SETI vs METI Dispute: Lions and Tigers and Bears – Oh My
We just sent a message to try to talk to aliens on another world, New Scientist
“Ninety-eight percent of astronomers and SETI researchers, including myself, think that METI is potentially dangerous, and not a good idea,” says Dan Werthimer, a SETI researcher at the University of California at Berkeley. “It’s like shouting in a forest before you know if there are tigers, lions, and bears or other dangerous animals there.”
Scientists Have Sent Messages to Advanced Civilizations, Newsweek
“[Douglas Vakoch, president of METI] Everyone engaged in SETI is already endorsing transmissions to extraterrestrials through their actions. If we detect a signal from aliens through a SETI program, there’s no way to prevent a cacophony of responses from Earth. And these wouldn’t be responses to a possibly habitable exoplanet, but to a star system where we know there is intelligent life. There’s no way to enforce the SETI protocols that call for consultation before replying. Once the news gets out that we’ve detected extraterrestrials, anyone with a transmitter can say whatever they want.”
Declaration of Principles Concerning the Conduct of the Search for Extraterrestrial Intelligence (2010 protocol), SETI Permanent Study Group of the International Academy of Astronautics
“8. Response to signals: In the case of the confirmed detection of a signal, signatories to this declaration will not respond without first seeking guidance and consent of a broadly representative international body, such as the United Nations.”
Keith’s note: This is all rather silly. SETI scientists like Werthimer would prefer not to transmit anything to anyone. But they want people to give them millions of dollars to listen for transmissions from other intelligent species. If alien intelligences are similar to us i.e. afraid of other letting civilizations know where they are then they are not going to be transmitting either. If that is true then Werthimer et al are wasting a lot of money listening for signals that are not going to be there – if you follow their self-canceling logic, that is.
Also, Wetheimer claims his statements are shared by “Ninety-eight percent of astronomers and SETI researchers”. Really – he has polled all astronomers and SETI researchers – everywhere? Reference, please. We have been announcing our presence to alien civilizations in one form or another for nearly a century via radio. The bulk of these transmissions have not been done by governments. As such the 2010 statement by IAA (which is also utterly non-binding) would have little effect on stoping anyone with money and a big dish from saying “hello”.
On the other hand, just because someone can do something does not mean that they should. This topic needs a broader airing – not just food fights in the news between dueling METI/SETI sandboxes. Both the SETI and METI tribes are myopic, and somewhat inbred, by definition. Their pronouncements from on high should not be the final say on the way that humanity deals with this topic. There are 6 billion other humans who should have a say.
I work in SETI; I have used Arecibo and I’m currently looking at data gathered for me at Parkes (part of the Breakthrough Listen initiative). I know both Dan and Doug. There are some problems with Keith’s post.
By stating that: “Both the SETI and METI tribes are myopic, and somewhat inbred, by definition.” Keith reveals he doesn’t really know enough people active in both domains, nor indeed much about the topics. Strongly held views, sometimes forcefully argued, along with extensive debates with colleagues at many meetings and in journal articles, are hardly signs of either inbreeding or myopia.
And just for the record, I am on the METI Advisory Council by invitation, for the simple reason that Doug welcomed a voice that argues against sending messages (as I do), but not against sending signals (which we on Earth have done) nor against looking for signals (as I do). A reasonable presumption in all this is that our presence on Earth as “Intelligent” beings is already known to other civilisations nearby in the galaxy. There are many nuanced arguments for and against looking, sending signals, and sending messages.
(Yawn) I know a lot of people active in both tribes. I used to run the peer review panels at NASA that evaluated their research for funding back in the day. As for myopia and inbreeding – these people only talk to/argue with one another. The remaining 99% of humanity (who pays for their party) have to get their SETI updates from the SyFY channel.
Gosh – you are easily bored. In any field you will find scientists arguing their corner against different, and sometimes competing, ideas/theories/accounts… That doesn’t make them myopic or inbred. And the rest of humanity pays for that work as well (directly or indirectly). Do you have any more specific issue with S/M ETI? Or are you just trying (yawn) to be provocative?
The issue is boring because neither argument can be fortified with actual data.
It’s just opinion. Or, put in a perhaps scientific way? One’s viewpoint is a function of one’s ‘IP’, or Index of Pessimism (an inverse of IO, or Index of Optimism).
Since you are on the panel you must have a link to the meeting minutes from the meeting that approved this. I assume since this is an issue that involves the fate of all humanity the meeting minutes are available.
http://meti.org/strategic-p…
But note – there have been many decisions of which it can be more accurately stated they involve the fate of humanity; nuclear weapons and nuclear power being the most obvious. And there have been no serious debates before engaging in these activities. The novel “On the Beach” was an attempt in 1957 to make people aware of the problem of nuclear weaponry, but after the event. In addition, over-use of fossil fuels and global warming are the result of many many decisions each of which contributes to the overall threat to humanity (and other species).
Sending signals into space has been going on for decades (radar being the most obviously detectable as non-artifactual by any ETI who finds the signals). And in any case, we are probably known to exist – announcing our presence is really only useful to help others know they are not alone (which is why some of us search – not for communication but confirmation). See also https://www.nbcnews.com/mac….
Thanks!
True, but both nuclear weapons and climate change have been debated at the UN. Indeed, the US offered to place nuclear weapons under UN control in 1946, but the Soviet Union objected.
Also, although climate change may cause serious disruptions and damage it is not going to cause the extinction of humanity dispute the rantings of some environmentalists.
Yes, we do have a radio presence, but you really have to it look for it, it tends to be lost in the background noise except for some of the more powerful radar systems. But the entire purpose of this group seems to be to make other civilizations aware of our presence, regardless of the risks.
The good news is that as recent discoveries show advance civilizations even capable of SETI not to mention star travel are likely to be very very rare. So we may well be the only one in the galaxy if we are lucky.
It’s an old discussion, Keith, just coming to the fore again. The issues were hashed out decades ago.
And the answer was?
Good point. I should have framed what I meant more precisely: the issues have been discussed for decades and with no real reason to decide one way or another.
Thanks.
True, there are believers on both sides. But the one question I always ask the METI folks is if they could name a single instance when First Contact resulted in a Win-Win for both groups?
About all they are able to respond with is “This time it will be different – Trust Us!”…
You don’t get to the top of the food chain being nice and nearly all of the advances made in human history have been rooted in competition between groups, usually warfare. Indeed the Internet we communicate this on has its roots in DARPA and the desire to have a reliable post nuclear war command and control system. The scientific and economic benefits only became apparent latter.
What’s the worst that could happen? Zero chance of physical contact means every other generation advances the ‘conversation ‘, right?
You are assuming that it will always be impossible for rapid interstellar flight. But it’s foolish to think we really understand the Universe only a mere century after Albert Einstein. Things seem to make sense now, except for a few things at the fringe, but that was also true for Newton and Aristotle. But no one knows what may come about when we figure out those “puzzles”. And knowing there is another civilization that may be competition would provide some strong incentives to find if there are better options.
But consider, even at our existing level of understanding of physics if are able to develop generation ships and start moving out at just 1 percent the speed of light we could still settle the fastest part of Milky Way in waves of settlement in only 15 million years. Up that to 10 percent light speed and you drop it to 1.5 million years, about the time is took primitive humans to basically reach everywhere on Earth. So if there is an older civilization they may well have outposts much closer to Earth.
Well, on the issue of humanity’s ignorance, or naivety, you are certainly singing my song (see my response below to Dr. Woodard).
When I bring up the possibility of FTL in some far off future I am immediately challenged. And rightly so, too, if we imagine any sort of FTL being on a line representing the development of existing knowledge.
But I know this, as you do: our understanding of the Universe is paltry. I’d go this far: if there is a broad way to characterize the Universe, we don’t even know the chapter titles.
Your point about outposts is interesting.
The sheer distance makes it unlikely that an ETI could do more than just communicate, and without communicaiton detection of an ETI would be of little value. If there really is an alien species that can easily reach the Earth to wipe us out, or perhaps eat us, which based on energy considerations alone seems impractical, it’s hard to see how the presence or absence of a message would make more than a few years difference either way.
“Star Trek Discovery” posits a sort of fungus that permeates the Universe; with an appropriate system software, ships can use it to translate into any point anywhere. Preposterous? Maybe.
The series showed a brief image of this stringy substance, immediately reminding me of our current understandings about dark matter — that it is composed of “globules”, each somehow connected by vast strings of the same material, all permeating the Universe. Or something.
We know nothing about the Universe. Basic theories find it intractable. We don’t even know if current thinking and modeling is on the right track.
Forget a GUT: modern cosmology is stuck, these past thirty years or so, some discussing multi-universes (Greene, in a fascinating book), some string theory (Witten, Randall, and indeed Greene), others in different directions. All of this is good.
But progress in cosmology— the king of sciences— has been disappointing; without a firm grasp on how the Universe works we are forever in the stone age.
It seems obvious, as Dr. Woodard implies, that chemical rockets will keep us locked in our own solar system. Exploring the outer reaches with chemicals is herculean.
That’s the Universe in which we find ourselves: either figure out how to move about sans chemical reactions, or stay home.
But it’s a big, big Universe.
What if others inhabiting this grand Universe have figured it out? And leapt beyond chemical energy? What if this mysterious thing we call ‘dark matter’ or ‘dark energy’ is in fact a thing that can be harnessed?
Many things are unknown. Nothing is unknowable.
No, the usual arguments that we have been transmitting for a century do not apply here. Few of our transmissions have this much power behind them, fewer still have the narrow beam width that these folks are using. Your typical radio station will wash into the noise background in under a light-year, this signal can punch through that – and it was designed to. This group’s signal is also carefully designed to be detected – they send it and repeat it specifically so that an alien intelligence would be able to notice it, lock on its position and verify it. Finally, they are not sending the signal to a random location, but to a specific planet in the potential life-bearing zone of its star.
None of us knows if there is anyone there to hear this signal. So, logically, there is some unknowable chance that there is. And if the aliens are there, we have *no* information on their intentions nor their technology. Thus there can be no logical argument that they are either benign vs. dangerous, nor stuck at home vs. space-faring. People make silly guesses on this topic a lot, but, in truth, we simply don’t know.
Keith’s last statement is correct – this is something that should be up to all of us as a species. I, for one, signed no document saying that this arrogant METI group could speak for me, or my children, or the entire Earth. I never signed a document saying they were authorized to take a risk, however small, that might wipe out our civilization. Did any of you?
So… assuming they are like us, the aliens are also sitting around deciding never to send a signal for fear we will come and eat them. So neither species will ever know the other exists.
You make that sound like that would be bad. Do you think it would have been bad if the indigenous Americans, Pacific Islanders or Australians had never learned that Europeans existed?
No.
How many genuinely “first” contacts have we seen? There was no real “first” contact between Europe and China, since trade (at a low but non-zero level) had been going on between as far back as republican Rome. Gunpowder got from China to Europe well before European warships made the trip in the opposite direction. I’m not saying I disagree with your point; I just don’t think we have enough experience/examples to draw definite conclusions.
Yeah, there’s a tendency to use historical invasions as a proxy for “first contact” failures.
Some discussion about tribes in South America have raged among anthropologists in recent decades (including some shady research). Some have pointed out that even if Amazon tribes haven’t met more modern peoples, they have certainly observed jet aircraft far overhead.
If the indigenous tribes learned to communicate they would have had the option of using wheels and antibiotics, and ultimately modern technology and political systems with which they could have asserted their independence. We are better off knowing what is out there, and we are better off knowing sooner rather than later.
Except for the ones that will die from diseases they have no immunity to, or from the cultural shock. Wheels are only of value if you have lots of stuff to carry, which is not the culture of hunter and gathers.
As you point out, the low power used in METI (with a few marginal and Russian outliers) is laughable. This is a tempest in a teapot.
It sure is fun, though!
I don’t think these METI folks have read Greg Bear’s “The Forge of God” and “Anvil of Stars”.
Or Lovecraft.
I am just trying to imagine what the actual risk level is. I would think that it would be considered extremely unlikely that intelligent life at the technical level that we are talking about exists even within 1,000 light years of Earth. Can I quantify that? No of course not no one can. But the usual arguments for ETI is that there are billions of solar systems in our galaxy and billions of galaxies, and thus the belief by many that at least some of those quadrillions of star systems may harbor intelligent life. But 99.999% of those star systems are millions and billions of light years away. The odds just seem astronomical in my opinion that alien intelligent life exists anywhere near us.
But even if against all odds there happens to be a highly advanced, ill-tempered civilization let’s say as close as 1,000 light years away, and they have the capability of travelling at say half the speed of light, that means the soonest they will be here to conquer or destroy us after receiving our message is 3,000 years from now.
Okay I realize we have to think about future generations, but the odds just seem overwhelmingly low that we will stir up the proverbial hornet’s nest this close to Earth. As far as I am concerned we could send a message that says “Yo momma” and nothing would happen. But I can understand that people don’t want to take a chance without at least thinking about it.
That math doesn’t really work. If you want to know your chances of seeing, say, a zebra, your answer will be different if you are in Kenya vs averaging over the entire world. Life clusters in the environments where it does best. It is reasonable that the Earth is in the exact right place for intelligent life to develop – farther in toward the galactic center and supernovas are too common, farther out and the heavy elements are less likely to be present. Based on this thinking, the most likely place to find our alien zebra actually is a nearby star.
We all have feelings one way or the other on the odds of having neighbors, but we don’t yet know enough to calculate the odds better than saying it is 0% to 100%. We don’t know their dispositions. We don’t know how fast they could get here.
Given that, why would you or anyone want these METI folks to risk your life, your home, everything you’ve ever known? Even if the risk does turn out to be small, the cost may be enormous.
I didn’t state any numbers for odds so I’m not sure what math of mine you are referring to that doesn’t work. I agree with your 0% – 100% comment, in fact I thought I was saying the same thing when I said “Can I quantify that? No of course not no one can.”
As to why I would want the METI folks to risk my life, my home, everything I’ve ever known, well if it’s all about me I have nothing to worry about, unless I think that some dastardly aliens happen to be living just a few tens of light years away and also have the ability to travel faster than the speed of light to come kill me. Without doing any math I have just formed my own opinion that the odds of that are too low to even worry about. But as I said we should think of the generations several hundred or even thousands of years from now, and although even from that viewpoint I am not concerned about METI, I agree that everyone should have some say in this.
Rather than base this on whether or not we’ve already broadcast enough to make this a moot point, what about considering the aliens’ technology? Without some sort of warp drive or (if they are very close) reasonably effective, relativistic spacecraft, they can’t get here (or could only send a fairly harmless probe, and even then, it would take a long time to get here.) If they do have that sort of technology, and they are close enough for radio contact, odds are they’d be here already. There aren’t all that many stars within 100 light years or so.
Any method of interstellar travel works better as a planet killer, because you don’t have to waste fuel slowing down. And it requires no more technology than that “harmless probe”. Meaningful travel, otoh, is much more complex and demanding.
I take your point, but if we are speculating: perhaps objects can be ‘translated’ from A to B with no change in velocity.
Who knows?
Sure, we can suppose “magic”, but FCrary was suggesting that hostile response is unlikely because of limitations on technology. Surely “magic” has weapons applications?
(Even with no more information than you’ve provided, I can already think of a way to weaponise your Translation Drive.)
You are so right- it IS magic, in the sense meant by Sir Arthur.
We either imagine something ‘magical’ in the future enabling deep space travel or we accept that the solar system is our home, never to be seen in a rear view mirror.
To imagine anything less we are just cheating ourselves.
Actually, that was only half of my point. On the one hand, if they are not capable of very advanced interstellar travel (or magic), they can’t get here and cause harm. So deliberate efforts to communicate are harmless. If, on the other hand, they do have very advanced interstellar travel (or magic), they will probably find us in the course of their own exploration and expansion. In that case, broadcasting or staying silent doesn’t make a difference. The potential threat from broadcasting requires a intermediate (and possibly narrow) range of capability.
However, in that case, such deliberate communication should be common enough to be obvious at our level of technology. We should hear First Contact messages from the nearest neighbours who are of the chatty type.
We don’t, therefore the combination of “communication AND harmless” are excluded.
Which one is excluded is still unknown. But sensible precaution suggests delaying deliberately making ourselves louder and more obvious until we’ve had a chance to put some numbers on the number and variety of life-bearing worlds in our neighbourhood.
If you send a message out into the ocean to say a whale,(1) would it reply to you,and (2) would if it did reply would you know what it is saying?
We cannot communicate with other “intelligent” creatures here on earth why should we think we can communicate with beings on a planet 12 light years away?
We will be waiting 25 years to see if our efforts to communicate have been successful.
Seems pretty pointless to me.
That is silly. We are already having this dispute within our single civilisation. It makes no sense that every single civilisation chose not to transmit, even after observing neighbouring life-bearing planets for millions of years. (Unless they have a Very Good Reason.)
All the anti-METI scientists are saying is that:
A) We don’t know enough to transmit into the darkness. It doesn’t mean that we won’t know enough in the future. We’ve only just barely discovered exo-planets. We haven’t checked the most obvious places in the solar system for non-Earth life yet. We a just starting. Give us some time to figure out what the universe is like. Are we really so pathetically childish that the alien contact has to be in our lifetimes? Lets have the argument when we’re at least got a good handle on the percentage of life-bearing worlds out there and a map of those in our neighbourhood. Let’s at least transmit to, not at.
B) It’s very quiet out there. “Too quiet.” Given the number of civilisations that must be out there for METI to be worthwhile, it’s incredible that widespread communication isn’t common. Absent that, either they are rare enough that METI is pointless, or they have a Very Good Reason for remaining quiet. And maybe we should respect that until we know more.
The reasoning behind (B) is that…
C) Non-communicative civilisations play no role in the culture of communication in the galaxy. You can’t stop chatty civilisations from talking to each other by sitting in silence. That infamous island south of India with the tribe that tries to kill everyone who approaches (Sentinelese), they can’t prevent other peoples from contacting each other. If even a small percentage of chatty types risk opening contact (even if they wait for a few thousand, a few million years until they can see who they are contacting), it will spawn a culture of communication across the galaxy within tens of millions of years, because every younger neighbouring civilisation they contact (even ones that might otherwise not risk transmission) will assume that the multiple signals from multiple star-systems represent the galactic norm. We would have. Eventually the dominant culture that every radio-civilisation emerges into is one of active communication.
The only way for a non-communicative civilisation can prevent tens of millions of other civilisations from communicating, the only way they can create a culture of silence across the galaxy, is by actively silencing the chatty types.
And here were are, broadcasting merrily away, debating turning up the volume even louder.
D) METI advocates like to go on about the benefits of contacting the older wiser civilisations, what great knowledge could they impart, what wisdom. And yet they wilfully ignore the only advice the aliens have ever given to us, every day since we turned on the first radio telescope.
“Shhhhhhhhhh…”
Is that necessarily the case? When serious SETI efforts started, in the 1960s, the past half-century had seen a constant and rapidly growth in terrestrial radio emissions. It was reasonable to say, “of they are anything like us, we should be able to detect them.” But, based on trends in the past few decades, I’m not sure if that still makes sense.
While communications and transmission of data across the globe has continued to increase, how much is in the form of high-power, isotropic broadcasts? I think most of the growth has been in low-power, short-range isotropic broadcasts (cell phones and wireless) and either landlines or directional transmission (satellite dish or microwave relays.) What we do broadcast may be less recognizable. Lossless data compression inherently involved removing the redundancies and patterns which make a signal more easily identifiable as artificial. High data rates mean higher bandwidth (literally), so the transmitted power is spread over a wider range of frequencies.
In addition, the frequencies we have used have changed dramatically since the early twentieth century. NASA has begun developing laser communications for planetary missions.
What if the first half of the twentieth century was just an awkward and brief phase in our technology development? What if that’s also true of extraterrestrial civilizations? What if they’ve all advanced to using short-range wireless, fiberoptic cable for between the wireless hubs, and massively high data rate with advanced compression software? Would we actually expect to detect something like that?
Excellent points. It’s unlikely an advanced civilization would waste energy radiating, and if we are afraid to transmit we can reasonably assume they will be as well. If neither civilization is willing to announce themselves, we are likely to miss out on a lot of otherwise inaccessible information that would give us time, probably centuries, to prepare for any actual physical contact.
Long Post Warning.
If METI makes any sense, there must be another civilisation near enough to contact. Given the… impatient (IMO childish) nature of METI advocates, obviously they want a reply in their lifetimes. So that limits you to no more that 40 lightyears (and preferably closer).
Merely assuming we aren’t unique and aren’t uniquely close to the only other living civilisation in the galaxy, that gives you a reasonable estimate of the density of civilisations at any given time.
The main star holding part of the galaxy is around 100,000 LY across and 1000 LY thick. Assuming roughly one civilisations every 40 light years, then arbitrarily assuming that 90% of the galaxy can’t support life (too many super-nova, too little heavy elements, etc), that leaves 150 million civilisations currently able to pick up METI-type messages from up to 40 lightyears away.
It’s hard to estimate how long the galaxy has been capable of giving rise to technological civilisations, but the ability to form Earth-like planets clearly goes back 5 billion years. Even being conservative, the galaxy should have hosted radio-civilisations for half a billion to 2-3 billion years. So hundreds of millions of civilisations, probably growing in number over time, for hundreds of millions to billions of years.
And none of them contacted each other?
Because if they did, then that contact is what they know about neighbouring civilisations. Think about it, only those who communicate find out about each other, so their idea of “normal” is those chatty types — even if 90% of civilisations don’t ever answer, the 10% of chatters are the ones who create the culture that every new civilisation emerges into.
[Although if 90% of radio-civilisations don’t answer, then the estimate for the number of civilisation for METI to be worthwhile must increase ten-fold (ie, ten civilisations within 40 lightyears, in order for one to answer.) Remember, these aren’t my numbers, I’m using METI’s assumption that there must be one civilisation with reasonable distance that will detect and respond to radio contact. Everything else follows from that.]
If it didn’t happen, and it didn’t, then something stopped it.
Either life or intelligence isn’t common (and METI is harmless but pointless)
or
something weird is happening.
Ben Bova in his novel “New Earth” ( spoiler alert) proposed that instead of coming to Earth they establish an Earth like planet in s nearby Solar System and wait for humans to reach it by s starship. Then a special group makes contact with an educated small team of scientists open to the idea too far away to immediately communicate with Earth. The aliens also impose a communication blackout until it’s determined humans are able to handle it.
As part of the strategy the Earth itself is strictly quarantined including blocking of any radio messages leaking from Intelligent civilizations. It is the best idea I have seen yet on how to limit risk from first contact. If the humans are not able to handle it you just block their transmission and use them to study how to communicate better to the next group that arrives.
Earth had life almost since it became habitable, but civilization has appeared only now when over 90% of the habitable period has elapsed, to end within perhaps 100 million years due to increasing solar luminosity. This suggests that civilization may be rare, as does the absence of visible indications of ETI. Science fiction aside, the energy requirements for interstellar travel make it extremely difficult while communication is relatively easy. If we are alone, there is nothing to lose. If we are not alone, there is much to gain from the exchange of knowledge.
Then METI is worthless. My argument was based on using METI’s assumption that there are radio-civilisations near enough to hear and respond within a reasonable time.
And that applies to Them as well. All the civilisations since the galaxy was capable of creating it. If the galaxy isn’t awash with communicating civilisations by now, there must be a reason why they don’t. We should respect that until we understand it.
What’s the point of seeking their wisdom if we ignore their first lesson?
You are off by several orders of magnitude. If life started 4 billion years ago and civilization 10,000 years ago then its more like .00025 of 1 percent of the Earth’s life.
Even complex life didn’t emerge until only the last 12 percent of the Earth’s history. If you use that as a measure than civilization only emerged in the last .002 of 1 percent of the history of complex life on Earth.
It appears that extreme stability is one of the conditions required for civilization to exist.
This subject is a personal bug, so I’ll tend to go on a bit. Long Post Warning.
As I said, silent civilisations play no major role in the radio culture of the galaxy. Only those who communicate. Therefore the audible culture of any galaxy should be that of communication.
And it’s reasonable to suppose that many or most civilisations that reach radio-level go through a similar burst of using more and more radio (and radar), before developing better radio technology, before moving beyond radio.
Which means that older neighbouring civilisations can detect the development of younger civilisations. A reasonable percentage of civilisations will be curious about the universe and have radio astronomy, and a reasonable percentage of older civilisations will have radio astronomy that’s more advanced than ours.
If some of those older civilisations are part of a culture of communication, then they (at least some of them) will actively seek out contact with the newbie, because that’s “normal” and “expected” for all the civilisations they’ve ever spoken to, as well as their own history. You invent radar and radio and start broadcasting, a few decades later you develop radio astronomy, by which time the nearest older civilisations have detected you and sent Generic First Contact Package, based on half a billion years of collective galactic knowledge. (Possibly several have sent it from different directions, because it takes time for news of your “arrival” to filter out across the galactic network, and a certain percentage of civilisations will compete to be First.)
Given that we are already detecting exo-planets, it’s likely that they’ll have a reasonable idea which neighbouring planets are suitable for life, which have bio-markers in their surface or atmospheric spectra, maybe even detect pollution, land-use changes, and/or city lights.
And given the necessary density of civilisations in the galaxy for METI to make sense, random distribution will put some of them much closer to each other. Which means that younger civilisations will (eventually) have the ability to detect their older neighbours, if they are close enough. At some point, someone is going to say “Hello” (or “Stay Away”). At that point, at least some will pick up the ball and run with it.
The only assumptions I’m making is that: A) if METI is worthwhile, there must be a nearby civilisation. And B) we aren’t unique. (Therefore, we aren’t located next to the only other radio-civilisation in the galaxy, nor are we the only civilisation in the entire galaxy’s history that likes communication, nor are we in the galaxy’s first batch of civilisations. We don’t have to be average, hell, we can be the right-most point on the bell-curve, as long as there are other right-side points on the curve, the reasoning still holds.)
Hence, it’s not about us and one Other. It’s about what culture would have developed across the galaxy in the last half billion to several billion years.
Silence is a weird outcome. Silence is a suspicious outcome. We should be concerned about Silence, we should be cautious about becoming deliberately louder. Either radio-civilisations are so rare that METI is stupid and pointless, or something is silencing radio-civilisations and METI is stupid and dangerous.
And even if I’m wrong, I’m not saying be silent forever. Just until we understand who/what we are broadcasting to. Eventually we will be able to detect a bunch of neighbouring civilisations, even if they are radio silent. If so, we can have this debate again.
It could be that beyond a certain distance random EMR cannot be detected by even the most advanced civilization. Just as it’s possible that even the most advanced civilization cannot exceed the speed of light (separate topic). We like to think that given enough time there are no limits to what can be done, but it’s possible that even with unlimited time there are unbreachable limits.
Thus communication beyond a certain distance may always require high power, focused energy, directed at a particular star system. Similar to what METI is already doing, but at a much higher power and precision than we currently have, or perhaps can even imagine right now. And it also might require extremely advanced listening systems on the other end to hear even those powerful, focused messages.
Thus only civilizations that have reached that level of technology can communicate with each other, or for that matter even know that the other exists. In my hypothetical scenario, even the most advanced civilization cannot detect the presence of another civilization beyond a certain distance, unless the other civilization sends a high power communication directed at their star system.
Even if this is the case that communication over large distances must be directed, communication between multiple civilizations would still be possible by repeating the messages. For example let’s say civilizations 1, 2 and 3 (C1, C2, C3) communicate with each other as a group. If C1 sends a message to the group they have to aim their antenna (or laser beam or whatever) at C2 and send the message, then they have to aim it at C3 and send the identical message. This method would have no limitation as far as the number of participants other than distance. But even then, if say C1 is too far away from C9 to communicate directly, but both C1 and C9 are within range of C5, then C5 can relay messages between C1 and C9.
So there could be all kinds of chatter going on and we just don’t know about it because we aren’t on the “party line”. Meanwhile they don’t know we are here because our pipsqueak signals aren’t detectable even with their sophisticated receivers. However every 1,000 years or so the civilizations nearest us have been aiming messages at us, as they do with all of the “silent” star systems in range of their powerful beams, but so far we don’t have the technology to hear it, much less respond, so they shrug their shoulders (or whatever they have) and move on, and try again in another 1,000 years.
Then METI is pointless.
As I said, the only reasonable scenarios are that METI is pointless or METI is dangerous. The only (less reasonable) scenarios where METI makes sense are so weirdly bespoke and arbitrary, that it makes sense to exercise caution until we know more.
But regarding your scenario for its own sake (because this topic always interests me): We have a reasonable understanding of the behaviour of EMR from natural sources. In order for artificial EMR to act differently, there would have to be a fundamentally new phenomenon, currently unknown to physics.
If there’s not some kind of magic effect that preferentially blocks artificial signals, then any civilisations should be able to detect any neighbour: Are you familiar with gravitational lenses? Essentially you launch a telescope in the opposite direction to the target star system, and when it gets beyond a certain distance (around 530AU, but the further the better), the telescope uses the Sun’s gravitational well as its primary lens. It magnifies any object to the point that it is as if the target is inside our own solar system at the Sun/Telescope distance (ie, 600AU or so). It’s expensive and difficult, compared to near Earth telescopes, but it’s vastly cheaper than sending an interstellar probe. (4 lightyears is over 250,000 AU.)
A gravity lens telescope (or rather one for each target), means we can image the surface of the target planet. We should be able to detect the spectrum of land/sea/ice and “other” (such as alien equivalents of forests, grassland, plankton blooms, etc). And with enough examples of “other” from different systems, we’ll draw conclusions about the nature of life. We’ll also be able to “see” the presence of oxygen in their atmospheres. That will give us examples of definitely life-bearing planets. With a statistical sampling (on top of the larger amount of exo-planet data at a lower resolution from more conventional, but cheaper, telescopes) we’ll have a really good estimate for the number of life-bearing worlds in the galaxy (how quickly life forms around young stars, what types of stars/planets, what distance from the galactic centre, etc etc.)
If the telescope at the gravity lens is large enough, you might be able to pick up light variations on the surface on the night side of the planet/moon allowing you to see city lights.
A gravity lens will also focus radio, so a radio telescope at that distance will pick up even low power incidental radio/radar. The equivalent of cell-phone towers, or surface-to-satellite relays. Even if we can’t interpret the signals (can’t even separate one from another), we can detect it. Just from the variations in overall signal strength over the rotation of the planet will allow us to learn a lot about their civilisation.
Not least of which is, do they have satellites, do they have colonies, potentially do they have their own gravity lens telescopes. Signals from any GLT pointed at us, back to their own world will also be focused by their star towards us, then refocused by our sun onto our GLT receivers. Ie, if they are watching us, we can “hear” it, once we are watching them. (And vice versa.) Again, we might not understand the data-format, but we’ll detect the signal itself. (Which is another reason we can afford to wait until we understand more about life in the galaxy before we intentionally send more METI signals. GLTs make it so much easier.)
Obviously, that effect can be used intentionally. Such focusing drastically reduces the amount of power required for signalling. (Still high, but millions of times lower than without the gravitation lenses.) That allows relatively low energy interstellar communication. That means that, over the hundreds of millions to billions of years of civilisation in the galaxy, those civilisations interested in communication with their neighbours will come to dominate the culture of the galaxy.
And while transmitting a signal from a GLT to a non-GLT civilisation is harder than GLT-to-GLT, it’s not much harder than transmitting from the your own GLT back to your own inner planets. Ie, if our neighbouring civilisations were broadcasting to us via their GLTs, it would be at the same power level of a transmitter at around 600AU from Earth. Not an unreasonable level for them to “waste”, given that they already have one GLT for each target star anyway. So the only issue is culture, do they care? And as I said, the galaxy’s culture should be “communicate with everyone, early and often”, even if 90% of radio-civilisations don’t participate. So it’s doubtful that the “chatters” would broadcast to a target civilisation only once every millennia. Nor would it be just one sender.
That’s why I say that the Silence is weird.
And weird is suspicious. And suspicious should lead us to be cautious until we know more.
In terms of METI, again it means we aren’t capable of signalling our neighbours. So METI is pointless.
And so in terms of the precautionary principle, can we not wait? Must contact be in our lifetimes? (Or in some cases, just the transmission. Some METI advocates don’t seem to care about the answer, they just want to be the ones who send the signal. “Look at me! I’m important! Everyone pay attention to me!”.)
I knew about gravity telescopes but I didn’t realize that the capability could in theory be so great, for some reason I assumed that it becomes distorted at a certain magnification. However even if the surface of a planet can be imaged, I would think there could be a practical limit to how far this will work. For example is it possible to image the surface of a planet in another galaxy? If so, only nearby galaxies, or even the furthest away galaxies? Not that we necessarily need to look that far, but again it depends on where the nearest neighbors are which we don’t know. If ETI is rare and the nearest civilization is in another galaxy and detection doesn’t work that far then it is of no help.
I realize that theoretically there may be no limits, but there could be practical limits, at least as far as any civilization has advanced so far. Although for some reason the idea of practical limits is often dismissed, the rationale being that we have no reason to put a limit on what advanced civilizations are capable of. Well it’s not setting limits, it’s just considering that there could be practical limits hindering other civilizations. For example someone may calculate that it’s possible to travel by wormhole but they calculate that it requires the amount of energy equivalent to a quasar. One group will say okay so it’s possible. The other group (including me) will be somewhat pessimistic that any civilization no matter how advanced will be able to harness the energy equivalent of a quasar and use it to propel themselves through space. I don’t rule it out, but that’s the direction that I lean, whereas others will lean towards believing that someone out there will figure out how to do it if they haven’t already. Now maybe FTL is possible without that energy requirement, but we don’t know and I’m just saying that theoretical and practical may not be the same thing even for advanced civilizations. Considering that even the oldest and most advanced civilizations are not where they will be in say another million years.
The gravity telescope would still be a form of directed communication (and receiving) which is what I surmised might be necessary for communication beyond a certain distance, what I referred to as the “party line”. Which could explain the silence. The signals are out there, but not directed at us, at least not most of them. Some occasional signals may be directed towards us, either from someone just shooting blind at a star system as we are doing with METI, or maybe someone has detected us with a gravity telescope and is attempting to contact us, but we don’t have the required equipment to hear the signal. Another possibility is that they are so far away that they are still looking at light from pre-civilization Earth. Or maybe they have already sent a message but it won’t arrive for another several hundred years.
I mentioned the 1,000 year example, just imagining that it takes a certain amount of effort to send these signals, and with millions or maybe billions of star systems to aim at, for a silent system that they so far have not detected intelligence, they figure 1,000 years is a good interval to “ping” a star system as it could take millions of years before intelligence develops there, if ever.
All of these potential practical limits combines with the other unknown which is how far away is the nearest civilization that we can communicate with. We are hoping that either there are no limits, or if there are that civilizations exist within range of those limits. Or for those who feel safer remaining isolated (I’m not saying you are) they hope for the opposite, that no advanced civilizations exist close enough to either detect us or destroy us.
Re: Gravity lens telescopes
Normal limits for a telescope based on light gathering size. The size just happens to be the star’s gravity well.
In practice, you’ve not only got interstellar and intergalactic dust/gas acting to blur things, but also the light is being randomly deflected by every gravity source along its path. I suspect the latter causes more distortion than anything else.
I don’t know the theoretical limits at surface-resolution. I’ve been told it should work for nearby exo-planets out to many tens of lightyears, but how far out you can get I’m not sure. However, with clear data from nearby exo-planets, you can work out the spectral signature of known feature types, allowing you to interpret lower-grade data from more distant exo-planets.
[I should point out, the telescope only sees an Einstein ring. But that distortion is mathematically predictable, and hence reversible, especially if you can “scan” by moving the telescope back and forth across the focal line. You aren’t taking Hubble-style “pictures”, but you can computer extrapolate a fair amount of detail.]
If we were contacted, from multiple directions, right from the start of radio astronomy, then I wouldn’t be bothered. It’s the Silence that concerns me.
If it’s just because intelligent life is rare, then so be it. But if intelligent life is common but silent, something weird is going on. And I don’t trust my species’ existence to the kind of idiots who fill the ranks of METI.
However, a signal sent from a gravity-lens telescope will be focused by their own sun. So when it arrives, the signal will be the equivalent of one sent from 600AU in our own solar system. For a signal as weak as the Voyager probes (23W at 100AU, which we can obviously detect), would require a 1kW transmitter. (Which they can buy off Ali Baba for around $2000.) It’s easier to have another gravity-lens at the receiver, but it’s not necessary.
So for any reasonable density of radio-civilisations, the issue isn’t “can they”, it’s “would they”. And if the party-line exists at all, then it means that a culture of communication exists in the galaxy. Over time, no matter how few civilisations were non-isolationist in the beginning, the culture will become more and more chatty; because only the non-isolationists make contact with new civilisations, and those later civilisations don’t know anything different.
Hence the party-line can’t explain the silence, because the party-line would never exist unless someone started making First Contact with new civilisations.
[Obviously, if the civilisations are 1000’s of lightyears apart, nothing less than a network of GLTs would be required for communication. But then it’s hard to see how it would get started.
However, as I said, it’s not the possibility that intelligent life is rare that bothers me.]
Put me in agreement with B). The silence is unnerving to contemplate, and I’d prefer not to blast out our presence into interstellar space until we occupy a couple more worlds (and maybe more than one solar system).