New Paper Offers Additional Reasoning for Fermi's Paradox 774
KentuckyFC writes "If the universe is teeming with advanced civilizations capable of communicating over interstellar distances, then surely we ought to have seen them by now. That's the gist of a paradoxical line of reasoning put forward by the physicist Enrico Fermi in 1950. The so-called Fermi Paradox has haunted SETI researchers ever since. Not least because if the number of intelligent civilizations capable of communication in our galaxy is greater than 1, then we should eventually hear from them. Now one astrophysicist says this thinking fails to take into account the limit to how far a signal from ET can travel before it becomes too faint to hear. Factor that in and everything changes. Assuming the average communicating civilization has a lifetime of 1,000 years, ten times longer than Earth has been broadcasting, and has a signal horizon of 1,000 light-years, you need a minimum of over 300 communicating civilizations in the Milky Way to ensure that you'll see one of them. Any less than that and the chances are that they'll live out their days entirely ignorant of each other's existence. Paradox solved, right?"
Quantum Communication? (Score:3, Interesting)
Civilizations capable of greater levels of exploration would likely have developed means of utilizing communication along the lines of quantum information than our radio waves.
Re:Solved? (Score:5, Interesting)
And if they're communicating by some mechanism that we can't read? E.g. the equivalent of "subspace radio".
Or maybe it's a point to point via laser (see Niven's Known Universe).
Mistake in summary (Score:3, Interesting)
intellgient life... (Score:3, Interesting)
Suppose intelligent life was a super freakish accident, not a forgone conclusion. It took 4-billion years for it to develop on earth. I'll bet it might easily have never happened. And then, there was no reason why we had to develop a technology based culture. That, in itself, might have been a freakish cultural event.
So, maybe, we are pretty special after all.
What if... (Score:1, Interesting)
What if the signal's been there all along, and we've just taken it for granted as a physical phenomenon?
Earth life isn't out there (Score:2, Interesting)
Re:Solved? (Score:5, Interesting)
Maybe there really is no FTL, and other alien races are as leery of sending out giant seedships that they themselves can't ride in as we are, and are thus still hanging out in their home starsystem.
Maybe aliens are everywhere, aware of us, and simply choosing not to communicate.
Disproving aliens deductively is the opposite of science. The lack of easily obtained evidence for alien life is far from damning given the area that we are capable of observing with any real scrutiny.
Re:Solved? (Score:5, Interesting)
True. The calculation of 1000 years seems a bit too long. We can't figure out how to shorten it because we don't know how long we're going to be using broadcast signal based communication as opposed to some other more direct means.
Besides . . . attempting to extrapolate with so many unknowns is, at best, an exercise in postulation. At worst, it is dangerously misinforming.
Re:The First Ones (Score:4, Interesting)
Though it's possible we are the first, it's as likely as winning the lottery. Someone has to do it but the chance of that someone being you is so small that you should first rule out other, more plausible, scenarios.
My favorite is that only the paranoid survive. Civilizations that learn to communicate quietly are the ones that survive. Broadcasting your existence is a great way of advertising 'livable real estate here!' and inviting other civilizations over for a look see. Not too smart if it turns out they end up wanting your planet.
Re:It's quite clear what the reason is (Score:5, Interesting)
Actually, IIRC, the Pope made a declaration a while back that there's nothing biblical that bars the existence of extraterrestrial life. For many people who are strongly devoted to one religion or another, even finding a note from their messiah announcing "Just kidding - I didn't think that y'all were going to take me so seriously. Hopefully after I die, somebody will find this and avoid any real disaster," would defer them from their beliefs.
Re:Solved? (Score:3, Interesting)
other alien races are as leery of sending out giant seedships that they themselves can't ride in as we are
I don't think humans are particularly leery of the idea of getting on a starship. And even if 99% of humans have no interest in getting on a starship, that leaves ~70 million perfectly willing volunteers. Give it another few hundred years of technological advancement and we'll be able to contemplate something large enough to be a "generation ship", or place the travellers in suspended animation, or some other trick to make the lengthy trip survivable.
Re:Solved? (Score:5, Interesting)
Assuming you can't skirt around the light barrier then that basically means sending small groups of people (or aliens or whatever) across trillions of miles, probably in some kind of hibernated state, in the hope that they'll bump into a habitable somewhere, set up shop, and begin to populate. Any returns on investment will be very intangible indeed- physical goods have to come back the same way they came (meaning it would have to be extraordinarily valuable to merit the shipping and handling on an interstellar ark) and information is cheap. You'd need to expect a very valuable treasure-trove of knowledge indeed for information to start making sense as an expected ROI.
I know many people just assume that interstellar travel is the "next step" in the development of societies but the longer I look at it the less it seems to offer tangible benefits for the people who have to invest in this.
I expect a society thinking in the long-term would obviously see the benefits of spreading one's seed across multiple star systems... but you have to postulate the existence of a society that takes the long view. Considering how easily a society as advanced as ours (not saying we're very advanced: just a society at the same level of advancement as us) is busily undermining its own biome, knows it's doing it, and doesn't care, and took pains to smother other societies which might have taken the longer view, I don't think we should expect many societies to reach the "long-view" stage before they wiped themselves out or got wiped out.
Re:intellgient life... (Score:4, Interesting)
Except that intelligence doesn't necessarily take 4 billion years to evolve. It's not a nice, clean timeline. The real hurdles were evolutionary events like the spark of life, sexual reproduction (leading to more mutations), and multi-celled organisms. Evolution, through nature's nasty tendency to wipe the slate clean, has to keep taking steps backwards. Dinosaurs lost their place on top of the heap after 100s of millions of years of dominance and 65 million years later we have intelligent life.
Imagine if there are worlds where there are fewer extinction level events or environmental factors that favor jumping the hurdles sooner. We just don't know enough about other planets to know how long it takes for intelligence to evolve.
Re:But if that's right... (Score:3, Interesting)
I posted this in January 2005:
Drakes formula allows some kind of estimate as to the number of intelligent societies there might be "out there".
The following is from a great book by A.K. Dewdney: Yes, We Have no Neutrons.
The formula is N = R* x Fp x Ne x Fl x Fi x Fc x L
For which:
R* = number of new stars that form in our galaxy each year
Fp = fraction of stars having planetary systems
Ne = average number of life-supporting planets per star
Fl = fraction of those planets on which life develops
Fi = fraction of life forms that become intelligent
Fc = fraction of intelligent beings that develop radio
L = average lifetime of a communicating society
The formula has appeared in several popular science magazines with the values set to:
N = 10 x 1 x 1 x 1 x 0.01 x 0.1 x L
So, N = 0.01 x L
The only numbers in the formula which anything other than a guess can be made are R* and L. Based on current observations most set R* at 10. Everything else in the formula would be a wild guess, except for L. More is known about L than any other part of the formula, since we are a communication society. Since we receive more and more of our communication from satellites, cable, and the internet, we are broadcasting less and less away from the earth. In the near future we will likely go dark as a significant source of radio/broadcast signals capable of being detected from space. If we say that our source of signals is about 100 years, drop the 100 back into the formula and you get 1. That must be us.
Re:Is there stuff in space that acts like rain fad (Score:3, Interesting)
Imagine holding up a lit LED on top of Mt Everest. How far away do you think you'd be able to see that, even assuming clear viewing conditions.
Now back off and imagine how far away our sun would be easily distinguishable from every other star in the milky way. The closest neighboring star to us isn't even the brightest star in our sky.
Compared to our sun, all of our communications are on the level of that LED on Everest. That will give you an idea of the likelihood of spotting a signal from any distance, even without the background noise.
Re:Solved? (Score:2, Interesting)
Re:It's quite clear what the reason is (Score:4, Interesting)
Re:It's quite clear what the reason is (Score:5, Interesting)
(Except of course that all the dates for the signs are fixed as they were in the time of the Ancient Greeks, so we're already off by a whole month. If you're a Libra the sun is actually in Virgo on your birthday.)
This also means that the autumnal equinox in 4004 BC was somewhere around the end of June.
Extraterrestrial life may become a boring topic (Score:3, Interesting)
Re:Too many unknowns (Score:3, Interesting)
Sure it is. It's just not a good one.
Douglas Adams quote (Score:2, Interesting)
"Space is big. Really big. You just won't believe how vastly, hugely, mind- bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space." -- Douglas Adams
I'll include some explanation. We've been dealing with science fantasy (I'll define that here as fiction that uses scientific sounding explanations of things for purposes of adding credibility to fantasy stories but which isn't exploring actual science) for years. The best of it points out somehow that it has some cheat (like the spice Melange or the Heart of Gold) that changes the rules of interstellar travel.
Because currently, without finding a way to cheat, those rules are ironclad and depressing, and basically mean that the nearest star is out of reach as far as we know, let alone zipping around the entire universe at will. How would you even navigate in something that vast let alone actually travel it?
It makes the question of extra terrestrial intelligence a question along the lines of a Medieval Churchman speculating on the number of angels that can dance on the head of a pin. A sort of interesting philisophical discussion but not much more than that.
For the record, I believe with metaphysical certainty that both extra terrestrial life and extra-terrestrial intelligence exist. I also believe with the same certainty that I'll never have any proof of that either way.
Fermi's paradox which boils down to "Where are they?" is living in fantasy-land. You want to know where they are? I'll tell you, "You can't get there from here."
Alternate solution: High-efficiency communication (Score:5, Interesting)
The calculation of 1000 years seems a bit too long. We can't figure out how to shorten it because we don't know how long we're going to be using broadcast signal based communication as opposed to some other more direct means.
My own contribution to the debate:
As technology advances the limited amount of available bandwidth becomes more valuable, while costs of utilizing it drop. The civilization migrates its bandwidth use from simple, extremely redundant, coding schemes (like AM and FM) to subtle, highly-efficient schemes that are virtually indistinguishable from thermal noise (like OFDM). They also use spacial multiplexing to re-use the same bandwidth over and over at various locations. This buries the few redundant parts of the signal (like the pilot subchannels used for synchronizing the receiver) in interfering noise.
The result is that, after a fairly short time, at a distance they are virtually indistinguishable from a hot black body - and lost in the sagans of other hot things in the galaxy.
Our first AM voice radio broadcast was at the end of 1906. 102 years later we're taking a big step in the transition to OFDM-or-CDMA-everywhere by shutting down "analog TV" and replacing it with OFDM-based digital. AM and FM are already using digital variants to squeeze more out of their spectrum. Any bets on how long until they switch, too?
Once the simple-modulation blowtorches are switched over the few remaining detectably-patterned signals will be soft voices crying in a wilderness of high-noise-floor. If we don't DELIBERATELY send some intended-to-be-noticed beacons we'll again be lost in the background - our own and the galaxy's.
A thousand years? In our case the detectability sphere looks to be only a tad over 100 years deep.
Don't blink!
Re:intellgient life... (Score:4, Interesting)
Good points, to which I want to add, that intelligence does not necessarily lead to radio waves at any eventual point.
Radiowaves are a social phenomenon. They are used to communicate between beings of shared language over large distances in short amounts of time. This means that there is a need to communicate quickly, and natural methods are insufficient. For example, whales are intelligent and communicate over great distances. Yet they have no need for radios because the water medium is good enough for their needs.
Animals are capable of using magnetism to coordinate. Be it distance migrations or short-distance homing. Avian/IP takes this into consideration. If they found a way to communicate naturally via the magnetic material in their heads (over short distances - telepathy) they could pony express a message throughout their habitat at relatively low time cost.
Then even if they had the motivation or understanding they still need to be physiologically equipped to construct a device. And that device needs mining and metal refining technologies.
So while there may me the means, there may not be the motivation for the mega an giga-watt broadcasts we currently use.
I expect that if we ever get exploring other habitable worlds, we'll find a lot of life to interact with in complex ways, but are technologically inferior due to physiology. I call this the "cephalopod argument". That is, they seem to be relatively intelligent creatures, while sharing little to nothing in common with our nervous system. They've been unchanged for millions of years, without additional evolutionary selection criteria, they have no reason to change. (Also, until we can communicate with them we are unlikely to be able to communicate with ETs unless they provide the means)
Do we want to be found? (Score:4, Interesting)
Why are we soooo certain that we *want* to be found? I personally would prefer not to be a slave or a menu item to another race of beings. Honestly, what makes you think they will be peaceful or even tolerant of our existence if do find another civilization?
2 cents,
QueenB
Re:Solved? (Score:5, Interesting)
Re:Solved? (Score:3, Interesting)
That is a grotesquely 20th century view of interstellar colonization. It may or may not be on the edge of feasibility with fusion-based propulsion, it probably is with implausible anti-matter propulsion, but it's quite questionable whether it works physically, let alone economically.
What is way more plausible is something involving a nanotech-based seed that can start up a virtual society that fits easily within a few kilograms of payload. That seems feasible today. That doesn't seem like something we could build today, but it involves no fundamental breakthroughs in physics. This would tear apart the entire target solar system and turn it into computronium.
Two things come out of that: First, this should have happened before there was any interesting life on Earth to be ethically worried about, assuming such beings would even care. Second, we should be able to see the outcome of such radical changes as the entire solar output of stars would be used. But we don't. We just see stars.
This doesn't resolve the paradox, because our understanding of physics still says at least one civilization should have gotten to this point, and once they do, a wave of near-lightspeed colonization should still occur. (Where "near-lightspeed" may still be 10% of lightspeed or something; on this scale, it doesn't matter.) It turns out "colonization" looks nothing like it does on Star Trek, but it still is colonization and we'd still see it, if not in actual "communication". But we don't.
The Fermi paradox remains. These sorts of explanations show it to be a deeper problem than they understood in Fermi's time, but it remains. Is there something wrong with our understanding of physics? (Is the max computational limit far lower than it seems, by many orders of magnitude? Is there some easy way to build a pocket universe such that all civilizations, with 100% totality, choose to escape into a pocket universe rather than colonize this one? If so, we have no hint of that in our most sophisticated theories.) Is there something wrong with our understanding of the universe? (Are we simulated? Maybe something did colonize our solar system that way, and for ethical reasons chose to simulate all future life on Earth while they tore our solar system apart for their own needs. This could even have happened a bare few years ago in real time, even as the simulation crossover point could well have been millions of years ago subjective. Is there actually some sort of superior being preventing this from happening, a god, a God, or some sort of Saberhagen-style Berserkers? Is life or intelligent life or evolution profoundly less likely than we think it is?) As my parentheticals indicate, there are still many possibilities, but in my opinion, the Fermi paradox remains a profound challenge for the conventional, secular humanist/athiest, WYSIWYG-view of the universe. (And I do mean "challenge", not "disproof".)
Re:It's quite clear what the reason is (Score:2, Interesting)
Many Christians (and other theists, for that matter) think that evolution at all conflicts with theology. God created everything perfectly (man in his own image after all) the first time, and nothing changed after that. After all, God's image is perfect, isn't it?
Even for creationists, how would finding life elsewhere prove them wrong (maybe they already conflict with science, sure, but I'm referring to just finding aliens)? They could simply say that God created the aliens too. "In his own image" obviously doesn't mean physical appearance, because then everybody would look the same, right?
Christianity and extraterrestrial life just don't seem to be mutually exclusive, but for some reason everyone thinks they are. I once heard a big-time intelligent design guy give an entire 2-hour lecture on supposedly scientific reasons of why there can only be life on earth, because he felt that life elsewhere would prove that Christianity was bogus, but he never gave a good reason why he felt that way.
Re:It's quite clear what the reason is (Score:3, Interesting)
If you take the creation story in Genesis metaphorically (lots of Christians do),
You can't do that if you're talking to Americans, which most of us on Slashdot are. Here, most Christians believe the literal story of Genesis. What the pope says is irrelevant, since most Christians in America believe Catholicism to be a false and non-Christian religion.
Re:We can't talk to Dolphins (Score:3, Interesting)
The supposition is that we have the corner on intelligence. It's clear that Dolphins have a sophisticated and elaborate social construct that requires exacting communication to maintain. This appears from my vantage point to be evidence of intelligence. However there is a certain hubris to human intellect that assumes that if we can't understand it that it's not intelligent. Orangutans were intelligent enough to speak in sigh language before we taught it to them, however 50 years ago you would have been laughed at to suggest they would be capable of even their limited ability to hold a conversation.
The further we get from human forms of communication the more likely we are to disregard a species of having intelligence simply because we can't understand it.
Re:Hmm (Score:3, Interesting)
In the real world, exponential growth always hits limits. Why should technological progress be any different?
Re:Solved? (Score:4, Interesting)
First,you assume interstellar travel is possible. What if it isn't? What if the only ways to travel in space are no much better than the ones we know? We'd be all restrained to our own star systems. Perhaps we can have space stations and colonies in nearby planets and moons, but not much more than that. Perhaps they can't be self sustainable. Perhaps the likehood of finding another environment in another planet that can be converted to supporting life without an extreme expense of energy is extremely low.
AFAIK, the Fermi paradox has nothing to do with interstellar travel. It only assumes things that we already know, and hence are definitely possible - using radio waves as a means of communication. I myself think this may be too much of an assumption.
Re:Too many unknowns (Score:3, Interesting)
Re:Do we want to be found? (Score:4, Interesting)
Or to put it in terms of Fermi's paradox: Maybe the galaxy's other 5000 intelligent civilizations are all keeping quiet because they know what's out there -- and it ain't friendly.
Maybe we're an entire civilization of stupid newbs wandering naked and lonely in a forest full of predators, shouting "Heloooo! Anyone home?"
Re:It's quite clear what the reason is (Score:4, Interesting)
Summary:
A) Aliens come to eat us
B) Aliens might contradict our world-view
C) Aliens probably can't/won't communicate with us, so it just adds more inconclusive doubt. Which only brings us pain.
D) To non-believers, aliens represent an 'I told you so!!!' moment.
E) Believers are put-off by the 'I'm sure I can say I told you so!!!!' movement
Details:
Great question. But here's my take:
You might vote republican because it's pro-life, anti-stem-cell-research, anti-gay
You are pro-life/ anti-stem-cell because abortion is soul abuse
Abortion is soul-abuse because 'God says so'
'God says so' because that's how you were brought up. (Killing is wrong) - (even though it's technically Murder that is wrong - specifically subject to human interpretation)
You know that's how you were brought up because you and your peers are reminded of it in church weekly.
Your church is right because it is 2,000 years old. (or otherwise derived from an Angel affirming the truth to 1 recent historic figure)
So now if you start showing how your church was historically wrong, you can start backing out the logic until Christopher Reves can be saved!!
Obviously you're stuck until the 'feeling right' part is overcome. Religion is more-often a justification for your personal world-views. That's often why people change their religion.
So Lets take a separate path.
The church is correct because it 'feels' right [to me].
The church might feel right because of its simple mantra: Jesus Christ is my personal savior.
Jesus is my personal savior because I need to be saved.
Jesus CAN save us because people say he performed certain random semi-useful miracles (though 60 to 100 years after the events)
I need to be saved because I'm a sinner.
Alternately, I need to be saved, because I'm insecure and need to feel the safety net of a super-power taking care of me during my time of need. There is no biblical justification to this. In fact, Jesus parables specifically contradict this (believers are destined an even harder and more arduous life). It is always people that perform miracles in the New Testament. Natural miracles were part of the old Testament. People were later embued with Jesus-like-powers. Yet they weren't saviors themselves, just messengers who re-affirm the gotta-believe-in-Jesus mantra.
I am a sinner because I screw up a lot (Great 4,000 years ago, but doesn't sit well today, so lets try again)
I am a sinner because of original sin.
Original sin exists because of Adam and Eve.
Adam and eve exist because of the bible is the word of God and is NOT metaphorical. It is a historical record guided by the hand of God, and worthy of extrapolating truths by reading in between the lines.
So miracles aside. So now if you start mucking with the truths of this or that, you obviously can't read in between the lines. A sane/rational person thus would ignore ALL texts not explicitly outlined when presented with factual errors in the bible. Though original sin and homophobia are clearly layed out - so you could still argue that point. Most people, however, will still read in between the lines when it's convenient to promote their cause (cognitive dissidence).
For example, homosexuality is one of MANY punishable by death sins in the old testiment. Put right next to eating a cheese-burger. Yet we 'ignore' the cheese-burger death-sentence through the 'personal savior' clause - fulfilling the old testament.. Yet even though Homosexuality is a death-filled God vengence, it is never mentioned again in the new testament, it's conveniently allowed to survive, while cheese-burgers are silently acquitted. Ultimately 'common sense'
Several Alternatives for Fermi's Paradox (Score:3, Interesting)
First of all, the entire reasoning is flawed.
It simply makes no sense, what so ever.
My case and point: Radio technology.
Now, I have used radio technology quite a bit. I have to say, I am not impressed so far.
Seems slow (Its a dog for wireless G, and well...can't get decent wireless N drivers for Linux because of greed, and patent problems in the US...etc, probably still is dog slow.)
Now, why would, a intergalactic civilization, use electro magnetic waves, to communicate, over a distance of hundreds of light years?
Sort of seems, well, impractical doesn't it? Yet, all of these learned people insist that is the ONLY POSSIBLY WAY TO DO IT. Sort of seems oxymoronic too. Somehow the intergalactic civilization can conquor huge distances, but can't even say hello to each other from one end of the empire to the other end?
It is just stupid no matter how you argue this point. Not only that, but I am going to rightly assume I think, that any civilization that comes into being, has to operate on at least some of the same principles as our civilization. You cannot coordinate advances in a galactic empire with such a system as using radio, it is too slow for the distances.
Remember the horse and buggy? That is what I compare radio too. Is there something better? Well, people during that day didn't think so. It was simply impossible to better than the horse and buggy.
Why? Well, because the leading scientists of the day said so.
Luckily the idiots all died out, eventually clearing the way for well, people who had a little bit more imagination. (That and their tenure was now up for grabs and people could now introduce new rigid ways of thinking.)
It just so happens some of those rigid, unoriginal ideas included the steam engine and well...greed.
What is the only way to send signals instantaneously without distance becoming a limiting factor in todays world?
Do we know of any such system today?
Well, yes we do. But, I won't mention it here, because it is at the very leading edges of computing and you will just have to look for yourselves. But it involves tapping unseen states of matter which exist outside time and space.
But, as I point out. Radio waves would be a totally useless system to use. Nobody seems to point that out, UNLESS of course we consider the other side of the Fermi Paradox.
Which basically is, since using electromagnetic signals is really stupid, and since a civilization of vast galactic means would not use them, and they are not here.
It is entirely possible they simply do not exist.
That is a scary thought.
I prefer the alternate view though. Why? Well, Earth cannot be that unique. I mean, I am willing to at least entertain the idea that in the entire galaxy, let alone the UNIVERSE, there was another planet, that came to pass with similair traits and that:
1) A very advanced civilization really does exist.
2) Like the horse and buggy, they over came all obstacles to thinking and discovered the secret of travel, outside space time, to any point and any place in the Universe.
Given the SIZE of the universe, here is where I believe the Fermi Paradox falls flat on its face:
If you could go anywhere in the Universe, why in the hell would you come to a planet like earth with retards on it?
I am serious. If you could travel the entire universe and utilize communications that had no problem with distance, in fact, distance and time was entirely NOT PART of the transportation system, how long would it take you to eventually come around to the earth?
I ask this because it would seem to me, once you discover such a system, keeping yourself confined to a single galaxy is dumb. (i.e. The Drake equation should really be recalibrated to the entire Universe, not just the galaxy.)
I mean, it is sort of like this: Once you invent the airplane. Would you SERIOUSLY restrict yourself to your little country? No, of course not, you would get in the pl
Re:I always thought SETI was a fools errand (Score:3, Interesting)
SETI is looking for narrow band RF signals and some optical pulses, . They wouldn't likely even detect a digital spread spectrum transmission, much less whatever type of transmission optimized for interstellar communications that we haven't even thought of yet. In fact, their site says:
SETI researchers look for narrow-band signals, the type that are confined to a small (usually 1 Hz or less) spot on the dial. But if you have a cellular phone, you may be aware that a lot of communications on Earth are now done using a technique known as "spread spectrum." The broadcast signal is dispersed over a wide range of frequencies. What if ET is also engaged in spread spectrum broadcasting? Would our searches pick up his call? That depends. If the signal is strong enough, it might still be detected with current SETI equipment, although weak broadcasts will be missed. There's little doubt that in the future, with greatly increased computer capability, our search will encompass these other types of communications.
http://www.seti.org/Page.aspx?pid=558#WrongType [seti.org]
Who wants to bet that when ET phones home that they don't bother pointing a powerful constant carrier wave at Earth while they're doing it, but instead make it very much point-to-point directional and use signaling techniques that we haven't thought of...
Re:Do we want to be found? (Score:3, Interesting)
You know that is REALLY good thinking.
I could imagine the same thing happening. Any race that is smart enough to travel here on their spaceship is probably smart enough to figure out that we actually have nothing of value.
And like you say, "hey we are a warlike race". I would add a race that all believes we have the one true religion and one true philosophy on how life was created, yada, yada...
The problem is that a dozen religions all seem to believe the same thing...
If I were the Vulcan race I would say, "oh wow, let's move on and see if they are still around in about 100,000 years." If so maybe then...
Re:It's quite clear what the reason is (Score:3, Interesting)
We may not be able to translate dolphin language, but we can tell it contains non-entropic information. In other words, we can at least tell that they have a language.
Information theory can tell us whether or not there's a message in the data, with a fairly high probability. That doesn't mean we can transcribe it.
My guess is that loud radio waves are a primitive form of communication. We already know that we can transmit information in better ways, and use the spectrum in better ways, and use less power to boot.
We just haven't done it. We're like a 16 year old kid barreling down the highway with the windows down and the music all the way up. I don't think it's very good security, really. It's basically security through obscurity for Earth. We're too far away for it to matter, we guess .
A sufficiently advanced civilization probably knows better, and has probes out here sending back quantum entangled messages instantly, about our local shit. At least, that's what I'd do, and I'm just a monkey.
Re:It's quite clear what the reason is (Score:3, Interesting)
Not really. It's that they only broadcast for less than 1000 years. In less time than that they switch to cable, or fiber optics, or something else that can't be heard at a long distance.
The Tipler problem is harder, though. If anyone built self-reproducing cosmic explorers, then it should take them only a short time to get here (assuming that they reproduce more quickly than they get destroyed). Of course, whether they'd tell us they were here is a very different matter. And so is how they'd communicate to back home. (Exploration robots don't do much good unless they report back occasionally.)
So maybe we will find a pyramid on the moon, or something hiding in Saturn's rings. Perhaps. (I liked the short story better than the movie.)