[X] My Assistant

[Toymaker]

Seti always worked on its own assumptions, and perhaps it is ironic that the only civilization that we now(ours) isn't going alongside these assumptions. We aren't sending dozens of high energy signals to other stars, as SETI is hoping other's do. Of course if I am wrong, please correct me. Our own normal transmissions aren't detectable very far, and any other civilisation on equal scale wouldn't be detactable also.
Interesting link:
http://www.faqs.org/faqs/astronomy/faq/part6/section-12.html

It should be apparent then from these results that the detection of AM
radio, FM radio, or TV pictures much beyond the orbit of Pluto will be
extremely difficult even for an Arecibo-like 305 meter diameter radio
telescope! Even a 3000 meter diameter radio telescope could not
detect the "I Love Lucy" TV show (re-runs) at a distance of 0.01
Light-Years!

It is only the narrowband high intensity emissions from Earth
(narrowband radar generally) that will be detectable at significant
ranges (greater than 1 LY). Perhaps they'll show up very much like
the narrowband, short duration, and non-repeating, signals observed by
our SETI telescopes. Perhaps we should document all these
"non-repeating" detections very carefully to see if any long term
spatial detection patterns show up.

Another question to consider is what an Amateur SETI radio telescope
might achieve in terms of detection ranges using narrowband FFT
processing. Detection ranges (LY) are given in Table 2 assuming a 12
ft (3.7 m) dish antenna operating at 1.42 GHz, for various FFT
binwidths (Br), Tsys, snr, time bandwidth products (twp = Br*t), and
EIRP values. It appears from the table that effective amateur SETI
explorations can be conducted out beyond approximately 30 light years
provided the processing bandwidth is near the minimum (approximately
0.1 Hz), the system temperature is minimal (20 to 50 Degrees Kelvin),
and the EIRP of the source (transmitter) is greater than approximately
25 terawatts.

As to other advanced civilisations, it was already pointed out, that they wouldn't need to contact other potential ones by radio, as they could detect habitable worlds and send probes. The differences between point of evolution of civilisations in time would make any radio signals sent irrelevent anyway.
Also as pointed out advanced civilisations would(again like us) use more and more efficent ways of communication, making radio obsolete. I am also sceptical about the proposed vision of Kardashev civilisations, they seem more like the naive visions of early XX century regarding progress of humanity, with humans changing the flow of rivers, creating seas and destroying mountain ranges(offside remark: these was very popular vision on SU so maybe Kardashev was influenced by it). I would be wary of thinking that megascale engineering is the way of the future. Opposite could be true(disregarding energy sources of course).
All in all SETI is a very overhyped project in my opinion, which never had much chance of success and was very naive in its assumptions. The bad side is that it started to live with its own life and is believed to be by many as some measure of status of universe and our position in it. As to my personal opinion I do think life is rare, and intelligence is unique. If they are civilisations capable of technological advancement, they are likely milions of years apart from us and thus to large degree incomprehensible to us, if not even uncaring about our existance.

[Marz]

Seti always worked on its own assumptions, and perhaps it is ironic that the only civilization that we now(ours) isn't going alongside these assumptions.
....
All in all SETI is a very overhyped project in my opinion, which never had much chance of success and was very naive in its assumptions. The bad side is that it started to live with its own life and is believed to be by many as some measure of status of universe and our position in it. As to my personal opinion I do think life is rare, and intelligence is unique. If they are civilisations capable of technological advancement, they are likely milions of years apart from us and thus to large degree incomprehensible to us, if not even uncaring about our existance.

Well, this is just at the crux of the whole purpose, isn't it? All we have now to work with are opinions and unfounded assertions. We don't know how prevelant life is, much less sentient life, much less technologically advanced civilizations. Life on Earth does not show some inexhonorable evolutionary pathway towards sentience.

But what is known is the dataset is very, very, very large. We can speculate all we want about Rare Earths or that tech civs go from noisy radio to quantumn communication in less than 200 years, or whatever...

The purpose of SETI is to stop speculating and look. All SETI has shown to date, is that our galaxy isn't riddled with very strong radio broadcasts. But without even searching, we can't begin to place upper-limit boundaries on the Drake equation.

In my opinion, SETI is like a scientific lottery. There is a small chance that it will make the most profound discovery in our history. Considering how relatively cheap it is to buy a ticket, and how interesting the search is, I don't see why we shouldn't be trying... and I certainly can't argue against how the search to date has been a 'waste' either. After all, we know there is at least one civilization in this galaxy spewing radio waves outward.

Considering how TPF has been cancelled, all we can do is keep throwing darts in the dark and see if one sticks. To paraphrase Teddy, "It's better to try and fail, than to sit in the dark second guessing everything."

[Guest_Richard Trigaux_*]

Interesting remarks, Marz and Toymaker. Some replies in random order:

-The idea as what intelligence MUST be unique is not a scientific idea, it rather arises from an old catholic dogma. Today we simply don't know and are still far of knowing.

-The ideas as what other civs MUST be bad, uncaring for us or ununderstandable for us also seem to arise from pessimistic philosophies, not from a reasonable speculation about what is possible. And really many things are possible...

-The SETI started with a simple view: a radio telescope like the one at Arecibo could dialogue with its peer at hundreds of light years. At this time, Earth was teeming with powerfull radars and radio stations, some sending megawatts. Unforeseen were the more recent evolutions: internet and cable replacing air broadcast, stealth military radars... So in a way you are true.

-Today SETI did not detected a Kardanchev type III civilization. But it would not detect earth at more than one light year, so it is clear that we cannot yet assert that there are no radio technology in the skies, and still by many orders of magnitude. It is a bit like if the seach on gravity waves was abandonned in the 1970' because the first detectors at this time found nothing. We learned since that these detectors lacked more than ten orders of magnitude in sensitivity. SETI is still in the state of gravitationnal search in the 1970'...

-If SETI really finds nothing, so it will be anyway a tell tale experiment, like the Michelson Morley experiment. The Michelson Morley told us that there was something completely wrong in our understanding of physics. It was a very productive experiment. Similarly te SETI already told us that there is not such a nighmare as a Kardanchev type III civ, or a Starwars world.

-Toymaker I liked your analysis on the Kardanchev classification. Nothing tells us that we must evolve that way. It is even more and more apparent that ecological or social disorders would forbid us the way of mega-technology.




The Fermi paradox could have many solutions. the most common is that we would be in a kind of "zoo". I don't like this one too much, but I can tell some other explanations which are much less common, but being still scientifically valid:
-There is simply no mean to travel into interstellar space, no quantum communication, etc... (or there are such things, but they need first to establish a base on Earth).
-ETs are roaming all the space routes, but no civ, whatever they are highly compassionned sages or evil scruppleless conquerors, will never attempt a landing on a planet already infected with its own life, simply because they would be sick from this.
-Civs find other ways to evolve and achieve happiness than with technology.
-UFOs are often invoked as evidences of ETs visits, even by some SETI specialists. But this phenomenon is much more ancient than SF movies, and it happens that in ancient times it showed rather mythological scenes than SF scenes. For this reason and many others, I strongly suspect that UFOs are not ET spaceships.

[Bob Shaw]

I strongly suspect that XYZs are not ET spaceships, even if we consider them as a real phenomenon.

Richard:

I suspect that's a three-letter word which we should avoid using here, lest Mr Google leads certain parties in this direction! Not to mention the Wrath of Doug!

Bob Shaw

[Guest_Richard Trigaux_*]

Use a parental control if you don't like it. .

[Toymaker]

I also would like to ask if anybody knows the an answer to the following issue(please do mind that I am no scientist ). If SETI worked on assumption that they are searching for Kardashev type civilisations engaging in high megascale construction and energy utilisation have they ever considered searching for signs of such civilisations other then radio ? Of course this is highly SF to the average person, but If they were assuming radio transmissions on such scale, why not search for Dyson Spheres, infrared signs of civilisations around other stars using high energies, megascale constructions etc ? After all It would fall into the same activity expected from such civilisations, only sounding more fantastic then radio signals SETI was searching for.

[dvandorn]

Ah, but what would such megastructures look like from interstellar distances? Dyson seheres would block out the light from the stars they encompass, so unless you see one being completed (i.e, the star just goes out), we wouldn't see them in the first place. Gravitational effects that would say a star should be in a particular place, but is not visible, could be explained by a dark neutron star or a black hole. And, again, there are other, far more likely explanations (dust rings, planetary nebulae, etc.) for megastructures that only partially or occasionally block the light from stars.

I also seriously doubt that anyone at our present level of civilization could even begin to model what types of ultraviolet, infrared, microwave or even X-ray signatures to look for that would indicate manipulations on a Kardashev scale. And such manipulations are probably going to look an awful lot like similar natural processes that end with the products these proposed engineers are trying to achieve. (In other words, if you're building planets, you're probably creating a situation that looks, from the outside, a lot like natural planet accretion. The only thing that might be different from a "natural" accretion scenario would be the timeframe, and we don't have a good enough handle on how long the natural processes take to be able to tell, from interstellar distances, that anything we see is happening at an accelerated rate.)

So, while what you say makes sense, we really don't have either the detection capability to see such things definitively, nor the intelligence or the context to be able to nuance the tell-tale signs we need to be looking for.

-the other Doug

[ljk4-1]

I also would like to ask if anybody knows the an answer to the following issue(please do mind that I am no scientist ). If SETI worked on assumption that they are searching for Kardashev type civilisations engaging in high megascale construction and energy utilisation have they ever considered searching for signs of such civilisations other then radio ? Of course this is highly SF to the average person, but If they were assuming radio transmissions on such scale, why not search for Dyson Spheres, infrared signs of civilisations around other stars using high energies, megascale constructions etc ? After all It would fall into the same activity expected from such civilisations, only sounding more fantastic then radio signals SETI was searching for.

To repost a link to a paper I had listed earlier in this thread:

http://arxiv.org/PS_cache/astro-ph/pdf/0506/0506110.pdf

Fermilab is conducting searches for Dyson Shells using the data from IRAS:

http://home.fnal.gov/~carrigan/Infrared_As...ilab_search.htm

Also see Robert J. Bradbury's Matrioshka Brains:

http://www.futurehi.net/docs/Matrioshka_Brains.html

The ultimate point is, if we don't look, we won't find anything, and not to
search is the antithesis to scientific research no matter what the subject.

For those who are opposed to SETI, I always ask, what is your
alternative? Is this preference/desire that Earth be the only place
with life in the Cosmos a fear of beings far more powerful and
intelligent than we?

Are we still operating under the primitive, ancient fear of anyone or
anything different from us must be a threat to our existence? Perhaps
I expected more open-mindedness from people who are otherwise
deeply into the exploration of alien worlds.

When we have explored a good chunk of our galaxy and found only
lifeless worlds, then we can begin to wonder just how many other life
forms are out there. We are still far too inexperienced to say that we
are the only intelligent beings in a Universe of over 50 billion galaxies
with their 70 septillion stars.

[Toymaker]

Dyson seheres would block out the light from the stars they encompass

Oh I thought about infrared.
Looked into it on the internet. Seems some basic searches were made, but like you said, difficult to distinguish from natural sources.

http://home.fnal.gov/~carrigan/Infrared_As...nomy_master.htm


http://home.fnal.gov/~carrigan/Infrared_As...er_searches.htm

For those who are opposed to SETI, I always ask, and what is your
alternative? Is this "desire" that Earth be the only place with life in
the Cosmos a fear of beings far more powerful and intelligent than we?

I am not opposed to SETI, I am opposed to giving it so much importance and somewhat "holy" status as the final verdict on our position in universe(the often almost religious-like character of statements by SETI enthusiasts doesn't help ). It is really irritating to see many SETI scientists somewhat boldly stating verdicts on why have to aks ourselfs "are we alone" and go on about radio contact, without acknowledging to the public that the chance of actually finding something with SETI are very, very minimal. Often elaborate theories are made on possible development of civilisations without adressing this issue.
Personally I believe that finding extrasolar planets is more rewarding, but that's just my opinion.

[ljk4-1]

SETI is obviously not given the importance you claim it to have by others,
otherwise it would have a lot more funding and a lot more prominence in
the public's mind.

You must be reading some rather old SETI literature, as most SETI scientists
are not quite so "bold" about their pronouncements of finding alien life as
they may have have once been. Now that we know there are no powerful
signals being broadcast in our galactic neighborhood (at least by the methods
we can detect) - thanks to SETI - scientists are being more cautious and also
trying find them via other methods, such as Optical and infrared searches
for Dyson Shells.

Modern SETI started in 1960 with Project Ozma, but only in the last decade
has it really begun to get the technical and financial attention it is needed to
become any kind of a real success. Certainly trying to find out if there are
other intelligent beings in the Universe counts among the highest endeavors
for science.

No real SETI scientist thinks SETI will give us the ultimate verdict on intelligent
life elsewhere, but it does have a real chance of finding at least a few other
species, now that the searches are finally starting to go beyond a few sporadic
and temporary efforts.

And until the day comes that we can start sending probes out to other star
systems, SETI will be our best bet for finding them.

Looking for microbes in our solar system, finding alien planets around other
suns - it all adds up to the same goal.

[Guest_Richard Trigaux_*]

Toymaker, an ever good policy when we search infos on a topic is to seek these infos at the source. In the instance, on the SETI website, not into bad science review which confuse SETI with some new age cult. Of course SETI searchers may have various opinions, and some may even have psychological defects (like everybody else) but I think we can say that, globally, the SETI search and the SETI community are good science. It is a bit incredible that, whatever we speak of medecine, astronomy, physics, electronics... people reply us about medecine, astronomy, physics, electronics... but when we speak about exobiology, we are replied psychoanalysis. It is as if, when Steve Squires presents us results of the Mars rovers, we asked him if he has a super-ego or a dogmatic vision of Mars. This is basically a stupid prejudice which should be absent on a science forum, but which has yet parasited half of this thread. THIS SHOULD STOP.

About your reflexions:

-The Kardanshev classification has three scales: type I: us. Type II: all the energy of a star. Type III: all the energy of a galaxy. What you was speaking about was type III. Type II and type I ar still far from reach of SETI. The diagram of the SETI results should answer your question: a type III should be detected wherever into the galaxy (none was found) a type III at maybe hundreds of lights years (none was found at this distance, teling us they are not common) and a type I at... less than 1 light year. None was found, but in this situation it is a bit unconclusive, don't you think so?

-Dyson spheres should radiate the same energy that they receive from their star, but at a much lower wavelength. At a rough guess the "surface" of a Dyson sphere should be somewhere between 0°C ant -50°C. So they may appear at "cold stars". As far as I know, astronomers never purposely searched for such objects, but they actively searched for infrared emitters into clouds, where stars form. There was also systematic sky surveys to try to peer through dense clouds. Unfortunately Dyson spheres would be confused with other stars. But I think that if there was a Dyson sphere nearby, it would be mapped for long, if not identified.

-Dyson spheres could also appear as "machos" in the search for dark matter. But again, we would be unable to distinguish them from a cold white dwarves. ("Machos" are star-like objects, supposed to form the bulk of the dark matter. Let us a bit speculate wildly: the dark matter would be formed of billions of Dyson spheres... ooops)

-About the models used by SETI (how civs may communicate, what by-products the emmit, etc...) there was in the beginning of SETI an enthusiasm on such naive "scifi" models as the Kardanshev models, which are now widely questionned. So some are theorizing on other wavelengths, other communication means, other purposes, other evolutions than the Kardanshev models. But this is still highly speculative and it is difficult to come with a testable assertion. So SETI is still doing what we know to do: exploring the radio spectrum (a task far from finished) and it begins to search for laser communications.

[ljk4-1]

William Edmondson has created a setiblog for updates and information on his
research into pulsars (rapidly rotating neutron stars) as beacons for SETI.

The Web site URL:

http://www.cs.bham.ac.uk/~whe/setiblog.html

From the introduction:

SETIblog

This blog is about the analysis of 3TB of radio-telescope data collected at Arecibo as part of a Search for Extra-Terrestrial Intelligence using a new targeting strategy reported in a journal article. The processing started shortly before Christmas 2005. Exploratory work of familiarization with the data format and some processing algorithms will eventually be followed by detailed reports on the data for each star studied.

The Web site has links to his papers on the subject as well.

[ljk4-1]

A Scheme for Targeting Optical SETI Observations

Seth Shostak (1) and Ray Villard (2)

(1) SETI Institute, Mountain View, CA

(2) Space Telescope Science Institute, Baltimore, MD

Abstract

In optical SETI (OSETI) experiments, it is generally assumed that signals will be deliberate, narrowly targeted beacons sent by extraterrestrial societies to large numbers of candidate star systems. If this is so, then it may be unrealistic to expect a high duty cycle for the received signal. Ergo, an advantage accrues to any OSETI scheme that realistically suggests where and when to search.

In this paper, we elaborate a proposal [1] for selecting regions of sky for intensive optical SETI monitoring based on characteristics of our solar system that would be visible at great distance. This can enormously lessen the amount of sky that needs to be searched. In addition, this is an attractive approach for the transmitting society because it both increases the chances of reception and provides a large reduction in energy required. With good astrometric information, the transmitter need be no more powerful than an automobile tail light.

http://rayvillard.com/science_papers.htm

[Bill Thompson]

Getting a signal from an intelligence society would be the most exciting thing I can imagine for humankind.

But I wonder this. As we continue to look and as we keep finding ourselves putting more energies into new ways to look, at what point do we decide to direct more energies in other things like, for instance, super telescopes and the launching of intergalatic AI probes?

Another thing to consider is this. At what point to we decide to dedicate our time and efforts inward towards things like finding a cure for cancer rather than looking for a signal from space?

[Guest_Richard Trigaux_*]

Another thing to consider is this. At what point to we decide to dedicate our time and efforts inward towards things like finding a cure for cancer rather than looking for a signal from space?

We could ask the same question about any other science/technology search: space station, fusion, robotics, particules physics, gravitationnal waves, etc. Why you would not go in one of the MER threads, and ask if it is not better to search for cancer than for those robots on Mars? So this concern is not relevant I think.