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Beery
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Message 865742 - Posted: 15 Feb 2009, 13:53:03 UTC

There are a bunch of PC's crunching numbers. To date, has there been any interesting data that has been reported?

I look at the graphs from time to time and wonder what kind of data will cause someone to go Hmmmmmmm.


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Message 866024 - Posted: 16 Feb 2009, 5:43:22 UTC
Last modified: 16 Feb 2009, 5:43:49 UTC

Billions of detections and hundreds of millions of work units have been processed.
http://setiathome.berkeley.edu/sci_status.html

A few years back, the SETI team combed through these detections and only ONE (yes just ONE) merited a second look. Sadly in the end it turned out not to be a signal from ET and wasn't even interesting enough to be worthy of investigation by other SETI scientists.
http://en.wikipedia.org/wiki/Radio_source_SHGb02%2B14a

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Message 866365 - Posted: 17 Feb 2009, 3:01:46 UTC

The number of wu's processed is not particularly interesting or an achievement.

A better question might be: After 567,064,792 wu's having been processed, how much more confident are we that there is no other technological civilizations in the universe.

Or: How many wu's must yet be processed to make the claim there is no life out there at the 1% significance level?

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Message 866496 - Posted: 17 Feb 2009, 14:59:22 UTC - in response to Message 866365.
Last modified: 17 Feb 2009, 15:11:05 UTC

The number of wu's processed is not particularly interesting or an achievement.


Definitely have to disagree with that. SETI@Home represents the incredible potential of distributed computing. The raw processing power of SETI@Home's distributed computing network is the equivalent of or better than the world's most powerful super computers.

A better question might be: After 567,064,792 wu's having been processed, how much more confident are we that there is no other technological civilizations in the universe. Or: How many wu's must yet be processed to make the claim there is no life out there at the 1% significance level?


I see you have a lot of accumulated credit with SETI@Home but I think you misunderstand the aim of SETI.
It's obviously beyond the scope of any SETI research or indeed any real science experiment humans are currently capable of to determine with any degree of confidence that there are no other technological civilization in the universe let alone our galaxy.

Science is not really about proving that something *doesn't* exist.

No practical amount of processed WUs can bring us any closer to be able to make the claim that "there is no life out there".

However, what the continued processing efforts of SETI@Home and the SETI research at the Allen Telescope Array can help us answer is...
Are there any civilizations within our galactic neighborhood actively transmitting an electromagnetic signal to Earth within the band of radio frequencies in which we are currently monitoring?

That is not the same question as Is there life out there? or Are there other technological civilizations in the universe?

See other threads on this forum for speculations on communication mediums aliens might use besides radio and potential solutions for the Fermi paradox in which aliens would not actively transmit to Earth.

As far as what science can tell us about alien life, NASA's Kepler mission will soon be able to tell us how common Earth-size terrestrial worlds are in our galaxy, the James Webb Space Telescope could potentially be able to indirectly detect the presence of life on worlds that Kepler finds; these results would allow us to make better informed assumptions about how common life is in our galaxy.

As far as radio communication from other civilizations, Seth Shostak believes that if fairly generous solutions to the Drake equation are correct, then SETI should successfully detect an alien signal within another 20 years. That's accounting for the continued processing of SETI@home AND the work at the Allen Telescope Array....AND it's assuming that alien civilizations are common. And he estimates it would STILL take another 20 years! Half a billion WUs isn't even scratching the surface of our neighborhood let alone the galaxy or the universe. Of course, we could get lucky tomorrow.

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Message 866517 - Posted: 17 Feb 2009, 15:54:08 UTC - in response to Message 866496.

The number of wu's processed is not particularly interesting or an achievement.


Definitely have to disagree with that. SETI@Home represents the incredible potential of distributed computing. The raw processing power of SETI@Home's distributed computing network is the equivalent of or better than the world's most powerful super computers.



With all due respect, your's is a position I rail against in my starker moods.
* First, Seti Classic and then BOINC demonstrated years ago the engineering feasibility of large scale distributed computing (DC) organized using a public volunteer model. The Stanford Folding project is another example. There are other, non-BOINC models as well. If DC a la BOINC is the acheivement desired, then it has been achieved. Done. Fine. Let's stop wasting time proving it over and over every day. Doing so is a waste of human and computer time, and of energy.
* Any project could have been used to prove the model, not just Seti. If your position is that the scientific objectives of the individual projects are not important, honing the stone (BOINC) with revision after revision that is occuring today is also a waste in the sense that no significant new concepts are being introduced. Incremental improvements are being made, of course, but to what end? I say that the project is important and the results of the project should be our aim.
* Therefore, it is fair to ask what Seti has accomplished, what results have been attained. Looking at other projects, one should ask the same question. I am not familiar with many others, but I have kept loose contact with einstein. Einstein seems to have a structure designed to document achievement. Their data reduction is organized into what must be logical blocks, which then is distributed to the DC volunteers. When the data is returned, it is analyzed and papers are published in professional journals. It appears that seti is not yet that mature, for whatever reason. (BBC interviews and similar PR communications are glitzy, fun and probably necessary, but are not acheivements per se.)

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Message 866527 - Posted: 17 Feb 2009, 16:55:09 UTC - in response to Message 866496.


A better question might be: After 567,064,792 wu's having been processed, how much more confident are we that there is no other technological civilizations in the universe. Or: How many wu's must yet be processed to make the claim there is no life out there at the 1% significance level?


I see you have a lot of accumulated credit with SETI@Home but I think you misunderstand the aim of SETI.
It's obviously beyond the scope of any SETI research or indeed any real science experiment humans are currently capable of to determine with any degree of confidence that there are no other technological civilization in the universe let alone our galaxy.

Science is not really about proving that something *doesn't* exist.

No practical amount of processed WUs can bring us any closer to be able to make the claim that "there is no life out there".

However, what the continued processing efforts of SETI@Home and the SETI research at the Allen Telescope Array can help us answer is...
Are there any civilizations within our galactic neighborhood actively transmitting an electromagnetic signal to Earth within the band of radio frequencies in which we are currently monitoring?

That is not the same question as Is there life out there? or Are there other technological civilizations in the universe?

See other threads on this forum for speculations on communication mediums aliens might use besides radio and potential solutions for the Fermi paradox in which aliens would not actively transmit to Earth.

As far as what science can tell us about alien life, NASA's Kepler mission will soon be able to tell us how common Earth-size terrestrial worlds are in our galaxy, the James Webb Space Telescope could potentially be able to indirectly detect the presence of life on worlds that Kepler finds; these results would allow us to make better informed assumptions about how common life is in our galaxy.

As far as radio communication from other civilizations, Seth Shostak believes that if fairly generous solutions to the Drake equation are correct, then SETI should successfully detect an alien signal within another 20 years. That's accounting for the continued processing of SETI@home AND the work at the Allen Telescope Array....AND it's assuming that alien civilizations are common. And he estimates it would STILL take another 20 years! Half a billion WUs isn't even scratching the surface of our neighborhood let alone the galaxy or the universe. Of course, we could get lucky tomorrow.


I don't agree with your various claims, at least as you express them. But it may be useful to explain my thinking here instead.

The scientific method can be succinctly described as follows: 1) make a hypothesis, and 2) try like hell to prove it is incorrect. If 2) is successful, then 3) make a new hypothesis and repeat. For the philosophically minded, 'truth' is at the end of an infinite sequence of such steps.

I suggest that each of us have implicitly embraced the null hypothesis that "there is no ET" when we started computing for seti. And each of us are now processing data like crazy trying to find evidence of a signal which would disprove the hypothesis.

A proper hypothesis in a case like seti would involve some sort of model, and any model should be able to predict something. In fact, in most of science, the predictions made by a given model of the hypothesis are the statements being tested in step 2 above.

Now getting to my point, if we claim there is no ET it is fair to ask how certain we are of this claim. Here is where a framework is needed in the model. If I were in this business professionally, I would think that one should create a mathematical model of the space-time distribution of potentially life supporting planets. Then I would segment the observable universe into elemental volume elements. As seti analyzes each of these volume elements (actually rays of elements because time cannot be specified) we could eliminate that section of space-time. So for a given angular granularity(*), we could indeed quote how confident we are of no ET at some statistical significance level by counting the segments that we have processed and comparing to the model's predictions.

In seti's case, you mention the Drake equation. The Drake equation could be a start of such a model, although it seems like a back of the envelope conjecture.

By the way, a different null hypothesis could be made, namely "there is life out there". This is a popular choice by most lay people it seems (and the crystal worshippers amongst us). In this case, it is difficult to state (mathematically/statistically/objectively) how confident we are of this claim using the seti experiment.

(*)I should also add that real life experimental limitations also come into play and limit our confidence (S/N, incomplete sky coverage, etc.). They would have to be folded into the confidence estimate as well.

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Message 866721 - Posted: 18 Feb 2009, 11:43:13 UTC - in response to Message 866527.

We can be as scientific and as analytical about the issue of non-detection until the cows come home.
We have proven distributed computing works.

The bottom line for detection is this,
it's all down to the luck of randomness.
namely if we are lucky enough to have an advanced civilisation transmitting within RANGE of us.

Advanced life IS out there, but may be scattered far and wide.
The results will come in time when we can look deeper around the galaxy,
as technology improves.

This is a cash poor project and we must be patient.

Personally, I'm even more determined now to run the client than I was when the project started, and while I can, I will.

Keep crunching.
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Message 866741 - Posted: 18 Feb 2009, 13:54:43 UTC - in response to Message 866721.

Agreed; volunteer DC works. This part of the project is done. So why go on?

"Advanced life IS out there": How sure are you of this? Can you be quantitative?

<Soapbox>
Our societies are in trouble. There is too much PR, posturing, pandering, contradiction, hypocracy, greed, corruption, lack of integrity or principles, ... Can anyone explain why we pay entertainers like Steven Spielbeg, Michael Jordan or Madonna so much money when their typical audence member makes so (relatively) little? .... And so on.

The successful resolution of this paradox or our fate is improved education, albeit not the type that is provided in US public schools, I'm afraid. We need to learn to think like scientists, to objectively scrutinize everything, and learn to think analytically.

So I don't believe "its all down to the luck of randomness". A smart search methodology, with open, objective analysis and critical thinking is far more likely to succeed than just blindly churning out wu's, which is a sort of dart game for losers. It would be good if the seti project could work towards a more visible scientific methodology.

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Message 866773 - Posted: 18 Feb 2009, 17:15:06 UTC - in response to Message 866741.

Agreed; volunteer DC works. This part of the project is done. So why go on?

"Advanced life IS out there": How sure are you of this? Can you be quantitative?

<Soapbox>
Our societies are in trouble. There is too much PR, posturing, pandering, contradiction, hypocracy, greed, corruption, lack of integrity or principles, ... Can anyone explain why we pay entertainers like Steven Spielbeg, Michael Jordan or Madonna so much money when their typical audence member makes so (relatively) little? .... And so on.

The successful resolution of this paradox or our fate is improved education, albeit not the type that is provided in US public schools, I'm afraid. We need to learn to think like scientists, to objectively scrutinize everything, and learn to think analytically.

So I don't believe "its all down to the luck of randomness". A smart search methodology, with open, objective analysis and critical thinking is far more likely to succeed than just blindly churning out wu's, which is a sort of dart game for losers. It would be good if the seti project could work towards a more visible scientific methodology.

</Soapbox>

Unfortunately SETI@home piggybacks on others research. When the telescope is moved seti sees something different. that and they are now using the MultiBeam receiver to cover more area of the sky. I assume that most Use on Arecibo is not for looking at local stars but much more distant interstellar radio sources. THat being said Yes Berkeley should be looking at much more distinct local starts that are more likely to be sources of intelligent signals. However this costs a great deal more money than they or we have.
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Message 866793 - Posted: 18 Feb 2009, 18:24:01 UTC - in response to Message 866773.

I understand the piggyback concept. One can handle this a number of ways, but simply put, the 'observable' universe is limited, at least, by the speed of light and where the telescope has been. Given this limitation, a framework can still be put into place to answer statistically questions like "how confident are we?". The professional scientists involved should be working toward this kind of description, it seems to me.

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Message 866840 - Posted: 18 Feb 2009, 20:34:28 UTC - in response to Message 866527.
Last modified: 18 Feb 2009, 21:30:05 UTC

we could indeed quote how confident we are of no ET at some statistical significance level by counting the segments that we have processed and comparing to the model's predictions.

a framework can still be put into place to answer statistically questions like "how confident are we?"


I'm truly astonished that you keep making this claim. Trust me, you're barking up the wrong tree.

SETI efforts around the world are currently focused on listening to a specific part of the electromagnetic spectrum for a signal generated in that part of the spectrum by an alien civilization.

Most SETI endeavors do not have the technological capability to search very much of this part of the spectrum; instead, they may choose to focus on just a narrow band within this part of the spectrum. This is the approach that the SETI@Home team has chosen despite the apparently impressive processing power of the SETI@Home project.

SETI@Home ONLY listens for a signal being transmitted within a band of radio frequencies known as the Water Hole; they choose to listen here because they make the assumption that aliens would transmit a signal to Earth within this range of frequencies since it is particularly quiet as far as natural cosmic background noise and it is between the range of frequencies caused by the excitation of hydrogen and hydroxyl which make up water. Since all life on our planet depends on water for survival, SETI@Home also assumes that this is the case for ET.

To summarize, here are the assumptions that SETI@Home is making:
a) An alien civilization will use radio waves for interstellar communication.
b) They will be water-based or they will know that we are.
c) They will transmit radio signals in the narrow band between the hydrogen and hydroxyl lines.

Furthermore, EVEN IF all of those assumptions are correct, then in order to successfully detect this signal, a few additional things must ALL be true SIMULTANEOUSLY;
a) It would almost certainly have to be specifically targeted toward Earth
b) We would have to be listening for it at the exact time at which it passes over the Earth
c) We would have to be listening for it in the exact direction from which it is transmitted

Other SETI teams disagree with SETI@Home's assumption about the radio Water Hole. Instead, they choose a more thorough approach in which they listen to a much broader range of frequencies. However, unlike SETI@Home, they meticulously target individual stars one by one due to their assumption that some stars are more likely to harbor life than others.

This is the approach taken by the SETI Institute, founded by Frank Drake, which is the organization most people think of when they think "SETI" but which is NOT affiliated with SETI@Home.

The SETI Institute is currently using an incomplete array of radio telescopes for their targeted search which by some accounts hasn't even actually begun in earnest. In the decades in which the SETI Institute has carried out their "listening", members of the institute have pegged the total number of stars they have listened to at around 1,000. Obviously this is an insignificant amount next to the total number of stars in our galaxy.

Obviously, almost all of the assumptions SETI researchers base their work on could be definitively FALSE and our galaxy could still be teeming with technological civilizations.

Indeed, it's fairly easy to imagine that this might be the case. Many of us have openly expressed our doubts about SETI's assumptions, particularly the use of radio waves as a medium for interstellar communication. It's also easy to imagine that alien civilizations may have no interest whatsoever in contacting Earth, or that if they do, they would do so using some other method that is currently difficult or impossible for us to detect.

And of course if our galaxy is brimming with microbes or animal organisms (obviously this counts as "life out there"), a complete failure to detect radio signals from any of the hundreds of billions of stars would not tell us anything about their existence.

each of us have implicitly embraced the null hypothesis that "there is no ET"


Again, the reason your "null hypothesis" idea is wrong is because there is NO reliable method currently available to mankind to conclusively test that hypothesis.

Perhaps you could rephrase your null hypothesis; "there is no ET that is using radio waves to transmit a signal which is currently passing over the Earth and is within a range of frequencies we are scanning".

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Message 866917 - Posted: 18 Feb 2009, 23:51:00 UTC - in response to Message 866840.

Taurus, you are being too literal. It is short-hand to say 'ET'.

I don't disagree at all with the various caveats you have listed. These qualifiers are part of the model being tested. Various seti groups may have different qualifiers, justified or not. I did not intend to discuss these nuances here, but accept that they exist and their selection is not unique.

Instead, my point is that our computing project aspires to find ET (within our model specifications and limitations). To measure our progress we should trend how much of the observable space-time we have examined. Such a metric is in fact a measure of how confident we are that ET does not exist (within our model). Furthermore, the project should be organized so that we focus on this confidence metric, not on the number of wu's we have processed. The latter is a childish mis-direct if you ask me.

So when someone asks for results, which was the point of this thread, we should hope to say that we are only X% sure that ET does not exist (within our model), rather than that we have computed 500,000,000 wu's.

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Message 866931 - Posted: 19 Feb 2009, 0:16:23 UTC
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I'm reasonably certain that the SETI Institute is currently doing area, rather than targeted searches with the Allen Telescope Array, and, at times, instrument calibration. When I checked a few minutes ago they were set in a fixed alt/azimuth position. In this configuration, the rotation of the Earth will cause swaths of the sky to be swept out, which contain many stars. One often sees whole galaxies given as the intended target, such as 3C274 (the relatively nearby Virgo A 'radio galaxy), this morning, or substantial sections of galaxies. I observed the records of the the SETI Institute's Phoenix Project when they were conducting targeted searches at Arecibo. Individual star designations were consistently given. Michael

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Message 866934 - Posted: 19 Feb 2009, 0:21:16 UTC

SETI @ Home as it currently works cannot prove that there are no other technological civilizations in the galaxy.

1) The Aricebo telescope only covers a band around the equator, and does not reach the poles at all.

2) The sensitivity of the receiver is enough that it could detect us at about a range of 50 Light Years.
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Message 866949 - Posted: 19 Feb 2009, 0:58:24 UTC - in response to Message 866934.

I think we understand this, John. We can only see/detect what we can see/detect. Within that constraint, then, we can only increase the confidence there is no ET by continuing our work, reducing wu after wu. Proof that ET does not (did not?) exist is not possible, of course.

However, I'm not firm on how the 50 l-y limit comes about, although I've heard reference to it before. Perhaps a good link here explaining the physics might be interesting to others; it would for me. I'm assuming it is more than a S/N and 3K background argument.

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Message 866958 - Posted: 19 Feb 2009, 1:21:29 UTC

I don't understand the utility of determining how far away Arecibo could detect a civilization with our own technical limitations. Given the very short history of our technical civilization, it seems far more likely that extraterrestrial civilizations are vastly more advanced than we are. Michael

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Message 866978 - Posted: 19 Feb 2009, 2:52:34 UTC - in response to Message 866958.

I don't see the connection between your two sentences, Michael.

We probably need to know our limitations because (skipping over the numerous details) they translate into a maximum distance a signal source of some fixed magnitude might be positioned (at some time in the past) for us to detect it. A signal arrives at Earth from a distance and travels at the speed of light. We don't know when the signal was emitted, so we don't know how far away it came from, e.g. x = c t; earlier signals come from farther away. So the question is not of 'utility' as much as it is of knowing how to interpret the data in the context of other data, like the star and galactic atlases. I'll admit, this is pretty loosy-goosey, but I hope it helps.

The claim that we have a short history and others have a longer one is not obviously true. How do we know we have a short history? What do you compare to? How do we know others civilizations haven't evolved more rapidly or less rapidly? How do we know they all started at the same time? How do we know they exist?

If you use the life of radio on Earth, say 200 years, as the time scale, then we might be receiving radio signals from some planet within 200 light years of us right now. (I think I have one stuck in my cache as I type!) However, older civilizations far away might have produced signals for us eons ago that are just now getting here due to the distances involved. This is where our detection limitations come into play to help our interpretation of any recognized signal, once found.

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Message 867012 - Posted: 19 Feb 2009, 4:54:09 UTC - in response to Message 866978.

If we consider that technical civilizations may well have already persisted for millions, if not billions of years, then our just over one century of radio capability is very short indeed by comparison. The statistical chances of any one of them just happening to be in this same first hundred years of technical capability, or anywhere near it, are remote. Might we hear very old transmissions from very far off civilizations, which were, at the time of transmission, at about our technical level? this is not out of the question, but such transmissions would be very weak, in comparison to those of more advanced civilizations, and so much less likely to be detected by our current efforts. In practical terms we are far likelier, it seems, to hear from what would be, by our standards, super civilizations than ones like our own. This, of course assumes that no selection factors are present, such as the disinclination of advanced civilizations to contact backward ones. But we really can't know, at this juncture, if such factors exist or not. Michael

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Message 867063 - Posted: 19 Feb 2009, 13:54:42 UTC - in response to Message 867012.

I agree with you that if there are other civilizations, then there are many; that their technological sophistication will have a distribution; and that we will not 'hear' from the low-tech end of the distribution. It also seems likely to me that we will not 'hear' from the high end, either, unless they are actively looking for us because random emission of copious energy to space would be frowned upon by advanced cultures; look to our own recent transition from broadcast to cable and fiber as our primary communication technology.

There is of course no evidence that some civilizations have "persisted for millions, if not billions of years", nor does that claim seem likely. Instead, it seems that Earth's history seems to be very uneventful. It has evolved with a fairly average star and has existed for about 5B years, which is a considerable fraction of the age of the universe. There is also no evidence I'm aware of that our evolution has been slowed or accelerated by unusual events. So if we hear from a typical civilization, we will hear from beings similar to ourselves, albeit referenced at some time in the recent past, which brings me to the next point.

Given that we cannot expect to hear from ET if he is too far away because the signals would not be here yet, nor will they be strong enough, I suspect that our most likely hit will be close to us. How close? It sounds like 100 l-y is some sort of reasonable estimate of our current abilities, from John's statement below. That means that the detectable ET's will be similar to ours technologically. The Milky Way is about 100K l-y in size so the signals are likely to be intra-galactic.

Obviously, I too am speculating. Having said that, I want to re-iterate that the point of this thread was 'where are the results'. To that question, I think we should have a better standard more aligned with the quest, than what we have today. I also think that counting the wu's is not a measure of our progress and it is shortsighted to think so. So I hope the project astro-scientists would pause for a moment and address this omission, if only crudely for now.

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Message 867069 - Posted: 19 Feb 2009, 15:23:45 UTC - in response to Message 867063.

The galaxy certainly appears to be old enough that a great many life-favorable stars have existed for billions of years longer than our Sun. We have no basis for supposing that life couldn't or didn't originate and evolve in these star systems, billions of years before life on Earth. A civilization at the far end of the galaxy need only have evolved as far as our basic technical level, and as late as about 100,000 years ago to have covered the entire galaxy with its radio signals. Their being older and more technically advanced than that should only improve our odds of detecting them. Michael

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