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From the SETI website?

After twenty years of scanning for radio signals, and countless trillions of processor cycles, it?s refreshing to see SETI looking at other possible ways that extra-terrestrial intelligence might be trying to attract our attention. However, what are the chances of intercepting one of these ?very brief flashes of light?? Time and space would seem to make such an interception extremely remote wouldn?t they?

Advanced ETs may use MFFM radio for their own communication because it is more efficient. A coarse discriminator will see just a minor white noise spike. If they are thorough They could deliberately use an obvious open pattern to flag anybody including newbies at who just developed parabolic dish antennas.

Aloha, Charlie

You ask:
>>> Is SETI Too Focused On The Electromagnetic Spectrum?


Which other spectrum would you suggest?

Somebody just read "The Mote in God's Eye."

Biven a civilization with the leisure, wealth, technology, and desire to tell others it has arrived. That is already a stupid idea. The wealthy keep a low profile lest the poor and motivated show up to seize a fat piece.

Remarkably, you it doesn't have emitters between deep radio and short microwave. Will it pop a laser at selected targets? First, it's a stupid idea: One target/emission. Second, it's a stupid idea: What if they are looking the other way when the light pulses arrive?

Third, there is no reason for SETI to seek unnatural IR or visible emissions against a star's background emissions. Standard astronomy, expecially the search for exoplanets, is already busting its hump exactly doing that to incredible sensitivity.

Here's the straight skinny: Physics is the same everywhere. High-powered (megawatt) radio and microwave are available to even primitive cultures. The Earth is sitting at the center of a loud EMF bubble more than 60 lightyears in radius. That is 905,000 cubic lightyears. We've already sent out our calling card. Nobody has RSVP.

SETI sees nothing. Perhaps technological civilizations very rarely arise. Perhaps they are common but suffocate themsleves in eventual compassion, diveristy, and god - losing the cutting edge that elevated them from the muck. The universe is undoubtedy dripping with life, almost all of it no better than sub-Saharan Africa.

When Terran First World civilization crashes between 2015 (Baby Boomer retirement) and 2050 (end of petroleum), it is not coming back.

If you look at the size and time scale of the universe there would be only a small, very small, percentage of the known universe that would be at or near our technological development level.

That means that most of the sky would be devoid of any electromagnetic spectrum communication.

The weakness of any signal not directed straight on at earth would mean that it would take an extremely sensitive reciever aimed with absolute precision to even have a chance of recieving such a signal.

I also do not think any truly advanced and inteligent species would be using any means of communication that is limited by light speed.

Think about it, even at a distance of only ten light years it would take twenty years to send and recieve a two way message.

I think when we finally figure out how the peoples of the universe are actually communicating (assuming that there are "peoples of the universe") we will find they are using something akin to the paired particle phenomenon.

That is where you have two particles emitted simultaneously with opposite spin characteristics. Then when something happens to affect the spin of one of them the other will be affected immediately no matter the distance; seemingly violating the "light speed limit".

If you could affect the right particles the right way and then detect the change in their pairs you would have "faster than light" communication.

I am not saying this is what we will find, rather - that it would have to be something of that nature that provides FTL communication to be meaningful and useful to any beings of an extremely advanced culture that happen to be out there.

Some bold predictions from SETI dude Seth Shostak in today's paper....
http://www.theaustralian.news.com.au/common/story_page/0,5744,15847967%255E29098,00.html

I wonder where he gets these figures from?

Probably from the voices in his head. Otherwise it is just poorly constructed stastical analysis.

Or as Samual Clemmons said.......

There are three kinds of lies; plain lies, damn lies, and statistics.

Kate:"I wonder where he gets these figures from?"

Lets's see. For question two, there is the (in)famous Greenbanks equation, developed around the '80 (I think) by Sagan, Drake, Hoyle and the likes, which gives the number of probable civilizations in the universe, depending on several probabilistic factors. Depending on these "fudge" factors you can get anything from 100-10,000,000 civilizations scattered across the universe. And very likely, they have refined the estimations since the '80's.10,000 looks like a reasonable number.

For the second question, there is nothing like staistics, is it? For an observable universe of roughly 3,000 Mpc, and 10,000 civilizations scattered through it, that would give an average distance(well, not quite average in this case, but you get the ideea) of ~0.3 Mpc to a civilization. Fudge in the fact that say Andromeda is ~ 1Mpc away, also when a civilization might have strated to spew elmg radiation (if you go by when we started, the date should go to ~3025 instead of 2025), and you get something below the year 2050-2100. factor in whisful thinking, the necessity for funding, and you will get to 2025 or similar.

According to this article one should expect that the universe is full of intelligent creatures. This seems to be in conflict with anthropic reasoning. Most civilizations must have spread throughout their galaxies containing huge number of observers, so the typical observer is a member of a galactic civilization. So, contrary to anthropic reasoning, we don't seem to be typical observers.


An explanation might be that it is cheaper to explore space by developing intelligent machines then using humans. So, once a civilization starts to explore space, intelligent robots arise that then take over and replace the biological creatures. One then has to explain why we are biological beings and not machines.


It could be that the assumption that a galactic civilization typically contains a very large number of observers is false. Intelligent machines won't have difficulties merging their minds and perhaps a typical machine civilization consits of only one observer.

Hey Ibliss, long time no see.

Come on, you know how these things work. You need a time scale for the spread of a civilization, you need a length scale for the spread of a civilization, and after you get these somehow, you must remember that the anthropic principle has been developed locally (i.e. because WE exist)and we have no clue if it is globally valid. And BTW, the spread of a civilization somehow invalidates by itself the anthropic principle, unless you only consider the "seeds".

BTW again, are you going to the LQG conference in Potsdam?

Hi Pasti,

I'm not going to Potsdam, Quantum gravity is a bit outside my field... I'm actually too busy finishing my Ph.D. thesis and also with doing some other research. I've already done too many different things besides the research I was hired to do for my Ph.D. thesis. This isn't too bad because no one is going to read my Ph.D. thesis anyway. Only the publication list matters.


About the AP, I agree that we don't know for sure how we should apply it. I know you take a more agnostic point of view on these matters. I like to explore the consequences of certain well defined scenarios.

E.g. suppose that you have an infinite universe which is homogeneous (on large enough scales). All possible states will then occur infinitely often. The paradox Olum is talking about arises in this setting.


I don't see how the spread of a civilization invalidates the anthropic principle. Are you referring to the doomsday paradox? Olum has also written an article about this, showing that this paradox arises when people incorrectly apply Bayes's theorem (actually this is a result due to D. Dieks).

Well, it promises to be a nice conference. Even if it isn't quite along your field, it wouldn't hurt to atted it. Sooner or later you should takle this part of QG too. Maybe you should reconsider, it is 4 days only anyway.
BTW, I'd like to read your thesis, when it's ready.

As for the matter we were discussing, I am not any more agnostic than you are, if we are to stick with the literal meaning of the term. As for the anthropic principle, we don't even know if there exists something like that yet. It has been postulated on a unique example. It is as if one would say you can only draw a line through two points. Plowing the field in circles does not mean recording an LP. Once we don't know wheter it exists, its application is just a matter of intelectual exercise, without (too much) factual basis. Sure, you can investigate many possible scenarios arising from such an ideea, but to what finality (except intelectual satisfaction, of course)?

So consider the infinite homogeneous universe. What if the anthropic principle is compatible only with the (long range) equilibrium states (Pasti's Anthropic Principle) which are not affected by short range nonequilibrium, like tthe appearance of a civilization like ours?
Olum states quite clearly that either the inflationary picture is wrong in the anthropic context, or the anthropic picture is wrong in the inflationary context. Now apply Occam's razor.

No, when I said the "seeds" I meant evolutionary process from anorganic to organic to life, etc (panspermia in a more generalized sense), and not
to civilizations that are offsprings of other civilizations, because such offsprings could develop in "locations" where the anthropic principle would be invalid (could create habitats where life could not evolve naturally, hence the invalidity of arguments based on the anthropic principle also (though the offspring issue would imply at first sight that there should be more civilizations/larger spread than predicted by the anthropic principle).

Perhaps you're right Yogi. The figures are perhaps more about getting funding from daffy squillionaires than representing a cogent estimate on the number of ET civilizations.

Unfortunately, the daffy squillionaires are us. Most of the SETI research is funded through straight government grants or second hand through grants to organizations and universities. The cost of these programs are way too high for philanthropists to make much of a dent in their budgets.

If you go a little further back in this thread and read my previous post you will get a sense of why we are not really very likely to find anything with the SETI project as long as they are looking in the limited to lightspeed electromagnetic spectrum.

I'll think about it!

I am actually more inclined to think that one should apply the AP (in principle) to single observers in some given state. The laws of physics as we know them are local and allow you to calculate (in principle) correlations between observables. But when you do an experiment what you are actually measuring are correlations like:


Probability that Pasti finds outcome X in experiment Y.


I.e., it is something that refers only to your own state at some given moment (you remember finding X a fraction q of the time you did experiment Y). In the limit that you do the experiment infinitely often you should find the result predicted by QM. But this implies a nontrivial statement about how the probability distribution over Pastis in certain states should tend to a limiting delta function.


So, the validity of anthropic reasoning is already implicitely assumed when we do experiments to test theories. I am thus inclined to think that Olum overlooks some possibilities when he concludes that ''either the inflationary picture is wrong in the anthropic context, or the anthropic picture is wrong in the inflationary context''. In particular he makes assumptions about how civilizations could spread the galaxy and how that would lead to an enormous number of observers. I think that this scenario is highly unlikely, so unlikely that it cancels the huge ratio of

''galactic observers''/''terestrial observers''

Olum already mentions uncertainty in assumptions about how civilizations evolve. I think that that is the clue. Sooner or later we can make artificially intelligent beings that are not limited by our biological limitations. It is clear to me that they and not we will perhaps colonize the galaxy.

I agree with you in regard to the assumptions Olum makes. The result is not surprising since assumptions a la Sagan/Greenbanks equations are more a matter of consent among people rather than empirical evidence.

As for the AP/anthropic reasoning, if such a principle indeed exists, I agree with you that it should be manifest in testing the theories and in developing the theories. But then, there is no empirical evidence for such a principle nor is it required for any kind of explanation. If you look at the origin of this principle, the principle is similar to the manner in which Alexander the Great solved the Gordian Knot problem. It states without explaining (as any principle does), but in a circumventional manner (it is self-supporting).
To my taste at the very least, this principle is no better than stating that we don't know why life exists in this universe, on this planet or in this form. And I don't see any reason why we shouldn't be able to answer this question in a (more than less) distant future. In this view, the principle is merely an illustration of human impatience when it comes to understanding, and as such, a subjective statement (of course, you can claim this is in fact anthropic reasoning...)

But what surprises me, and I might be wrong about this, is that I haven't seen any attempt to verify such a principle on the better known evolution of life/history of civilizations here on Earth. I am pretty sure that the AP could be adapted to the ultralocal conditions and circumstances of life on Earth, and yet I haven't seen any studies along these lines. But maybe I am wrong, since this not exactly along my field of expertise.

It would only make sense when talking about a civilization far superior to us. It wouldn't make sense for beings, that say, conquered galaxy to galaxy travel to use communications only at the speed of light. At that rate they might as well not even send a message, since they'd be home years before the message ever got there.

The distances are huge.
And it is not logical assume that any advance species will use light as the means of communication.
Before communicating with any advance species we will have to understand few concepts:
1.What is meant intelligent communication and chaotic communication?
2.Is it possible to commuincate instantly and allow decoding to take place at speeds equal to light?
We will have to look at Qunatum Physics and others dimensions for better answers...
here are few more questions...
Arent they already communicating with us?
Are they not influencing our behaviour in the most subtle forms?

Nice response dkv.
In a way, they "influence" us without even being here. Opening yourself and actually participating in "the search" changes people. It has in my case, anyway.

True. And I wont dispute that.
But I wish to draw attention to the inherent limitations posed by the large scale space time configuration.And it is more logical to believe that it will take a very very long time to find and understand any such intelligent electromagnetic communication.The next Advanced species could possibly know how to communicate through the Universe wihout traveling entire distance defined by our large scale Universe.
And then there is a natural decay of the signal due spread and various other reasons.
Throwing radiation in the Universe is like making the information travel on the surface of the sphere.

There can also be psycological reasons associated for not revealing their true identity.
If they are very weak and peace loving then they will not like to come in contact with humans.As as we dont like to go into the jungle.
And finally we need to understand what is meant by communication.

Yeah, I wonder how "open contact" would actually work. I doubt the whole 'landing on the lawn by the white house' theory. Atleast not without 50 fighters trying to blow them out of the sky first. That would only go very wrong very quickly. I agree with the whole peace/loving statement you made.