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Nice response, Johnson:

Seti does not broadcast. We are only listening, so it isn't about sending signals to aliens and hoping they can understand us, but instead listening to the cosmos for signs of artificial broadcasts.

yes. that's correct. Did you see Geo's link that gives a brief explanation of what SETI is searching for?
Look at if you haven't already. It's a great little article.

As outlined by Sagan himself, one of the possible dead-ringers for an un-natural signal source would be a progression of beats that produce prime numbers. Using the reasoning that if we humans decided we wanted to make ourselve obvious to another society searching the skies for signs of us, we would use a simple pattern that could only have been generated by intelligent entities. That's not saying that that specifically is what SETI is looking for, but things along those lines.

First of all, Sagan himself is not an expert on alien intelligence, advanced alien civilizations, alien language, or alien communication transmissions/ and or methods. A progression of prime number beats would possibly be a "dead-ringer" for an attempt at communication by a HUMAN, not an alien. That is a projection fallacy:
- we are intelligent. we would attempt communication this way. we would signal this way, therefore, this is what we should be looking for and if we find it, it's "intelligence"

Falsification. If there ever was a signal like this detected, the people dog-piling ways to falsify would be lined up around the block. Not being an astronomer myself, what i would do is sit on that signal and look for the signal to change to something that can be explained through natural means. Then comes the big question that if we've actually discovered an alien signal, would we want to broadcast back to them to reveal ourselves in like signals?

I think you're right with the above comment. And that's how I as a layman imagine how things would unfold.
However, what I understood from the link Geo provided, SETI isn't actually looking for patterns.
Here is a quote from Geo's link: (emphasis mine)

"SETI scientists do not look for patterns but rather a lack of patterns in a signal. Although this may seem puzzling, it¿s really a matter of physics. The first challenge facing any SETI project is detecting a signal against the background of cosmic and terrestrial noise. A signal containing a great deal of information will be spread across the spectrum more than a very simple signal containing little information would be. An "informative" signal will look more like random noise and thus will be harder to detect. So, in SETI, we look for very simple signals"

My question is how would the detection of a lack of patterns that's interpreted as an intelligent communication be falsified if we don't have anything to compare it to that's alien? How would the scientific method be applied here?

Trying every possible formulation of natural phenomena to duplicate a pattern like the primes would of course come first on the list. IS there any combination of pulsars and black holes that could make that signal? If anything else at all could be responsible, that will be probably taken as the most likely scenario, especially if the signal does not repeat itself.

We know its natural phenomena that's up there in the sky.
What we don't know is a) how much is out there and, b) how much of it is noise we've never heard, is capable of masking an intelligent signal, or c) if something that doesn't appear to be a binary intelligent signal IS in fact an intelligent signal.
What's the criteria that's distinguishing all this?
And how many patterns of primes are we talking about?

When do we abandon the search? When it is no longer economically feasible. When a better more cost effective method is created to scan the skies for signals. Given the size of the visible universe and the miniscule amount of sky that SETI can cover it would take forever to really look at enough sky to say we've ruled out any territory. SETI trains itself to look at a pinprick of the night sky for however many hours and then moves on. The very second they turn away from that star they could be getting bombarded by alien S.O.S. signals and we wouldn't know. SETI is even worse than scooping a spoonful of water out of the ocean and concluding that there were no whales. You could never rule out any star based on having just listened to it last month.

It's abandoned when nobody wants to privately fund it any more. It's already been abandoned by public funding.
So anyone willing to donate is free to do so. I don't see anything wrong with that and hope it continues.
But the question is, if this was public funded science, how long would we fund it just because we are told it's a valid scientific experiment - despite zero progress and zero evidence for over 20 years?
Science isn't practiced in a vacuum.

It really is a tremendous crap-shoot with no gaurantee of success. Does it need to go on? I think it's worth while. But i also think the odds are incredibly stacked against it.

Right. Then it ceases to become a working hypothesis.
Is a hypothesis that produces nothing after 20 years still a scientific hypothesis?
Maybe in your heart it still is. In the scientific community, it dies.

Hypothesis. There may be intelligent species who have learned to modulate RF frequencies and transmit them for their own purposes.

It is known that such signals as generated in our own experience can be intercepted and interpretted to be evidence of our own existence. And even if such signals can not be decoded to read the specific message, they can be shown to carry coded content, distinct from natually occuring sources of radiation.

Experiment. Listen to stars and look for signals not consistent with naturally occuring "noise".

be shown to carry coded content??
therefore what? It's got to be intelligent??

really now..
we aren't saying that about DNA, are we?

ant wrote:A progression of prime number beats would possibly be a "dead-ringer" for an attempt at communication by a HUMAN, not an alien. That is a projection fallacy:

You completely overlook what he's saying. He is not saying that all aliens will inevitably send a progression of prime numbers.

If we received a signal that included a progression of prime numbers, over and over and over, and the scientists ruled out any alternative hypothesis that we could think of, the only conclusion left is that the signal was sent by intelligent life.

ant wrote:It's abandoned when nobody wants to privately fund it any more. It's already been abandoned by public funding.
So anyone willing to donate is free to do so. I don't see anything wrong with that and hope it continues.

I agree.

Would you donate if you were a billionaire? I probably would, but I'm not sure. I'm not much of a gambler.

You completely overlook what he's saying. He is not saying that all aliens will inevitably send a progression of prime numbers.

Just some aliens?
Which aliens?

If we received a signal that included a progression of prime numbers, over and over and over, and the scientists ruled out any alternative hypothesis that we could think of, the only conclusion left is that the signal was sent by intelligent life.

naturally with all the phenomena that is unknown to us and dealing with background noise that is known to be just noise, your conclusion that it MUST be intelligent life is wishful thinking as long as we have no evidence that it is intelligent life because the source is also observable.



I want to hear what J has to say.


Btw,

Yes, if I was a billionaire I'd like to think I'd be willing to give some money to search for ET.

ant wrote:Just some aliens?
Which aliens?

An unknown subset of the whole.

ant wrote:naturally with all the phenomena that is unknown to us and dealing with background noise that is known to be just noise, your conclusion that it MUST be intelligent life is wishful thinking as long as we have no evidence that it is intelligent life because the source is also observable.

It's not wishful thinking.

To make things easy, we can say the source either intelligent or unintelligent(ignoring for the moment the grey area in between). Unintelligent sources acting within the laws of physics(emissions from spins and orbits) emit patterns. Yet a progression of prime numbers isn't a pattern. It's a patternless yet meaningful signal. So if we run across a progression of primes, it rules out unintelligent sources.

Interbane wrote:

"An unknown subset of the whole"

The whole what? what evidence is there for "the whole" and what experiments have confirmed the whole so as to locate a subset of it?

ant wrote: The whole what? what evidence is there for "the whole" and what experiments have confirmed the whole so as to locate a subset of it?

I have no idea what you're trying to ask. We have no idea if there are aliens. The whole "presumed" set of potential aliens. It's an if/then statement, and aliens are the "then". We can say something if we find a series of progressing prime numbers. Even then, it's an unknown. But at least we would have evidence another intelligent species exists. Although I'd prefer some fancy blueprints to alien technology.

You can participate in SETI by downloading software called Boinc and linking to the SETI@Home project. The software downloads raw data from Arecibo, the huge radiotelescope in Puerto Rico as well as sources elsewhere including the Southen hemisphere. The software analyzes the data in several modes and reports results back to the project. (PM me if you're interested and need help.)

http://boinc.berkeley.edu/
http://setiathome.berkeley.edu/index.php

Interbane asked Would you donate if you were a billionaire? I probably would, but I'm not sure. I'm not much of a gambler.

Paul G. Allen, a microsoft billionaire donated $11.5 million to help start the Allen Telescope Array. This was supposed to start with 42 receivers, 6 X 7 meter dishes as shown below and increase to 350 in phases. The project seems to be stalled at 42 instruments.



A MUCH larger radiotelescope project is in the works. The Square Kilometer Array will be split between South Africa and Australia. This will include several thousand 15 meter dishes and many more low-mid frequency receivers. Linking the two sites together could make the wide-band array work like one huge receiver with a diameter of, well whatever the distance is between South Africa and Australia. Not sure how much SETI work will be done with that system.

In chapter 2, Sagan discusses Einstein gravity waves, which may have a parallel with SETI.

However, in accord with our understanding of human fallibility, heeding the counsel that we may asymptotically approach the truth but will never fully reach it, scientists are today investigating regimes in which General Relativity may break down. For example, General Relativity predicts a startling phenominon called gravitational waves. They have never been detected directly. But if they do not exist there is something fundamentally wrong with General Relativity. Pulsars are rapidly rotating neutron starts whose flicker rates can now be measured to 15 decimal places. Two very dense pulsars in orbit around each other are predicted to radiate copious quantities of gravitational waves - which will in time slightly alter the orbits and rotation periods of the two stars.
pgs 33 - 34

Like signals from aliens, we still have not detected these gravitational waves. Should we stop looking, have we reached a cut-off date? Is this psuedo-science? Why would observing not be considered a necessary part of science?

The bolded section in the quote elegantly highlights a major difference between science and superstition or the supernatural.

By the way, also similar to SETI, you can participate in the search for Einstein gravity waves by downloading Boinc software and attaching to the following project. (PM me if interested and need help.)
http://boinc.berkeley.edu/
http://einstein.phys.uwm.edu/

Like signals from aliens we havent detected gravity waves?

Not a very good comparison.
Actually, its a horrible "this is like that" comparison.

lets all just think about it for awhile.

It's a valid comparison in that you stated because there has been "zero progress and zero evidence for over 20 years" on SETI, it is therefore not scientific. There has been the same level of progress on Einstein gravitational waves in a similar time period, yet I expect you would hesitate to declare that project non-scientific or pseudo-science.

Ant asked Is a hypothesis that produces nothing after 20 years still a scientific hypothesis? Maybe in your heart it still is. In the scientific community, it dies.

Wrong. Einstein gravitational waves and SETI are still scientific hypotheses and are active in the scientific community. Obviously there is nothing in the scientific method stating "You've got 20 years to prove it or it's dead!" We never would have found Higgs-Boson (and many other scientific confirmations or negations) with your standard.