Why is there SETI?

24 hours a day? When SETI was using the acrebelo (?) telescope it was like 3 weeks out of the year in a tiny radius. Despite the fact many smaller telescopes would have been trying the same thing throughout a year, how much of the possible input were they searching?

This thread asks the purpose of SETI and I believe the current technology of SETI is pointless in achieving a goal, but is vital as a first stepping stone. We believe we are special, but I doubt that is the case. Is this really as good as it gets? Certainly people posting here think that sending out radio signals in straight lines at the speed of light is as good as it gets...

 

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This thread is based on the postulate that the SETI has little to no chance of being successful. Is there an evidence to that? Because if there isn't, then there is no use of discussing such matters...

 

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Send a united message to ET from all humans as one power and see the difference. But alas USA dosent like UN in power.

 

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Much on the contrary. US OWNS UN.

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I think the real question is: Is ETI (if they're out there) doing the same thing we are in search for SETI? Very doubtful and probably not.

 

TruthSeeker:Are you aware of the vastness of the universe, the speed of light limitation on electromagnetic signals, and the possible strength of electromagnetic signals from many light years distance?

It is obvious that practical 2-way communication is just not possible without some astounding revolution in the laws of physics (not expected by anybody). Think about trying to converse with a ET 20,000 light years away. You get a message and reply. 20,000 years later the ET gets your reply and sends another message. Round trip is 40,000 years. The only meaningful method of communication is to send what you think might interest him and let him do likewise, with neither ever expecting a conversational interchange.

Even with a very tight beam, the signal strength drops off drastically in 20,000 lights years. I see no reason to expect more than one intelligent civilization per galaxy, requiring us to contact an ET that is millions of light years away. Even if there were an ET in our galaxy, he is likely to be obscured from us by stars and dust clouds.

BTW: One ET per galaxy seems like an optimistic estimate to me.

Our signals could not be seen by an ET in another galaxy. To communicate from galaxy to galaxy, you would need technology capable of causing a star to pulse morse-code like signals.

I have yet to see a convincing argument that ET’s exist, although I think a few might. I have yet to see even a slightly plausible argument that we could receive signals from an ET.

 

Dinosaur, what a depressing estimation you have of it all. You say that we are probably the only intelligence in a galaxy of some 400 billion stars, and that galactic communication with a time lag of 20,000 years is as good as it gets.

Are you even in a position to be so sure of yourself? We do not yet have sufficient intelligence or technology to become a space conquering species, but don't you think that when and if we do, that we will have a much different view of this whole topic?

I imagine if this was 1950 you'd have a similar pessimistic view of going to the moon.

 

Of course. We all know there is no intelligent life in this universe.....

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And if there is, they are most likely using something that we cannot yet detect.

 

Yes. That's enough to say that there's enough space and enough stars out there to make life not only possible, but even probable. As fars as communications go, are you aware of the various new discoveries in quantum physics in the past years? Our technology has lots of time to improve. We have just discovered computers, and look all that we did with it! It doesn't take very long to discover new ways of using the laws of physics...

Or on our knowledge of the laws of physics. I remember just a few years ago, the estimated travel time to Mars was in a matter of years. Now, with new technology, we can do it in 3 months.

Why aren't there ETs in Alpha Centauri? It's around 4 light years away. It's better to start trying there then other far away places.

You are also assuming that there is no way of breaking the speed of light.

It is an extremely pessimistic one, given the fact that the vast majority of stars are just like the sun, and the avaiability of resources is far greater then we had thought before....

Sounds cool. Let's start working on it.

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Wait! Maybe that's why some stars pulsate!

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I don't put faith in the "stepping stone" argument - SETI will become effective only when the technology to make it so is available. At this point, it is not, and whether we flounder about with ineffective methods until then won't influence the eventual prospect of success, when we have the right equipment.

There's no conclusive evidence either way. All we know is that SETI's ability to detect signals is akin to Stevie Wonder's knack for catching fly balls. But given a lack of an alternative, it's either SETI or nothing - and I can guess which of those two is less likely to pay off.

The pace of business at the Galactic level is obviously that of a snail's. But even a snail's pace isn't the same as no pace at all. If there is an ancient ET out there (say 1 billion years old), then they will be acclimatized to this fact - for they will have been conducting this way since time immemorial.

For us, with our genetically un-altered life spans of only decades, this makes this entire debate somewhat moot. In fact, by process of elimination, it can be easily demonstrated that the only possible situation we should be seriously interested in investigating is that of the Galactic Zoo. Only in this circumstance is there the prospect of any interaction at all happening while any of us are still alive.

One ET per galaxy is probably the least likely result possible in the universe. Either a galaxy will be hostile to life, or it will not. This implies either many civilizations or none at all, but almost, if never, just one.

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I'm not so self-assured. To my mind, a number of those hillbillies from the 1950's and 1960's must have been rustic military geniuses, because the objects they were photographing appear to have exhibited the characteristics of stealth technology - 20 years before they could have known it existed,

"Paw, why not just photeeshoot a hubcap like'n Couter did?"

"Becaus'in a hub cap won't defeat radar emissions in the I and J bands, Billy."

The term "convince" describes complex biochemical processes within a single human being's brain. But ET will or will not have come into existence by way of such neurological trickery, rather his birth will be due to fortunate circumstances surrounding one of the 100 billion stars out there. Once we've gone to all of the Galaxy's star systems and not found him, then I will be certain ETI does not exist in the Milky Way.

The laws of the universe are not subject to negotiation - they are absolute. This means that, even at the point where our science knows how to technically exploit every last possible "trick" in the entire handbook of grand unified physics, we will still be almost certainly be moving about at less than the speed of light. We may indeed become a "space conquering species", but we will do so at a somewhat pedestrian pace...

I doubt he would have. At least in the moon's case someone could point to technology like the A-4 (V-2) rocket and come up with a plan to get there that was at least feasible.

 

So far man has stepped on the moon and put some robots on mars and hit an asteroid with part of a scientific probe. It took nearly 60 years of big-time effort and billions of $$$ to do that. Chances are in the next fifty years or so man may walk on the surface of Mars and possibly establish a moon base. But in terms of space travel beyond the solar system? I'd almost bet you that in the next 200 or 300 years, man is still trying to cruise around in the solar system. Forget about man traveling to the stars and having breakfast with ET. Maybe he will in your dreams, a science fiction novel or Sci-fi movie. The only way man is going make contact with ET, is if ET contacts man first and then it will only probably be by accident. After that, all bets are off.

Okeydoke

 

KennyJC & TruthSeeker: You read too much SciFi, and do not do enough critical analysis. You imagined wrong when you said the following.

In the middle 1940's I was well aware of Goddard’s (? spelling) 1920's experiments showing that multi-stage rockets were feasible. At that time, I expected us to be capable of going to the moon and planets in our solar system within my lifetime. I was not sure that anybody would be willing to spend the money and other resources to do so, but it was obvious that the technology would soon be available.

I love SciFi as well as enjoying studying at the frontiers of science. I try to separate the two.

BTW: I would be very happy for us to be visited or contacted by an ET, and would not mind having my views proven to be erroneous.

As far as I know, the SETI people and others have discarded the possibility of life on planets orbiting the stars within 50 or so light years of the Earth. Forget about Alpha Centauri and other nearby stars.

I think I have some reasonable evidence to support my pessimistic views.

For 50 or more years, I have seen all sorts of estimates of how many intelligent civilizations are likely to exist. Most of them seem to be speculation unsupported by any worthwhile analysis. I have only once seen a good analysis of this question. To make that analysis a bit more understandable, I have considered the life of the solar system as 1000 days rather than about 4.6 billion years. Big numbers are hard to grok. I am working from memory, so the figures might be a bit off, but there are correct enough to give you the idea.

• 1000 Days (4.6 billion years) ago, the planets of the solar system formed after a long period of gravitational collapse from a cloud of interstellar dust.
  
  
• 804 days (3.7 billions years) ago, the first life appears. It occurred here almost as soon as conditions were suitable for its existence. This strongly suggests that life is very common in the universe, assuming a large number of suitable planets (seems like a reasonable assumption).
  
  
• 54 days (250 million years) ago, the first dinosaur-like creatures appeared. Note that in the history of the Earth, it took a long time for a successful large land animal to appear. There is good reason to assume that fish, amphibians, and flying creatures will not develop a tool making technology.
  
  
• 14 days ( 65 million years) ago, the dinosaurs became extinct. It is believed that a cosmic disaster wiped them out (either an asteroid or extreme volcanic activity). They survived for almost 200, million years without evolving intelligence, strongly suggesting that intelligence is not necessary for evolutionary success. Were it not for some cosmic fluke, they might have survived until modern times.
  
  
• 10 hours (2 million years) ago, the first man-like ape )Homo Erectus) appears.
  
  
• 2 hours (500,000 years) ago, early Homo Sapiens appears.
  
  
• 40 minutes ago (130,000 years) ago, modern man appears.
  
  
• 3 minutes (10,000 years), early civilization starts replacing hunter gatherer cultures.
  
  
• 2 seconds (100 years) ago, modern technology gets started.

The above does not provide much evidence that technological cultures are an inevitable result of evolution. It could be that intelligence is a lucky accident. The above does strongly suggest that life will form whenever conditions are suitable, and that more complex life forms will evolve once the simple single celled creatures get started.

Now consider then and where the earliest intelligent species might have occurred.

The universe is believed to be about 14 billion years old, and is further believed to have consisted almost entirely of hydrogen and helium shortly after the big bang. The first generation of stars could not have planets with oxygen, carbon, silicon, and all the other elements required by living creatures. Those elements were formed during the explosive end stages of stellar life cycles. After being scattered to form large nebulae or clouds of interstellar dust, gravitational collapse results in the formation of solar systems with elements other than hydrogen and helium.

The first solar systems with the necessary raw materials would be 4th generation or maybe much later generations.

The first solar systems with the raw materials for life could not have existed for perhaps 1-2 billion years after the big bang. This is a WAG on my part: I have never seen a credible article which made an estimate of the earliest possible time for the existence of such a solar system. Maybe 3-4 billion years is a better estimate. I do not think that the first could be much earlier than 1 billion years after the big bang.

The above suggests that intelligent life could not have formed earlier than about 6-9 billion years after the big bang: 1-4 billions for the formation of the first suitable solar system and another 5 billion or so for the intelligent life to evolve. This assumes that one of the first solar systems with the necessary raw materials also fulfilled other requirements of living creatures.

Note that many solar systems with the necessary raw materials are likely to be lacking other necessary conditions for life. Within a solar system, there must be a planet not too close and not too far from the central star. In our solar system, the correct distance is probably a bit farther out than Venus and not much farther from the sun than Mars. Note that massive stars burn out in less than 2-4 billions years, not lasting long enough for evolution to work it smagic.

Note that a suitable solar system must be properly positioned in its galaxy. Nearer the center there is too much radiation and too many rapidly moving stars making astronomical catastrophes likely. Farther out than our solar system, the dust clouds do not have enough of the elements other than hydrogen and helium.

Considering all of the above, we could very well be unique in our galaxy at this time, with other technological civilizations yet to develop in the future. At best, we are likely to be one of just a few in our galaxy.

Assuming the existence of other technological civilizations, it is still unlikely that we will pick up any signals from one of them. It requires them to send out a tight beam in just the right direction in a correct time frame. Signals originating 50,000 years ago from 100,000 light years away will not get here for another 50,000 years. Signals originating 100,000 light years ago from a position 50,000 light years away passed by 50,000 years ago.

 

As it should be.

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Depends on what sci-fi means. If man circling the globe is a fact today and was one day science fiction then yes I suppose it is for the moment science fiction when we talk about the possability of discovering life elsewhere.

Perhaps by making that example of the 1950's, I over-estimated even your assurance that things are really unlikely and impossible. But I think you sort of made my point when you said you believed in it once the technology and the know how was put in place.

I don't believe it is science fiction because if us humans stick around for a really long time, I'm talking millions, maybe even billions of years, then estimations (pessimistic or optimistic) won't come into it. Will a descendant of Seth Shostak still be tweaking his radio in 1,000,000,000 years time? I anticipate a reply saying "Oh but we would have long become extinct because Earth can't sustain us for that long and colonizing other planets is impossible!"

I'm afraid I can not come up with many facts to prove the likely existance of ETI in our galaxy, but I guess there are between 100-400 billion stars in this galaxy and so much has happened around just this one star. It is not impossible that something similar can't happen elsewhere and I believe if there is ETI in the galaxy, given time (lots of it) I think it's likely we will find it, wether it be with radio signals or a super duper alien finder device.

 

KennyJC: I see only opinion, no analysis in your last post. You could at least provide some of your basic assumptions.

Do you assume that once life exists, the evolution of intelligence is inevitable? The history of the Earth does not provide much basis for such a belief.

Do you assume that systems with more than one star are suitable for the development of life. Are you aware that many stars are part of binary systems, and some are part of trinary systems? I have no opinion on this particular issue, but suspect that systems with more than one star might be not be stable long enough for evolution to occur.

Have you considered what percentage of stars last long enough for evolution to take place?

Have you considered what percentage of stars are properly positioned in their galaxy?

Have you considered what percentage of solar systems have a planet at a suitable distance from the central star?

 

All I see is opinion from you too. Carl Sagan says 1 million civilizations and you say we're probably alone.

Well we did appear "2 hours ago" didn't we?

Check out the article in the 'planets around alpha centauri' and see what you make of that. By the way what percentage of stars in the milky way are part of a binary system?

I was under the impression that such stars with short lives were a minority.

Again this notion that this and that are impossible. I'm not denying the theory behind it, but there are still billions in the comfortable 'suburbs'.

Well since our measley technology doesn't allow us the luxury of seeing many planets, who can say one way or another. It's a reasonable guess though that there are more planets than stars in the galaxy which then if true makes the number of 100/400 billion stars seem small. It's easy to forget the huge numbers involved when looking at all the contributing factors that resulted in intelligent life around this planet. Afterall, if Mars was a bit bigger it could have probably had more significant life around today (although it looks likely life exists on Mars anyway). Imagine that, two neighbouring planets with life...

 

We have to try. No matter what assumptions we make using the knowledge that we have, we actually don't know if there are zero other civilizations out there, or if there is one near every star. One could start emitting radio waves next week, or a dozen. There was a first radio transmission from Earth, and it was only a little over a hundred years ago. Look how far we came.

We really just don't know how "likely" this is, either.

 

The reality is; 'We haven't come that far yet'. If we're lucky, if we're real lucky, maybe in the next 200 or 300 years, man may make a voyage to Alpha Centauri, but even that is very optimistic. Wars, supervolcano eruptions or a collision with an asteroid may take care of that possibility. Don't bet on space travel to other stars and contacting ET anytime to soon.

Okeydoke

 

I dont intend to change the topic, but the reason or such other reasons may be that ET considers us not eligible to be contacted. I mean think about, humans are so primitive, They are not united, full of wars, Harrased by USA. No UN in power , etc.

 

It seems just about everyone who is involved in the SETI programs 'expects' a message to be recieved from ETI in their lifetime. Those individuals that I know who participate in SETI are strangely attracted to the notion that ETI exists in our galaxy and probably in all the others too. If that were the case, the universe would be full of messages and radio signals coming and going in all directions. Relatively easy to pick up and detect I imagine. However, so far, such is 'not' the case as SETI has found out. It's entirely possible that we may be the only ETI in our galaxy and even more remote is the idea, that we 'may' just be the only ETI in the universe. ETI could be a very, very rare entity in the universe. Just maybe there are only one or two ETIs living in the galaxy at any one time together. The others, if there were any before, have come and gone. Maybe the same possibility applies for the rest of galaxies in the universe too. Who knows for sure? Bottom line is; So far 'no' confirmed messages from ET!

Okeydoke