Seti@home pointless?

Almo said:
Not that I'm aware of... or radio astronomy wouldn't work very well.
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Then it is something else. Isn't this kind of communication highly directional and we could not pick up anything unless the communication was pointed directly at us?

But I still think I am right. As far as radio astronomy is concerned, this is a different kind of thing since we are talking about quality of signal not quantity of signal. Is RF signals reduced to noise after a few light years?
 
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Bill Thompson said:
Wasn't it determined that radio signals degrade after just a few light years?
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Bill Thompson said:
Then it is something else. Isn't this kind of communication highly directional and we could not pick up anything unless the communication was pointed directly at us?

But I still think I am right. As far as radio astronomy is concerned, this is a different kind of thing since we are talking about quality of signal not quantity of signal. Is RF signals reduced to noise after a few light years?
Click to expand...


If you ask the very same question enough times, in enough different ways, do you think the answer will be different?
 
If you really think that there is some simple fact about radio wave propagation that would make it impossible to detect after a few light-years of travel, why do you think there would be anyone interested in pursuing it? Granted that The Atheist (among others, of course) doesn't believe that it is worthy of spending any money on, his reasoning (nor the reasoning of any others that I know of) does not include any assumption that it is impossible due to problems in radio wave propagation. Of course, they could all (pro- and con- alike) be wrong, but if they are, then, as pointed out by Almo above, how does that reflect upon radio astronomy as a scientific pursuit?

No, it's not an argument. To fully understand this, look up electro-magnetic radiationWP propagation, properties of interstellar space for said radio propagationWP, and then you'll need to study some optimal receiver theory (http://adsabs.harvard.edu/abs/1979STIN...8018284L for example) in Electrical Engineering and Shannon's Information theoryWP.

Then it is something else. Isn't this kind of communication highly directional and we could not pick up anything unless the communication was pointed directly at us?
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No, directionality might make it work better, but almost all radio sources that radio astronomy studies are omnidirectional, and thus maximally weak, and they are still studied.

But I still think I am right. As far as radio astronomy is concerned, this is a different kind of thing since we are talking about quality of signal not quantity of signal. Is RF signals reduced to noise after a few light years?
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Nope, you're wrong. First, what do you mean by quality? Radio astronomers extract considerable information from the signals they receive (spectrum, polarization, all sorts of possible modulation techniques, etc, etc). Granted, they don't often look for, say, phase modulation because that isn't created by any known natural phenomena, but there is no known reason why such modulation should not be detectable over galactic distances if it was there. Radio is radio; if it is carrying information, it will not be the distance that matters but rather the cleverness of the SETI detection methods that may miss it.

Distance alone does not affect the signal-to-noise ratio of a radio signal, most particularly through a vacuum.

Finally, remember that radio is one form of EM radiation; others include light, infrared, ultraviolet. microwave, Xray and gamma rays. All propagate in exactly the same manner. In fact, a SETI civilization could use any one of them to signal us, as well as several other methods. The SETI people investigate radio mainly because it is not much affected by atmosphere.
 
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I think there is a point in the OP, though. Even with a radio telescope 100 times the sensitivity of Arecibo, we would not be able to detect our own broadband radio and TV leakage beyond our own solar system. Source.

SETI must be searching for a stronger, more directed (narrowband) signal.

BTW, best I can tell, none of this is about SETI@home in particular, right? It's just about SETI with radio telescopy in general. Nothing happens to degrade potential signals between the time they're received at Arecibo and the time they're divvied up and received by home participants, is there?
 
Bob Blaylock said:
If you ask the very same question enough times, in enough different ways, do you think the answer will be different?
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What? It was answered by people who have not thought it out and/or people who do not even know.

A response is not an answer. The response was not correct. The response was from people who are merely hopeful and not a scientist who knows this stuff.

Radio signals are a spectrum of light. Light is made of photons. While I have been looking on the web reading what others have said it has become clear that unless ET intentionally directs a powerful beam directly at us, we would not be able to distinguish a signal from them.

This is true for several reasons.

Here is one reason. Like I said, light is made of photon. As a signal goes out from its source traveling along the surface area of a sphere, how many photon are spread out along this surface area? (Surface Area of a Sphere = 4 pi r 2 ). Let me put this in perspective. People who like to believe that we have sent signals into space already that ET can hear and understand like to use 50 light years as an example and say that a star 50 light years away from us will have been picking up radio signals from us. Well, what they would have been listening to would be a degraded signal undistinguishable from the background radiation of space left over from the big bang because the photons from a 50 year old radio signal would be dispersed evenly on the surface area of a sphere the size of 31415.9 square light years. (Surface Area of a Sphere = 4 pi r 2 ) There is no way that an episode of "I Love Lucy" or the Olympics in Germany before World War II could be watched and enjoyed on a star system 50 light years away because the signal travels along a medium that would be too fragmented by the time it reached them.

Here is another reason. 50 light years is a long distance. Any radio signal traveling that distance would be subjected to the whatever is already in that area. I can think of several things that would influence the quality and integrity of a radio signal. The most influential would be the background radio noise left over from the Big Bang. a faint radio signal would merge with and be indistinguishable from such noise over time.

The Radio Telescope argument does not hold water. Radio Telescopes pick up signals from powerful objects like a star. Radio transmissions do not compare.
 
Bill Thompson said:
Radio signals are a spectrum of light. Light is made of photons. While I have been looking on the web reading what others have said it has become clear that unless ET intentionally directs a powerful beam directly at us, we would not be able to distinguish a signal from them.

This is true for several reasons.

Here is one reason. Like I said, light is made of photon. As a signal goes out from its source traveling along the surface area of a sphere, how many photon are spread out along this surface area? (Surface Area of a Sphere = 4 pi r 2 ). Let me put this in perspective. People who like to believe that we have sent signals into space already that ET can hear and understand like to use 50 light years as an example and say that a star 50 light years away from us will have been picking up radio signals from us. Well, what they would have been listening to would be a degraded signal undistinguishable from the background radiation of space left over from the big bang because the photons from a 50 year old radio signal would be dispersed evenly on the surface area of a sphere the size of 31415.9 square light years. (Surface Area of a Sphere = 4 pi r 2 ) There is no way that an episode of "I Love Lucy" or the Olympics in Germany before World War II could be watched and enjoyed on a star system 50 light years away because the signal travels along a medium that would be too fragmented by the time it reached them.

Here is another reason. 50 light years is a long distance. Any radio signal traveling that distance would be subjected to the whatever is already in that area. I can think of several things that would influence the quality and integrity of a radio signal. The most influential would be the background radio noise left over from the Big Bang. a faint radio signal would merge with and be indistinguishable from such noise over time.

The Radio Telescope argument does not hold water. Radio Telescopes pick up signals from powerful objects like a star. Radio transmissions do not compare.
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Yes this is correct. The only signal we are likely to 'read' would be a very tightly focused beam aimed directly at us from a very very powerful transmit ion source and then very unlikely to be further away that 100 ly
 
I watched a documentary on how fast the remains of human civilization would disappear if we all vanished in an instant, and one of the things they mentioned was that radio signals dissipate pretty fast. Of course, I don't know their sources, and TV documentaries have been going downhill lately.
 
Bill Thompson said:
What? It was answered by people who have not thought it out and/or people who do not even know.

A response is not an answer. The response was not correct. The response was from people who are merely hopeful and not a scientist who knows this stuff.

Radio signals are a spectrum of light. Light is made of photons. While I have been looking on the web reading what others have said it has become clear that unless ET intentionally directs a powerful beam directly at us, we would not be able to distinguish a signal from them.

This is true for several reasons.

Here is one reason. Like I said, light is made of photon. As a signal goes out from its source traveling along the surface area of a sphere, how many photon are spread out along this surface area? (Surface Area of a Sphere = 4 pi r 2 ). Let me put this in perspective. People who like to believe that we have sent signals into space already that ET can hear and understand like to use 50 light years as an example and say that a star 50 light years away from us will have been picking up radio signals from us. Well, what they would have been listening to would be a degraded signal undistinguishable from the background radiation of space left over from the big bang because the photons from a 50 year old radio signal would be dispersed evenly on the surface area of a sphere the size of 31415.9 square light years. (Surface Area of a Sphere = 4 pi r 2 ) There is no way that an episode of "I Love Lucy" or the Olympics in Germany before World War II could be watched and enjoyed on a star system 50 light years away because the signal travels along a medium that would be too fragmented by the time it reached them.

Here is another reason. 50 light years is a long distance. Any radio signal traveling that distance would be subjected to the whatever is already in that area. I can think of several things that would influence the quality and integrity of a radio signal. The most influential would be the background radio noise left over from the Big Bang. a faint radio signal would merge with and be indistinguishable from such noise over time.

The Radio Telescope argument does not hold water. Radio Telescopes pick up signals from powerful objects like a star. Radio transmissions do not compare.
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So your arguments are based solely on omnidirectional dispersement of the signal across a spherical surface, and the resulting signal-to-noise ratio. You say that radio astronomy arguments fail because they are looking at stars, not radio transmitters.

Suppose a directional signal is sent by an ET that has the directional brightness within a band of radio frequencies equivalent to that of a star. Is that impossible? Will it be impossible to our civilization within, say, another 5000 years of development (providing we don't get overwhelmed by the evangelists)?

Perhaps there is some limit on technology which we don't have an inkling about, and we'll hit a power ceiling in the next hundred years, so we may have only the 100 LY radius sphere mentioned by BonkingBear above. How many possibilities does that leave? Something in the rough area of 10000 stars, according to http://wiki.answers.com/Q/How_many_stars_within_50_light_years_from_earth. Is that enough to justify SETI? For a more complete justification, see http://www.bigear.org/vol1no1/kraus1.htm.
 
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10000 stars is probably not enough to justify SETI if it was tax payers money....but as its privately funded does it really matter. Personally I am pleased they are doing this work.....you just never know....we could be real lucky and there is another communicating intelligence somewhere on one of what may be some 50,000 planets. Even a negative result will tell us something.
 
If you consider that anyone out there intentionally beaming narrow band signals toward other stars would be at least as technologically advanced as we are and that we are currently developing systems to detect planets on which life is likely, then their similar technology would narrow down the range of planets to which the ET's must beam a signal. In other words, though we have tens or hundreds of thousands of stars to listen to, they might be able to narrow their broadcasts to mere hundreds (or fewer, assuming further advances in detection technology.)

I honestly don't expect SETI to find anything, but I can't say it's pointless. I really hope I'm wrong...
 
BonkingBear said:
Even a negative result will tell us something.
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Not much. Don't forget the transit time. If we don't get a signal when we point a telescope at a certain position, it only tells us that nobody sent a directed signal to us at the appropriate time in our past to be reaching us now.

Everything is so spread out in space and time, that even if there are a great number of technological civilizations in our galaxy, we may never know about them.
 
BonkingBear said:
Yes this is correct. The only signal we are likely to 'read' would be a very tightly focused beam aimed directly at us from a very very powerful transmit ion source and then very unlikely to be further away that 100 ly
Click to expand...

Then SETI @ Home is a huge waist of effort. No intelligence would ever pick us out of the billions to be important or worth any time or effort.

It is self evident. Our species was too stupid to know SETI @ Home was a waist of time.
 
Bill Thompson said:
Then SETI @ Home is a huge waist of effort. No intelligence would ever pick us out of the billions to be important or worth any time or effort.
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Nonsense! You're assuming that any intelligence making an effort being heard knows who it's sending to! That's woo territory.

The most "likely" scenario is that an alien intelligence would have detected Earth among other planets as a likely place for life (as we are currently trying to do with other starsystems). It would be plausible that efforts would be made to send radio signals Earths way.

Note to self: When insinuating stupidity in others at least make an effort to spell correctly...
 
JoeTheJuggler said:
Not much. Don't forget the transit time. If we don't get a signal when we point a telescope at a certain position, it only tells us that nobody sent a directed signal to us at the appropriate time in our past to be reaching us now.

Everything is so spread out in space and time, that even if there are a great number of technological civilizations in our galaxy, we may never know about them.
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I don't disagree - the problem is that despite all that we are discovering at the moment it only shows us how little we really know about the evolution of the galaxy and life in general.:)
 
I'm sort of in the SETI is futile, but not necessarily pointless, category. I'm leaning more to the terrestrial radio sources will be too dispersed to be detectable, side of the fence. But I would rather see money wasted on SETI that gives people some interesting hope and prospects for the future instead of governments wasting money on faith based initiatives or other BS policies that push us back in time.
It's like the first lunar landing. Mostly a pointless endeaver, but it excited the imagination and pushed the limits of what's possible.
 
A Bill Thompson thread on SETI!

This exact subject got him banned from the Bad Astronomy/Universe Today forum, just to warn you guys. He's that obstinate.
 
I do believe SETI@Home is pointless, but it has nothing to do with how valid SETI itself is as a project.
 
Checkmite said:
I do believe SETI@Home is pointless, but it has nothing to do with how valid SETI itself is as a project.
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I think this thread is mistitled. Based on the OP and what he's had to say since, his complaint or comment is about SETI using radio telescopy in general, and has nothing to do with the SETI@home project.
 
erlando said:
Nonsense! You're assuming that any intelligence making an effort being heard knows who it's sending to! That's woo territory.

The most "likely" scenario is that an alien intelligence would have detected Earth among other planets as a likely place for life (as we are currently trying to do with other starsystems). It would be plausible that efforts would be made to send radio signals Earths way.

Note to self: When insinuating stupidity in others at least make an effort to spell correctly...
Click to expand...

Would they? Do you think we could detect something like our solar system elsewhere? We have four huge giant outer planets each with some huge moons. If they could detect the four small inner planets, could they detect that one or two were in the so-called "sweet spot". I think the orbits of the outer planets would overrun the detectability of the inner planets or their placement and ETI would move on.

Of course there must be other reasons as well. As Fermi said, "where are they?".

I think SETI@Home is (or was) an exercise in self-admiration. The participants assumed that Earth and her inhabitants would be somehow naturally appealing to ETI and they would eagerly want to contact us. They miss the fact that the human species (by our own definition of mediocrity) is not an intelligent species. I am reminded of the fact that IBM had non-disclosure agreements in the early days of Microsoft that were so strict that IBM would not sign them. In other words, if another company presented IBM with such documentation to sign, they would refuse. Likewise, WE would not be interested in contacting a civilization as stupid as us. It is like the old adage, "I would not join a country club that would have me as a member". Just having a planet in the sweet spot (the proper distance away from the sun) would not be enough. ETI would first likely look for some other signs of worthy intelligence and, let's face it, we don't have it.
 
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Checkmite said:
I do believe SETI@Home is pointless, but it has nothing to do with how valid SETI itself is as a project.
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Yes. I have heard that they are thinking of moving on to lasers or light or something other than the SETI@Home project. I feel that the whole project was started to show off a possible technology using millions of home computers connected together on some joint project. And since now they have moved on to include other number crunching works, I think I am right.

JoeTheJuggler said:
I think this thread is mistitled. Based on the OP and what he's had to say since, his complaint or comment is about SETI using radio telescopy in general, and has nothing to do with the SETI@home project.
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They are connected or at least they were.
 
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Bill Thompson, I think you're still using "SETI@home" erroneously. The SETI@home project is merely a way of dividing up the data to be crunched so that it can be done on otherwise idle CPUs all over the world rather than at a central place.

It sounds like your beef is with SETI's emphasis on radio telescopy rather than something about the SETI@home project.
 
Bill Thompson said:
Of course there must be other reasons as well. As Fermi said, "where are they?".
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This argument depends on a number of assumptions, few of which are reasonable.

As you yourself pointed out, we wouldn't be able to detect our own presence even from the distance of the nearest stars without a narrowband beam sent long enough ago to reach us at the right moment, much less across galactic distances. Our civilization is nowhere near being able to leave ubiquitous evidence of our existence throughout the galaxy.

ETA: So by the same logic, one would conclude that we don't exist since such evidence of us (as self-replicating probes) isn't ubiquitous in the galaxy.

For a full refutation of the assumptions made in this argument, see this post.
 
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Safe-Keeper said:
I watched a documentary on how fast the remains of human civilization would disappear if we all vanished in an instant, and one of the things they mentioned was that radio signals dissipate pretty fast. Of course, I don't know their sources, and TV documentaries have been going downhill lately.
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AH-HA!! That was where I heard that information! Thanks for jarring my memory.
 
Bill Thompson said:
They are connected or at least they were.
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But you have no beef with the distributed grid computing approach to data analysis (which is what SETI@home is). Your beef is with SETI.

SETI@home could be discontinued, and the complaint you have about SETI would still exist. To clarify, surely you're not talking about signals degrading somewhere between Arecibo (and wherever they go to be divided into work packets) and my home computer, are you?
 
My position is that SETI is completely useless, but that doesn't mean that they need to stop. I allow other people to do stupid useless stuff all the time.


The only way that a SETI effort could be useful is if we invented a form of FTL communications and thus can possibly overhear alien communications.
 
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!"
Radio Astronomy, John D. Kraus, 2nd edition, Cygnus-Quasar
Books, 1986, P.O. Box 85, Powell, Ohio, 43065.

Radio Astronomy, J. L. Steinberg, J. Lequeux, McGraw-Hill
Electronic Science Series, McGraw-Hill Book Company, Inc,
1963.

Project Cyclops, ISBN 0-9650707-0-0, Reprinted 1996, by the
SETI League and SETI Institute.

Extraterrestrial Civilizations, Problems of Interstellar
Communication, S. A. Kaplan, editor, 1971, NASA TT F-631
(TT 70-50081), page 88.
​
Also, there are reasons why ETI would NOT target us with a direct
transmission. Our solar system was formed from the debris of an
exploded star that was much bigger than our sun. The complex and
heavy materials necessary to produce life as well as a protective
magnetic field like our Earth has was because of the denser material
from the star that our solar system came from. Our star system is not
in the middle of the GHZ. So we are both our of the range where ETI
would expect to see life and we are orbiting a non-impressive star.

About the GHZ:
http://www.thelivingcosmos.com/ExtrasolarPlanetsandLife/HabitablePlanets_12May06.html

And, by the way, it seems to me that as science and knowledge progress, these habital zones are shrinking (not expanding like we hope). If you can get your hands on this article, it is very good. It shows that there is not as much hope as finding ETI as we think:

http://www.sciamdigital.com/index.c...LEID_CHAR=C94598AF-2B35-221B-674229153009236A
Refuges for Life in a Hostile Universe; by Guillermo Gonzalez, Donald Brownlee and Peter D. Ward; 8 Page(s)

So there are lots of factors that add up to them not signaling us directly.
#1) We are not in an ideal place in the galaxy. #2) Our star is a small and
less than ideal sun. #3) There may not be as many ETI's as we would like
to believe.
 
Bill Thompson said:
http://www.faqs.org/faqs/astronomy/faq/part6/section-12.html
Click to expand...
Note that I linked to this very page in Post #7 of this thread.

Do you get that the thread is mistitled yet? None of this has to do with SETI@home, does it?

Your complaint against SETI is that it is extremely unlikely to detect anything other than a narrow beam signal sent to us at an appropriate time in the past to be "audible" just exactly when we "listen" to that spot in our sky. That's a legitimate complaint, but it has nothing to do with the distributed processing project that is SETI@home.

My reply to your actual complaint is that it costs very little to do this sort of thing. Arecibo is not being re-directed from other work. Instead, SETI is just piggybacked onto whatever other research the telescope is doing. As someone else mentioned, the expenses are paid by private money, so I have no problem with it at all. (And, there is a vanishingly small but non-zero chance that they just might hit the lottery and find the needle in the cosmic haystack, if I might mix metaphors!)
 
Wowbagger said:
I think what Bill Thompson is referring to is the Inverse Square Law. But, it doesn't apply to focused beams, and makes little difference when radio signals eminate from around the entire body of the object.
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Focused beams have their own problem. If you take a laser pointer and shine it towards the moon by the time it hits the moon your beam is ten kilometers wide all because you focused it.
 
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Bill Thompson said:
http://www.faqs.org/faqs/astronomy/faq/part6/section-12.html


So there are lots of factors that add up to them not signaling us directly.
#1) We are not in an ideal place in the galaxy. #2) Our star is a small and
less than ideal sun. #3) There may not be as many ETI's as we would like
to believe.
Click to expand...

That's wrong! 1) We are in a good place within our galaxy - a very stable region

2) Our Sun is an average size with sufficient stability to give life time to develop - at least 5 billion years - bigger stars ldo not live longer enough for life (as we know it to develop)

3) Hmm...how many do we like to believe ?
 
Bill Thompson said:
So there are lots of factors that add up to them not signaling us directly.
#1) We are not in an ideal place in the galaxy. #2) Our star is a small and
less than ideal sun. #3) There may not be as many ETI's as we would like
to believe.
Click to expand...

What strange ideas! It sounds like you're making a case for the Rare Earth Theory but using the exact opposite arguments they use. They say everything about the Earth is required for an intelligent civilization--that the Earth is in the optimum spot in the galaxy and that the Earth is exceptionally massive, more massive than 95% of stars.

At any rate, you left out the one valid reason for why we're not likely to get a signal from an ETI: everything is spread apart by unimaginably vast stretches of space and time.
 
JoeTheJuggler said:
What strange ideas! It sounds like you're making a case for the Rare Earth Theory but using the exact opposite arguments they use. They say everything about the Earth is required for an intelligent civilization--that the Earth is in the optimum spot in the galaxy and that the Earth is exceptionally massive, more massive than 95% of stars.

At any rate, you left out the one valid reason for why we're not likely to get a signal from an ETI: everything is spread apart by unimaginably vast stretches of space and time.
Click to expand...

Which is why other galaxies should be omitted when talking about this stuff as well.

I wish I could put Refuges for Life in a Hostile Universe online but there are probably copyright issues. If anyone disagrees with me, I would like to point them to this Scientific American article.

I knew Earth was the most dense planet in the solar system but I did not know that its density was also unique among stars (are you SURE about this? Can you tell me your sources?). The more I hear and learn the more I think we are rare and getting signals from space will be improbable.

Update: Arazona.edu has posted the the article here: http://atropos.as.arizona.edu/aiz/teaching/a204/etlife/SciAm01.pdf
 
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Bill Thompson said:
Which is why other galaxies should be omitted when talking about this stuff as well.
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Nowhere did I mention other galaxies.

Are you denying that there are vast stretches of space and time to consider even within our galaxy?

Do you know what percentage of the volume of our galaxy we have explored in any meaningful way?
 
Jebus Cristo on a cracker... Not again...

I will say that I view SETI@Home as a longshot, but since it's all privately funded, SETI@Home (and SETI) are worth it on the off chance that something is sent here. In our history, whe have only sent FIVE signals worth anything in relation to communicating outside our solar system http://en.wikipedia.org/wiki/Active_SETI And even then I'm not sure how impressive those signals really are.

As I contend over and over again; we humans seem to lack a great deal of imagination when it comes to even considering how and under what conditions any alien type of life could start. Furthermore, we seem to be incredibly human/earth centric in all our thinking. I am betting that evolution will surprise us a great deal (and even freak a lot of us out!).
 
AWPrime said:
My position is that SETI is completely useless, but that doesn't mean that they need to stop. I allow other people to do stupid useless stuff all the time.


The only way that a SETI effort could be useful is if we invented a form of FTL communications and thus can possibly overhear alien communications.
Click to expand...

Come on now. It makes for a great screen saver. One that helps sort through all the signals which ultimately helps them toward their goals.

I am curious to know how the search for life in the galaxy could be stupid or useless.

To me it seems to be the utmost of importance, regardless of the apparent futility of the efforts being conducted. Imagine what changes a truly positive result would create.
 
thesyntaxera said:
Come on now. It makes for a great screen saver. One that helps sort through all the signals which ultimately helps them toward their goals.

I am curious to know how the search for life in the galaxy could be stupid or useless.
Click to expand...
I don't think that they even have a chance. Its their method that is retarded not the goal.
 
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