METI: A Longer-Term Perspective

While the debate over sending messages to nearby stars continues, it’s interesting to probe the issue quantitatively, as Jim Benford did on Friday, asking whether recent attempts at METI could be heard at destination. The subject prompts Keith Cooper, now editor at Astrobiology Magazine, to examine ways of reaching consensus on a matter that raises strong opinions whenever it is raised. If these messages are unlikely to be heard, is there a technological window here that we can use to find consensus through continuing research? Keith is well-known to Centauri Dreams readers, having engaged with me in a series of dialogues over the years on various interstellar topics. Look for a new dialogue early in 2018.

By Keith Cooper

On Friday, Jim Benford’s brilliant essay showed how the latest METI signal will not even be heard at its target destination, the planet GJ 273b, which is only 12.4 light years away. Whichever side of the debate you fall on, messages that can’t be detected at their target are a waste of resources. In light of this, METI activists may want to rethink their strategy.

(As an aside, this highlights why civilisations might be hesitant about transmitting without knowing that there is going to be someone listening; the resources, both in terms of energy and time, that are required to do the job properly are huge and you can imagine that frugal civilisations might not bother, or only do so sporadically.)

Image: Keith Cooper (left) with Jim Benford at a recent meeting in London.

There’s a window of opportunity here for both sides of the argument to come together while METI is effectively curtailed by a lack of access to sufficiently powerful transmitters (which, besides Arecibo and military radar, are thin on the ground). I’m not thinking of spending this time endlessly debating the issues. The SETI Institute’s Seth Shostak has suggested that the conclusion of any symposia called to discuss the risks of METI will always be a foregone one against transmitting (which may explain why METI activists are so keen to avoid discussion), because since we have no understanding of how ET will behave, there will always be a risk.

I think he’s probably right, but then I have to ask myself, is that the kind of civilisation that I want us to be, forever shackled by fear? I look at some of the names involved in METI International and I am honestly surprised. So many of those listed on their website are smart people whom I admire greatly, people such as Jerome Berkow, Steven Dick, Alan Penny, Paul Davies, George Dvorsky, Chris Impey, James Kasting, Lori Marino and on and on. If so many smart people whose opinion I respect are in favour of deliberately seeking contact, who am I, a mere journalist, to disagree?

You know something? I don’t disagree. Neither, I’m willing to bet, do Jim Benford, David Brin or any of the other vocal critics of METI. We don’t want to hide from contact – ultimately that’s the whole point of doing SETI. The difference comes in that we don’t think sending out signals left, right and centre, with no thought put into who we are trying to contact and what we’re trying to say, is the responsible way to announce ourselves on the galactic stage.

Scouting the Galaxy

I think there’s an alternative way. I will warn you now, it will require patience, but if we are to get to the end of this century in at least as good a shape as when we entered it, then we will need to be patient and implement long-term plans to combat climate change, over-population, poverty and so on. Why should our attempts to make contact, given the vast distances and timescales involved, be an exception?

Our current situation is that we don’t know what is out there. So before transmitting, let’s perform some reconnaissance. The advent of the Breakthrough Starshot project, which intends to fire laser beams to accelerate thousands of tiny ‘StarChip’ nano-probes to a fifth of the speed of light towards Alpha Centauri, makes such reconnaissance eminently more probable. If all goes well, the first StarChips could be launched by the middle of this century. In just over 20 years they would reach their destination, but why stop at sending these probes to Alpha Centauri? Travelling at 0.2c, they could reach GJ 273b within 62 years. The probes could survey the system for signs of life or even technology (perhaps in the form of city lights, atmospheric pollution or artificial structures), and report back.

In the intervening years our largest telescopes will be able to perform their own kind of reconnaissance from a distance. The James Webb Space Telescope, the European Extremely Large Telescope and the Thirty Meter Telescope will all be able to perform spectroscopic analysis of the atmospheres of the nearest potentially habitable worlds, searching for biosignatures including gases that are in chemical disequilibrium with their environment, such as oxygen, methane and others. The latter two ground-based telescopes might even be able to directly image these planets. The Square Kilometre Array and the FAST telescope in China will listen intently for SETI signals. We will learn more about our own Solar System, about how the conditions to support life came about on Earth, and whether life exists elsewhere in our Solar System, be it on Mars, Europa or Enceladus. We will come to a much better understanding of life in the Universe and the odds on finding such life elsewhere.

The point is, over the next century we will be in a far better position to say whether there is life out there in any nearby planetary systems. In fact, I’ll go one step further and make a bet that, if life exists on a planet anywhere within 50 light years of here, we will have found it by 2100. Our probes will be sent to investigate surreptitiously, likely too small to be detected by any civilisation out there. Once we’ve learned of them, and about them, we will be in a far better position to deliberately open a channel of communication with them, with first contact performed by trained diplomats and scientists. This would be in stark contrast to secretly sending out a message and not making that information public for a month. A group that claims to speak for Earth but which does so in secret isn’t speaking for anybody but themselves.

Patience in good measure

As I write this, I’m reminded of Milan ?irkovi?’s hypothesis of energy-optimised ‘city states’ in his ‘Against the Empire’ paper, wherein civilisations recognise the huge expense of transmitting signals or launching crewed interstellar spaceflight, and instead send out scouts in the form of robotic probes to explore the Galaxy and seek out life. Indeed, interstellar probes have long been part of the fabric of SETI, going back to Ronald Bracewell in the 1960s and the novels of Fred Saberhagen (although his berserkers aren’t quite what I have in mind!).

If, after launching our probes and scrutinising nearby planets with our telescopes, we find intelligent life, and we get an idea of what they’re about, then we can consider opening hailing frequencies with them. This approach lacks the immediate satisfaction of sending messages now, and quite possibly none of us will be alive when we find such life, but in the long-term – and make no mistake, contact with another civilisation will have repercussions, good or bad, that run into the long term – it seems the most sensible way to go about making contact.

It does require patience and perseverance to see the plan through to its end, but METI activists often deny that they are being impatient when they rush to beam their messages out into space. Seeing as their messages are not currently powerful enough to be heard by anyone anyway, this is their chance to prove that they are not acting out of impatience by joining a century-long plan to make contact by initially performing the required reconnaissance of our neighbourhood, taking the time to learn a little more about what’s out there. While we are performing our reconnaissance, we will be able to take the time to really figure out how we want to communicate in a responsible fashion and prepare society for the potential of contact.

The SETI 2020 report called for cultural maturity before we make any big decisions about contact. By finding the patience to maintain a century-long project of exploration of nearby planetary systems, maybe we can reach the required level of maturity.

So I’m throwing down the gauntlet. To those whose aim is to find life in the Universe, I say, come together and develop a long-term plan towards achieving this aim. To the METI activists, I say, hold off on your wasteful transmissions and join us. It may take a while; we may not be alive to see its completion, but once our project has found intelligent life, once we’ve performed surveillance to understand that life better and the associated risks of contact, then let’s transmit together, as a united world. The risks will be far less and the potential benefits or working together far, far greater.


METI: A Response to Steven Johnson

Yesterday’s post dwelt on an article by Steven Johnson in the New York Times Magazine that looked at the issue of broadcasting directed messages to the stars. The article attempted a balanced look, contrasting the goals of METI-oriented researchers like Douglas Vakoch with the concerns of METI opponents like David Brin, and fleshing out the issues through conversations with Frank Drake and anthropologist Kathryn Denning. Johnson’s treatment of the issue prompted a response from a number of METI critics, as seen below. The authors, all of them prominent in SETI/METI issues for many years, are listed at the end of the text.

We thank Steven Johnson for his thoughtful New York Times Magazine article, which makes it clear that there are two sides to the METI issue. We applaud his idea that humankind needs a mechanism for decision-making on long-term issues that could threaten our future.

As Johnson implies, deliberately calling ourselves to the attention of a technological civilization more advanced than ours is one of those issues. What we do now could affect our descendants.

As Johnson asks, who decides? Without an agreed approach, the decision to transmit might be made by whoever has a sufficiently powerful transmitter.

Astronomers have given us an additional reason for addressing this question: the discovery of thousands of planets in orbit around other stars, increasing the probability that life and intelligence have evolved elsewhere in our galaxy.

METI is not scientific exploration. It is an attempt to provoke a reaction from an alien civilization whose capabilities and intentions are not known to us.

The most likely motivation for alien intervention is not a wish to exploit Earth’s territory or resources, but the potential threat posed by a new space-faring civilization — us. Scientists and engineers already are designing Humankind’s first unmanned interstellar probes. Some might be visiting nearby stars less than a century from now.

Image: Taken by the Advanced Camera for Surveys on the Hubble Space Telescope, this image shows the core of the great globular cluster Messier 13, to which a message was beamed in 1974. Credit: ESA/Hubble and NASA.

Though altruism may be a noble goal, human history suggests that it rarely extends beyond one’s own species. We have not been very altruistic toward dolphins, whales, or chimpanzees.

What mechanism can we devise for what Johnson calls global oversight of METI? In the 1970s conferences at Asilomar assessed dangers from the then theoretical notion of genetic engineering. The resulting compromises improved laboratory safety while allowing continued research in this field under an agreed set of rules.

In the 1980s, some of us proposed a first step toward agreed rules through the document known informally as the First SETI Protocol, which calls for consultations before responding to a detected alien signal. (That protocol has been endorsed by most SETI researchers, but has not been adopted by government agencies.) An attempt to gain consensus on a second protocol calling for consultations before the transmission of powerful, human-initiated signals foundered on a basic disagreement that is mirrored in today’s METI debate.

Seventeen years ago, the International Academy of Astronautics presented a proposal to the United Nations for an international decision-making process for sending such communications. The U.N. noted the report and filed it.

Plans to send powerful targeted messages to nearby solar systems have brought this issue back to our attention. The underlying issue has not changed. As renowned Chinese science fiction writer Cixin Liu wrote, “I’ve always felt that extraterrestrial contact will be the greatest source of uncertainty for humanity’s future.” Let’s address that issue as rationally as we can.

Gregory Benford, astrophysicist and science fiction author

James Benford, radio astronomer

David Brin, astrophysicist and science fiction author

Catharine A. Conley, NASA Planetary Protection Officer

John Gertz, former chairman of the SETI Institute

Peter W. Madlem, former board member of the SETI Institute

Michael Michaud, former diplomat, author

John Rummel, former Director, NASA Planetary Protection Office

Dan Werthimer, radio astronomer


Wrestling with METI

If we were to send a message to an extraterrestrial civilization and make contact, should we assume it would be significantly more advanced than us? The odds say yes, and the thinking goes like this: We are young enough that we have only been using radio for a century or so. How likely is it that we would reach a civilization that has been using such technologies for an even shorter period of time? As assumptions go, this one seems sensible enough.

But let’s follow it up. In an interesting piece in the New York Times Magazine, Steven Johnson makes the case this way: Given the age of the universe, almost 14 billion years, that means it would have taken 13,999,999,900 years before radio communications became a factor here on Earth. Now let’s imagine a civilization that deviates from our own timeline of development by just one tenth of one percent. If they are more advanced than us, they will have been using technologies like radio and its successors for 14 million years.

Assumptions can be tricky. We make them because we have no hard data on any civilization outside our own. About this one, we might ask: Why should there be any universal ‘timeline’ of development? Are there ‘plateaus’ when the steep upward climb of technological change goes flat? Soon we have grounds for an ever deeper debate. What constitutes civilization? What constitutes intelligence, and is it necessarily beneficial, or a path toward extinction?

Image: The Arecibo Observatory in Puerto Rico, from which a message was broadcast to the globular cluster M13 in 1974.

Airing out the METI Debate

I want to commend Johnson’s piece, which is titled “Greetings, E.T. (Please Don’t Murder Us.” As you can fathom from the title, the author is looking at our possible encounter with alien civilizations in terms not of detection but of contact, and that means we’re talking METI — Messaging Extraterrestrial Intelligence. What I like about Johnson’s treatment is that he goes out of his way to talk to both sides of a debate known more for its acrimony than its enlightenment. Civility counts, because both sides of the METI issue need to listen to each other. And the enemies of civilized discussion are arrogance and facile assertion.

It was Martin Ryle, then Astronomer Royal of Britain, who launched the first salvo in the METI debate in response to the Arecibo message of 1974, asking the International Astronomical Union to denounce the sending of messages to the stars. In the forty years since, about a dozen intentional messages have been sent. The transmissions of Alexander Zaitsev from Evpatoria are well known among Centauri Dreams readers (see the archives). Douglas Vakoch now leads a group called METI that plans to broadcast a series of messages beginning in 2018. The Breakthrough Listen initiative has also announced a plan to design the kind of messages with which we might communicate with an extraterrestrial civilization.

All of this will be familiar turf for Centauri Dreams readers, but Johnson’s essay is a good refresher in basic concepts and a primer for those still uninitiated. He’s certainly right that the explosion of exoplanet discovery has materially fed into the question of when we might detect ETI and how we could communicate with it. It has also raised questions of considerable significance about the Drake Equation; specifically, about the provocative term L, meant to represent the lifespan of a technological civilization.

Johnson runs through the Fermi question — Where are they? — by way of pointing to L’s increasing significance. After all, when Frank Drake drew up the famous equation and presented it at a 1961 meeting at Green Bank (the site of his Project Ozma searches), no one knew of a single planet beyond our Solar System. Now we’re learning not just how frequently they occur but how often we’re likely to find planets in the habitable zone around their stars. The numbers may still be rough, but they’re substantial. There are billions of habitable zone planets in the galaxy, so the likelihood of success for SETI would seem to rise.

And if we continue to observe no other civilizations? The L factor may be telling us that there is a cap to the success of intelligent life, a filter ahead of us in our development through which we may not pass, whether it be artificial intelligence or nuclear weaponry or nanotechnology. METI’s critics thus worry about planet-wide annihilation, and wonder if a limiting factor for L, at least for some civilizations, might be interactions with other, more advanced cultures. Far better for our own prospects if the ‘filter’ is behind us, perhaps in abiogenesis itself.

Hasn’t our own civilization already announced its presence, not just through an expanding wavefront of old TV and radio shows but also through the activity of our planetary radars, and the chemistry of our atmosphere? After all, even at our level of technology, we’re closing in on the ability to study the atmospheres of Earth-class planets around other stars. If this is the case, are we simply being watched from afar because we’re just one of many civilizations, and perhaps not one worth communicating with? METI proponents will argue that this is another reason to send a message: Announce that, at long last, we are ready to talk.

The counter-argument runs like this: A deliberately targeted message is a far different thing than the detection of life-signs on a distant planet. The targeted message is a wake-up call, saying that we are intent on reaching the civilizations around us and are beginning the process. Passive signal leakage is one thing; targeting a specific star implies an active level of interest. And the problem is, we have no way of knowing how an alien culture might respond.

Procedures for Consensus

In his article, Johnson is well served by the interviews he conducted with with Frank Drake (anti-METI, but largely because he would prefer to see METI funding applied to conventional SETI); METI proponent and former SETI scientist Vakoch; anti-METI spokesman and author David Brin; and anthropologist Kathryn Denning, who supports broad consultation on METI. Johnson does an admirable job in summarizing the key questions, one of which is this: If we are dealing with technologies whose use has huge consequences, do individuals and small groups have the right to decide when and how these technologies should be used?

I think Johnson hits the right note on this matter:

Wrestling with the METI question suggests, to me at least, that the one invention human society needs is more conceptual than technological: We need to define a special class of decisions that potentially create extinction-level risk. New technologies (like superintelligent computers) or interventions (like METI) that pose even the slightest risk of causing human extinction would require some novel form of global oversight. And part of that process would entail establishing, as Denning suggests, some measure of risk tolerance on a planetary level. If we don’t, then by default the gamblers will always set the agenda, and the rest of us will have to live with the consequences of their wagers.

Easier said than done, of course. How does global oversight work? And how can we bring about a discussion that legitimately represents the interests of humanity at large?

Consultation also meets an invariable response: You can talk all you want, but someone is going to do it anyway. In fact, various groups already have. In any case, when have you ever heard of human beings turning their back on technological developments? For that matter, how often have we deliberately chosen not to interact with another society? Johnson adds:

But maybe it’s time that humans learned how to make that kind of choice. This turns out to be one of the surprising gifts of the METI debate, whichever side you happen to take. Thinking hard about what kinds of civilization we might be able to talk to ends up making us think even harder about what kind of civilization we want to be ourselves.

The METI debate is robust and sometimes surprising because of what doesn’t get said. Under the frequent assumption that human civilization is debased, we assume an older culture will invariably have surmounted its own challenges to become enlightened and altruistic. Possibly so, but without data, how can we know that other civilizations may not be more or less like ourselves, in having the capacity for great achievement as well as the predatory instincts that can cause them to turn on themselves and on others? Is there a way of living with expansive technologies while remaining a flawed and striving culture that can still make huge mistakes?

We can’t know the characteristics of any civilization without data, which is why a robust SETI effort remains so crucial. As for METI, I’ll be publishing tomorrow a response to Johnson’s article from a group of METI’s chief opponents exploring these and other points.


SETI, METI… and Assessing Risk like Adults

David Brin is a familiar name to science fiction readers worldwide, the award-winning author of the highly regarded ‘uplift’ novels that include Startide Rising (1983), The Uplift War (1987) and Brightness Reef (1995). Among his numerous other titles are The Postman (1985), Kiln People (2002) and Existence (2012). But Brin is also known as a futurist whose scientific work ranges over topics in astronautics and astronomy to forms of dispute resolution and the role of neoteny in human evolution. His Ph.D in Physics from the University of California at San Diego followed a masters in optics and an undergraduate degree in astrophysics from Caltech. He was a postdoctoral fellow at the California Space Institute and the Jet Propulsion Laboratory. Brin has served on advisory committees dealing with subjects as diverse as national defense, space exploration, SETI and nanotechnology, future/prediction and philanthropy. His essay The Great Silence (available here) is but one of his many investigations into SETI and METI that weigh the consequences of contact with other civilizations, a subject that occupies him in the post below.

by David Brin


In a previous Centauri Dreams posting (SETI, METI and Existential Risk), J.N. Nielsen made an earnest effort to appraise both sides of the current debate over “messaging” to the cosmos, or METI. He started with an apt comparison to the way that passive-listening sonar differs from the brashly-seeking active kind — the “pinging-and-echoes” we’ve all heard in submarine movies.

Alas, he then poses the current dispute over METI in oversimplifying terms: “Is the universe such a dangerous place that it behooves us to maintain radio silence?”

This posits a glaring misapprehension — that the dissidents who mistrust METI are acting out fear of the unknown, dreading possible consequences of shouting for attention into the sky. In fact, however, Dr. Jim Benford, the late Dr. John Billingham, former senior US diplomat Michael Michaud and I have all resigned from SETI-related international commissions — and taken the matter public — in protest over behavior that has taken on an increasingly cult-like quality.

This troubling trend became apparent a couple of years ago, the one and only time that a substantial and open discussion of the matter took place in a neutral and respected venue, before a special gathering organized by the Royal Society. The proceedings of that gathering will soon be published by the Journal of the British Interplanetary Society, and I urge all interested readers to keep their eyes open for that event, when the whole matter will be laid out before you all, in far greater detail than I can do here.

(For those who are impatient to learn more (a trait I find most-becoming!) here is a link to articles and speculations by David Brin about the Search for Extraterrestrial Intelligence (SETI).

Keeping my response to Mr. Nielsen succinct in this place, let me say that he gets the “dissidents’ motives entirely wrong. We freely admit that the odds of any one bad-outcome scenario from METI broadcasts or beams might be small. We are, however, capable of admitting one thing that METI zealots obstinately refuse to avow — that we don’t know what those odds are, not even within many orders of magnitude. In the new and important realm of Risk Analysis, that kind of uncertainty ought to prompt adults to at least talk about ways to reduce the uncertainty.

But talk and discussion and appraisal of risk are exactly what the zealots — aided and abetted by certain folks at the SETI Institute — bend all their efforts to avoid. The Royal Society meeting was a fluke and efforts to expand the discussion are met with stony silence or open disdain.

To make things perfectly clear, what we METI dissidents have asked — and ALL that we have asked — is for a series of open, eclectic, vigorous and thorough discussions to be held, probing this matter of risk from all sides, before individuals and small groups jump the gun, peremptorily blaring yoohoo ‘messages,’ arrogating the right to speak to aliens on behalf of all humanity. So far, these stunts are being pulled by a small subset of radio astronomers and fans — or commercial owners of tracking dishes that had been built by taxpayer funds — who deliberately avoid collegiality with other sciences, fleeing input from experts in pertinent fields like history, biology, anthropology, planetary science or, indeed, any other discipline that might shed light onto a vast range of conceivable outcomes from First Contact.

Some of which (by the way) do not depend upon any ability to travel physically between the stars.

At risk of tedious repetition, because it has proved relentlessly necessary — all that we dissidents have asked for has been the kind of earnest and eclectic pre-discussion that worked so well, decades ago, when the genetic biology community engaged in the extremely successful and positive sum “Asilomar Process” to explore their then-nascent field and thereupon decide on procedures to get both safety and rapid discovery.

That has been our request and position. Anyone who claims that we have sought anything else — out of “fear of slathering Cardassian invaders,” snarked one deceiver — is a damned liar.

(By the way, just envision those open and public symposia I talked about, drawing on all realms of pertinent human excellence, revolving around every topic that might shed light upon either aliens or ourselves. Wouldn’t such symposia make for terrific television? Might they not capture the imagination of — and edify — millions or even billions? Why would anyone oppose such exposure to the full range of ideas and analyses or our place (and possible others’) in the universe? The pro-METI opposition to this speaks a lot about their honesty and fealty to science.)

Getting down to specifics

Having explained that key point, let me go on to say that Mr. Nielsen shows a calm logic that would be welcome in any discussion. Alas, he also displays the blithe assurance we see all-too often in this field — and that was rife among the commenters underneath his posting — that one does not have to read-up any of the background material, in order to be an instant expert. Just arm-wave a pat few sentences of “logic” and you’ve solved the most perplexing puzzle in the cosmos!

Nielsen’s dismissal of the Benford paper on interstellar communications economics – for example – is toe-shallow. Indeed, does Nielsen contend that advanced ETCs — no matter how rich they are — would not still very likely prefer one means of making contact that is six to ten orders of magnitude cheaper than another?

A factor of a million or a billion may affect your choice of method, even if you are a super-Kardashev society of near-gods.

Thus, the Benfords clearly proved that “pinging” potential new civilization sites – at intervals – would be far more efficient and likely than gaudy, omni-directional beacons. Indeed, that strategy is consistent with the famous “Wow” signal… and with the fact that no gaudy, omni-blaring tutorial beacons have ever been found. The one null-result of SETI that is already definite, sufficient and proved.

Nielsen is at his best – though still very superficial – in discussing possible ways and reasons for intentional silence. Certainly I have listed in my Great Silence catalogue many variations on that theme, ranging from cowering dread all the way to beneficently allowing Earth culture to grow without cultural interference. Indeed, some of these are drawn out dramatically in my novel Existence. Still, I have trouble when Nielsen says the following:

“…just as these peer civilizations would likely incorporate our curiosity about the universe, they would also likely incorporate our willingness to take risks.”

This is yet another blithe assumption, a dilettante arm-waving that begs, rather than asks key questions. Nielsen posits that the descendants of the alien equivalents of bears or lions or geese or herbivores would share a similar psychology with we humans, who happen to come from exogamously-exploring, gregariously-interdependent yet individualistic apes, a combination that is – in truth – rather rare in nature. Oh, sure, there may indeed be others like us! But then his broad generalization is broken.

Add to that the social effects we’ve seen, in which 99% of human societies strove hard to repress curiosity and inventiveness, and you have reason to suggest that Mr. Nielsen talk things out and expose his assumptions to critical scrutiny. Preferably before publication.

Like the following:

“If our civilization determines that METI is too great an existential risk to bear, then existential risk perception begets risk aversion and possibly culminates in permanent stagnation.”

Um… where on Earth did THAT come from? Yes, I just said that most human societies squelched curiosity. But that was a personality trait arising organically from feudalism, not an outgrowth of any single act of risk analysis.

The crux

Our exceptional enlightenment civilization is outgoing and daring — traits that other human societies would have deemed foolish but that we consider noble. That spirit is under siege right now, as forces try to re-assert feudalism. But one thing is for sure. A little pre-discussion about the highly outward-looking topic of extraterrestrial civilization is not going to be the thing to bring down a curtain of stagnation! Our outwardness will not change if we act with a little prudence and pause to analyze METI risk factors, like adults. The way the biologists did, at Asilomar. Mr. Nielsen is presenting us with a strawman, and a deeply pernicious one, at that.

Indeed, no one on this planet has pursued Otherness and exploration of the topic of the alien more relentlessly than I have, in both fiction and in science. I do not view the cosmos with trepidation. I am proud to be a member of the only civilization on Earth (and perhaps anywhere) that ever stared at the stars with eagerness, salivating with intense hunger.

But overlaid upon both curiosity and romance is something else called maturity. I have children. Care for their posterity is a duty I intend to fulfill. If that means spending a decade listening and learning and discussing, instead of yammering like idiots into a cosmos that is unexpectedly and perhaps dauntingly quiet? Well then call me the adult in the room.

To impatient adolescents that is a crime. Well then…. mea culpa.

On the other hand, maybe folks could stop yelling “gotcha!” in a topic that is actually rather complex. Indeed, those complexities are the spice, the juice, the excitement in this field. If your contribution is a quick, snarky “of course” about… aliens? Well… take my word for it. You have no idea what you are talking about.


James Benford: Comments on METI

Pardon this extended introduction to Jim Benford’s response to Nick Nielsen’s Friday essay, but it comes at a serendipitous time. Jim’s recent online work has reminded me that we in the interstellar community need to work to see that as many resources as possible are made available online. In the absence of specialized bibliographies, useful information can be hard to find in more general indices. And it’s always dismaying to read an intriguing abstract only to realize that the paper itself is behind a pricey firewall. Access to academic libraries certainly helps, but online databases still vary in what they make available, which is why I always check the home pages of the authors of a given paper to see if they have posted a copy of their work themselves. Scientists can do much to get the word out, as Jim’s new site attests.

You’ll find it at Over the weekend, after Nick had discussed METI (Messaging to Extraterrestrial Intelligence) on Friday, I resorted to Jim’s site to pull the Benfords’ key papers on cost-optimized interstellar beacons back up on screen. Preprints of these are available on the arXiv site, but how much more useful to have a single site with a researcher’s papers not just in preprint but in final form. Jim and brother Greg’s work on how beacons might be built, what their broadcasting strategies would likely be, and how we might go about finding them is moving SETI in interesting directions and it’s all here in one place.

So are references to Jim extensive work on microwave beaming to sailcraft, on fusion and pulsed power and plasma physics at large. Here we’re still limited to bibliographic entries because of publishers’ policies, but the bibliography is itself a valuable tool, and we can hope, as publishers gain more experience with networked resources, that open access to scientific work (particularly that funded by taxpayers!) will increasingly become the norm. Interstellar studies needs good bibliographers and researchers can help by cataloguing their own work.

But enough of this extended introduction to the response Jim sent to Nick. What to do about sending messages to other stars? For that matter, just how far are our own electromagnetic signals traveling? We have much to learn as the investigation continues.

by James Benford


I’m very pleased to see Nick Nielsen’s essay. Fits my attempts to widen the discussion of METI. METI is an issue that really should be debated further; as it is increasingly possible that someone will announce us. These are not easy questions; they are ultimately social questions, so should be widely discussed.

I would suggest another paper of mine which treats METI directly. It’s in the Special Issue of JBIS on the METI Debate that I am editing:

“Costs and Difficulties of large-scale METI, and the Need for International Debate on Potential Risks”, John Billingham and James Benford, in press, JBIS (2014).

A draft version is on my new website, at

A few comments:

1) Opponents of METI do not ‘maintain that the “leakage” of the ordinary (unintentional) EM radiation of a technological civilization cannot be detected at interstellar distances”. No, they say just that past signals are undetectable using our present and projected technology. Future leakage may well be larger – see the following point.

2) Several of the responses to my quantitative arguments showing that neither Earth-scale radio telescopes or even the Square Kilometer Array (SKA, that radio astronomers hope to build, but have yet to find the funding for) are able to detect leakage radiation or messages from our radio telescopes only at very limited range of at most a few light years. Their responses simply say that ETI will have far larger radio telescopes as big as Chicago or New Hampshire.

It’s not that easy. Such assumptions are not without implications. The proper scientific thing is to consider the implications of such assumptions. Larger-scale civilizations will leave larger footprints.

If we use Claudio Maccone’s statistical argument that results in the nearest ET civilization being roughly 1000 light years away, no message we can transmit from Earth within the limits of our technology would be detected unless the receiving civilization were substantially wealthier than us, by a factor of 1,000. The details: If we use the ability to build larger area radio telescopes as an indicator of the scale of civilization, that means the energies consumed, and so the wealth, should be larger by a similar amount.

Are there observable features of such civilizations? I think so, especially if they are nearby. If there were a civilization at Alpha Centauri with 1,000 times the energy consumption of earth, they would be able to do extraordinary things. They might modify their climate, beam power around their solar system, construct and launch starships, such as the ‘sailships’, beam-powered sails that Project Forward is conceptualizing. They would be observable.

So just imagining that ET is far more powerful than we are is not a simple escape clause from the arguments I made.

3) My work with John Billingham shows what METI would cost us: ~ 10 B$ for 1000 light year range. Countering METI would cost more than METI, but of same order. To suppress METI, radiate the same signal exactly 180° out of phase so that it cancels, suppressing the message.

4) “Energy and material limitations will cease to be relevant for all practical purposes.” That’s doubtful, as economic history shows. I remember when nuclear power was going to make electricity ‘free’. Didn’t happen. What does happen is prices for some things fall. For example Al, rare before 1800, now used for Coke cans.

5) Spectroscopy of exoplanet atmospheres could reveal markers of life like oxygen, but markers of civilization are very hard to see. Can anyone give an example of something detectable? CFCs aren’t, they’re too small.