but I am not sure of the universe'....
moonbus
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15 Sep '15 11:34
Originally posted by DeepThought
I've got sympathy for your point, but there are two observations to be made. First, the basic requirement for any inheritable trait is that it should confer a significant survival advantage compared with the cost of having the trait. Big brains cost us a lot and we need a big survival plus from our alleged intelligence to compensate for that. I think ...[text shortened]... l ones.

Has anyone done a reality check on whether there is terrestrial intelligent life yet?
Big brains do not presuppose opposable thumbs; mechanical tools do. In a waterworld, big-brained creatures might evolve with no thumbs and no survival advantage in mechanical inventiveness.

Searching only for life forms which send RF signals is like looking for your keys in a dark parking lot not where you dropped them, but under the street lamp where the light happens to be shining. It makes sense from the point of view of searching, but not from the point of view of finding.
sonhouse
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15 Sep '15 11:461 edit
Originally posted by moonbus
Big brains do not presuppose opposable thumbs; mechanical tools do. In a waterworld, big-brained creatures might evolve with no thumbs and no survival advantage in mechanical inventiveness.

Searching only for life forms which send RF signals is like looking for your keys in a dark parking lot not where you dropped them, but under the street lamp where the ...[text shortened]... . It makes sense from the point of view of searching, but not from the point of view of finding.
Looking for RF is only the first step. There are also analysis on going looking at certain IR bands which attempt to suss out molecules essential for at least OUR form of life, the big 4, Oxygen, nitrogen, carbon, phosphorous and so forth and stuff like methane, which can come from life or from volcano's but there is this kind of search going on that has nothing to do with RF. We don't have much other choice, now do we? If we saw the possibility of a life bearing planet but it is 4000 light years away, what else could we do but build better instruments to better analyse the signs we already saw at that point in time? We sure as hell wouldn't be visiting a planet that far away in THIS millennium, maybe in a couple thousand years but I wouldn't hold my breath. Science fiction worm holes and such are just a dream and probably always will be.

At BEST if we saw definite life signs on a planet 4000 light years away, we could get there oh, say, around the year 6000. Of course it would be the year 10,000 or so before we could either come back physically or send a laser or RF beam. Not exactly a sure bet.
Shallow Blue
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15 Sep '15 14:53
Originally posted by moonbus
Searching only for life forms which send RF signals is like looking for your keys in a dark parking lot not where you dropped them, but under the street lamp where the light happens to be shining. It makes sense from the point of view of searching, but not from the point of view of finding.
But we're not looking for our keys specifically. We're looking for any keys, for now just to prove that there are people out there who drop keys. For the time being, it makes eminent sense only to look for keys where we can actually spot them.
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15 Sep '15 21:57
Originally posted by moonbus
Big brains do not presuppose opposable thumbs; mechanical tools do. In a waterworld, big-brained creatures might evolve with no thumbs and no survival advantage in mechanical inventiveness.

Searching only for life forms which send RF signals is like looking for your keys in a dark parking lot not where you dropped them, but under the street lamp where the ...[text shortened]... . It makes sense from the point of view of searching, but not from the point of view of finding.
Our tool use goes back of the order of 4 million years. Our species evolution is tied to our use of tools. Opposable thumbs could well be a necessary condition for intelligence beyond a certain level. In a water world dolphins would rule, but would they ever get further than being dolphins?

We can find very strong evidence for life if we see a terrestrial sized planet with a strong oxygen signal. If there is free oxygen then there is a chance of intelligent life, but that is all. We cannot resolve things in enough detail to see anything smaller than a planet. If they cannot send a signal we have no hope of detecting them and they may as well not exist. In interstellar terms we will become intelligent when we built our first transmitter capable of a decent signal strength at interstellar ranges.

The main point is that if there is no electro-magnetic signal then you may as well forget ever trying to detect them. Without a signal there is no find, period.
sonhouse
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16 Sep '15 14:21
Originally posted by DeepThought
Our tool use goes back of the order of 4 million years. Our species evolution is tied to our use of tools. Opposable thumbs could well be a necessary condition for intelligence beyond a certain level. In a water world dolphins would rule, but would they ever get further than being dolphins?

We can find very strong evidence for life if we see a terr ...[text shortened]... n you may as well forget ever trying to detect them. Without a signal there is no find, period.
Not entirely true, there is a major hunt going on in IR bands also:

http://phys.org/news/2015-09-advanced-alien-civilizations-rare-absent.html
DeepThought
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17 Sep '15 07:46
Originally posted by sonhouse
Not entirely true, there is a major hunt going on in IR bands also:

http://phys.org/news/2015-09-advanced-alien-civilizations-rare-absent.html
I don't find the idea of Kardashev type III civilizations particularly plausible. Besides, if they can see the galaxy then it can't contain a type III civilization as they wouldn't be using the entire power output of their galaxy. Looking for unexplained sources of infra-red where there isn't a galaxy might make more sense.
sonhouse
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17 Sep '15 10:44
Originally posted by DeepThought
I don't find the idea of Kardashev type III civilizations particularly plausible. Besides, if they can see the galaxy then it can't contain a type III civilization as they wouldn't be using the entire power output of their galaxy. Looking for unexplained sources of infra-red where there isn't a galaxy might make more sense.
I'm sure that would be on their agenda also.

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SETI, where the hell are they?