New Approaches on What the Fermi Paradox Means for the Future of Humanity

I was lucky to attend a video lecture by James Miller, economist at Smith College, facilitated by Joshua Fox. Thanks for having this event! I contacted James to let him know I would be posting this and to let him proofread my recapitulation of his argument so as to avoid mis-paraphrasing him; my thanks to him for taking the time to correct me on several points. Of course any errors are mine.

Much of this is familiar terrain for those of us who spend our time considering X-risk and the Fermi paradox. Miller's thesis is that we are at a critically important point in human history, a window where we think that in the near future we can start colonizing the galaxy (the year 2614 at earliest, by this calculation) but at the same time where we are smart enough to destroy ourselves. Since it is not obvious that the galaxy has already been colonized by other civilizations, there may be a Great Filter stopping this from happening. Miller uses the analogy of a person about to climb a mountain, believing that everyone else who has attempted it has died in the process.

Several challenges were discussed by attendees. (If you attended the lecture and want to claim credit for your question, please comment below, thanks.)

1. It's too early to say there are no civilizations; it may not be so easy to detect them or rule them out. We're still discovering metazoans in Manhattan so it seems a little early to rule out von Neumann probes on low gravity bodies in the solar system. We've barely begun to catalog the fauna of our own ocean floors. We could not detect a twin Earth emitting the same radio energy (the C-index), even if it was orbiting Alpha Centauri. Miller points out that even if there were only a few civilizations in the Milky Way preceding us, "the galaxy is older than it is big", and these earlier civilizations could have colonized it already.
   
   
2. He made the point that the things which prove advantageous in the midst of evolving on a single planet might have no such advantages in terms of galactic colonization. Very true; I would argue that we are much more likely to find alien artifacts, than the aliens themselves, as all of us meat-creatures might be stuck on our planets while our machines colonize the galaxy. To that end, (my point) it's entirely plausible that the Solar System could be littered with space probes and we haven't found any yet, or did, and just didn't know what we were looking at.
   
   
3. I would therefore extend Miller's analogy like this. Only in the process of climbing the mountain, does our climber develop wilderness skills and begin to see things that resemble his own boot tracks, etc. and finally as he approaches the summit realizes that lots of people have climbed it, come down the other side, and their descendants have built large villages which due to his previous ignorance he has not been able to locate. (Or, maybe just some of their livestock, trained birds-of-prey, etc. have made it.)
   
   
4. Active attempts to bring ourselves to the attention of aliens have occurred (METI) and been roundly criticized. Miller notes that the risk of extinction from aliens over the next few centuries is lower than eg bio-terrorism or an intelligence singularity. True; but we still may be making life more difficult for our descendants. Related to this, he proposes an ingenious experiment that for a month we should shout our heads off electromagnetically, and see if there is any strange activity. While I agree it's unlikely we'll get invaded next week, I still think the risk:benefit does not work out and there are just too many unknowns, and we may be screwing our distant descendants. Miller suggested that enforcing a moratorium on METI-like activities is probably impossible.
   
   
5. He argues that technological singularities of the paperclip maximizer variety are unlikely to be a major contributor to the Great Filter, because we would be able to see the boundary of it as it expanded (unless it was doing so at light speed.) My concern with this is that, while an AGI might be much smarter than its creators, it is still not omniscient, and the impact of its actions could in principle still outstrip its ability to predict that impact. This is the story behind the rise of human intelligence and the sixth great extinction that we're living through, but has happened in pulses of endogenous extinctions throughout Earth's history (the rise of superpredators every fifty million years or so, the Oxygen Catastrophe). The lesson of evolution here on Earth is that the smarter things are, the faster their behavioral plasticity "catches up with them" in exactly these sorts of disasters, so to suppose that alien paperclip maximizers are immune to this problem is to argue that a qualitative change in ecological dynamics has occurred.
   
   
6. There were two (possibly unappreciated) related questions asked: one about civilization perhaps being bad for sustaining civilization (witness declining birth rates in the developed world) and another that intelligences might prefer virtual reality - involution - to expanding into space. Miller points out the passive version of the "baseball bat" problem: you can live in heaven, but if a bad guy comes and bashes your server with a club and you as you sleep in your VR pod, that's the end of it. (Related: dynamic complex systems like minds, in principle, tend to drift toward delusion and suffer inherent cyclic crises.) It's a thesis for someone in psychology or a related field to note whether there is causation or just correlation between the increasingly encompassing virtual reality-like entertainments available in the developing world, and declining birth rates.
   
   
7. One questioner asked about the distinction between intelligence and civilization - humans have had a "civilization" only since agriculture. This was a really original line of thought. Therefore, there could be many alien intelligences, but few or no civilizations. One solution for humans avoiding the Great Filter would be to abandon civilization and go back to hunting-gathering - not directly suggested, but this is the only implication of such an argument I could think of. The extreme number of assumptions built in to discussion of alien civilizations should always be pointed out - civilization is something that collections of human nervous systems do, and it is not clear it is a necessary consequence of intelligence. (As a physician I ask: do we assume the aliens will have similar EKG waveforms and liver enzymes as us? No, because that's ridiculous. So we do we assume that the even more complex activity of another organ, that we don't even share with other animals on this planet, is automatically going to be meaningfully similar?)

There's also a psychological point to be made about "big picture" arguments (the singularity, the Fermi paradox, the simulation argument, etc.) They have a tendency to converge on either prophetic religion-like conclusions (e.g. the singularity as the rapture for nerds) or Lovecraft (the estivation hypothesis, which was mentioned in a question and made me think about this.) When we talk about these things, there are many many unknowns. In such discussions, I think there is a tendency for the resulting arguments to resemble the internal contours of the human mind, more than any future events in the actual external world; hence their regression to religion-like conclusions. This does not mean such an argument must be incorrect, but it should make us suspicious when a big-picture argument hews too close to our "ontological test pattern. "

Consider in contrast cosmologists' models of the distant future of the universe, which concern physical objects which we can now observe and characterize, using rigorous mathematical rules. These models often seem boring, meaningless, difficult to understand, and unsatisfying. This is exactly how we should expect most models will seem of things outside our own and our ancestors' experiences, or beyond the scale of time and space to which we are accustomed and which we are built to perceive; the further outside their experience, the moreso. This occurred to me when we were discussing the estivation hypothesis, though overall Miller's arguments do not set off many alarm bells for this quick-and-very-dirty heuristic.

New Estimate for Number of Active Civilizations in the Milky Way

A summary:

• At a lower bound, it's estimated on average there is one 17,000 LY away. The number that is being reported is that this means at least 36 civilizations in the galaxy.
  
  
• They mention the problem of relying on M-class stars as abodes for life - because they're quite unstable (flares). I have not read the paper in detail, but it seems hard to understand, if there are only 36 star systems, why those couldn't all be G-class stars.
  
  
• They also estimate a lower bound of communicating for only a century (since we've been communicating for that long so we know it's possible.) If it's only a 100 year period, if we're hearing them now, they were active before agriculture.
  
  
• There's also the problem of being able to discern signal from noise at that distance - and not knowing what type of signal we're looking for. A useful thought experiment is the C-index, which is the distance at which we could detect a twin Earth with identical EM emissions. By most estimates, even if there were a twin Earth orbiting Alpha Centauri, we still today could not hear them. This leads the authors to conclude that interstellar communication is for all intents and purposes impossible.
  
  
• Therefore, any persisting civilization is plausibly more likely to be detected by self-replicating artifacts. This all reinforces the greater relative importance of looking for artifacts in our own solar system, which is something we can conceivably do with known technology in the near future, with less of a signal-to-noise problem.
  

Westby T. and Conselice CJ. The Astrobiological Copernican Weak and Strong Limits for Intelligent Life. The Astrophysical Journal. 2020 June 15.

Attempts at Interstellar Communication: Receipts and Responses Within Your Lifetime

tl;dr Lots of scientists are on record saying that broadcasting messages to nearby stars is dangerous. If you take other low-probability high-consequence existential risks seriously, you should consider joining the effort (resources here.) Compared to some of the problems the X-risk community is used to thinking about, it would be relatively easy to stop active SETI (METI) and protect the future of life on Earth.

A very philosophically-minded Native American in the pre-Columbian era, sitting on the beach at night, might have thought: there might be a beach just like this one, far across these waters. And if we set up large bonfires, we can let them know we're here! What a joy it would be to meet and exchange culture and technology! We know how the exchange actually played out; if it had come a few centuries earlier, it would have been the Norse landing in New England and Virginia, and likely would have been even worse. In any event, if our pre-contact philosopher would've known exactly how friendly those people across the water would be, he would've abandoned his plan.

This was the result of contact between two groups of the same species that had been briefly (in biological terms) separated. Based on simple evolutionary psychology, contact between two completely unrelated species would likely be much, much worse. But in contrast, revealing the strangely and hypocritically self-flagellating psychology of certain people, you don't have to look far for arguments that contact between humans and aliens would necessarily be beneficial to us - because we humans are so dirty and sinful (except for the people pointing out how sinful we are of course), and any aliens technologically advanced enough to visit us[1] would necessarily be morally advanced as well (again inconsistently, morally advanced as evaluated by the sinful human making the argument.) There's no valid argument in favor of METI, and every reason to think it should be considered suicide for Earth's entire ecosystem, not just for humans. And yet it's been done repeatedly, sometimes for reasons as silly as art projects.

Consider the following list of stars that have been targeted for such contact attempts, and which are close enough that a response (or a visit, if they can travel at light speed) could be received in the medically optimistic lifetime of someone born recently.

Star	Sun-like?	Planets?	Earliest Response
Teegarden's Star	red dwarf	possible	2036
GJ83.1	red dwarf (flare)	no evidence	2040
GJ273b	red dwarf	YES, SUPER EARTH IN HABITABLE ZONE	2043
Gliese 581	red dwarf	YES, POSSIBLY IN HABITABLE ZONE	2050
Altair	white (A)	no evidence	2051
GJ526	red dwarf (flare star)	unlikely	2059
HIP 4872	red dwarf	no evidence	2069
Kappa Ceti	YES, but frequent flares	no evidence	2069
HD 245409	cool orange/hot red dwarf (K-M)	no evidence	2077
55Cancri****	YES	YES, POSSIBLY IN HABITABLE ZONE	2085
HD 10307	YES	unlikely (companion)	2085
47 UMa**	YES	possible	2093
Gl 777	YES	possible	2103

*Where there are asterisks, numbers of asterisks = # of contact attempts

This is by no means an exhaustive list of all messages, only those for which we can receive a response by 2110 - and only those which are publicly reported.

The argument against active SETI (or METI; Messaging ET Intelligence) is simple. Any aliens which receive the message and have the ability to travel to our solar system are very likely far advanced. Whether or not they intend to harm us - if they, it, etc. even has "intentions" - is immaterial, as any contact with them is overwhelmingly likely to be catastrophic for Earth's ecosystem as a whole, including the human race. Arguments that the aliens will be (or for some reason must be) "nice" are comically narrow-minded and provincial.

The best arguments in FAVOR of active SETI appear to be 1) if we remain silent, then we can infer other species are likely to have made the same decision and it's inconsistent to remain silent but keep listening. 2) Advanced species probably already know about us, and these efforts don't much increase the chances of being detected.

To #1, even assuming the self-indication assumption-reasoning here doesn't demand bizarre causality as Nozick argued with respect to Newcomb's Paradox, given the likely severe consequences of a visit from a species more advanced than our own, I think joining in with all the silent species and being part of the problem (i.e., leading to the Great Silence) is quite a good trade. Notice that in our own ecosystem, most animals are quiet, unless they can quickly escape by flight or into burrows, are hidden by darkness, or are surrounded by conspecifics. Those of us who assume that aliens must be friendly somehow always insist that natural selection stops applying to advanced species and across interstellar space.

To #2, if the best argument really is that "they already know we're here so we're not increasing our chances of detection by potentially destructive aliens THAT much", which is literally the argument made by Jacob Haqq-Misra, Chief Scientific officer of the Lone Signal project, then that tells you a lot about how well-thought -through the whole enterprise is. What's more, it's absolutely false. The C-index is a quick and dirty measure of our detectability - if there were a twin Earth, giving off the same amount of electromagnetic noise that we are, how close would we have to be to detect it? Currently, about 3 LY, meaning we wouldn't even be able to hear ourselves from the next closest star. A powerful directed message on the other hand would be much easier to detect from a longer distance - so these messages are in fact likely increasing the probability of our detection substantially, at least at the target stars. Otherwise why are they even sending them?


These projects are ongoing. The problem has been discussed at conferences with approaches including a moratorium backed by international law (so far only talk.) These things are slow. One approach may be to go directly to the telescopes sending the messages, as there are a limited number of such installations. In decreasing magnitude of offense with those messages, they are:

Eupatoria (Crimea, Ukraine) - 7 targets, 11 transmissions
Arecibo (Puerto Rico, USA) - 4 targets, 4 transmissions
EISCAT (Tromso, Norway) 1 target, 1 transmission (an art project!)
Jamesburg (Carmel, California, USA) 1 target, 1 transmission (crowdfunded!!)

In addition, Alexander Zaitsev is a Russian astronomer who is far and away the individual most responsible for driving METI efforts. Douglas Vakoch is a METI proponent here in the US.

Lots of scientists are on record saying that broadcasting messages to nearby stars is dangerous. If you take other low-probability high-consequence existential risks seriously, you should consider joining the effort (resources here.) Compared to some of the problems the X-risk community is used to thinking about, it would be relatively easy to stop METI and protect the future of life on Earth.

[1] I purposely avoid the word civilizations, because that is a term which describes an entity with certain characteristics that humans can collectively form. Whatever activities groups of aliens form, it will not appear like any "civilization" we would recognize. "School", "herd", "flock", "swarm" are all terms that are at least as likely be useful to human impressions to describe the collective entities that we see.

Influence of Interstellar Proximity on Interstellar Exploration and Evidence of Extraterrestrial Visitation

It's easy to despair at the gulf between stars and the millennia of time it would take to get a ship there. The fastest spacecraft humans have yet produced was Helios 2, which after a slingshot maneuver in 1989 was moving at about 103 kilometers per second. There are two things to note about that statement. The first is that it was a slingshot maneuver, not an acceleration achieved under its own power (which is always the case in space exploration.) The second is that breakneck speed would deliver Helios 2 to our nearest neighbor Alpha Centauri right around 13,000 years from now. (This also means there are stars in our neighborhood that even if we aimed our fastest-yet probe at them, we could never reach, because they're moving away from us faster than our fastest spacecraft.)

Those frustratingly quarantine-like time spans suddenly seem much shorter when we consider the geologically brief time spans between close passes of the sun and nearby stars, resulting from proper motion. These changes in interstellar geography actually occur much faster than plate tectonics. In the space of a few tens of thousands of years we might go from having our nearest neighbor five light years away, to close enough to impinge on the Oort cloud and send comets falling toward the inner system. It's amazing to think but since our ancestors were first using fire, multiple close-passes between other stars have occurred. Merely 70,000 years ago we had a star 0.82 light years away (Scholz's Star), and in another 1.3 million, we'll have another (Gliese 710).


There are a number of clear inferences to be drawn from the frequency of such close passes.

1) It bears repeating, in geologic time, 70,000 years is really not long. Humans may have already started leaving Africa when this occurred. We should assume the sun is not unique in this, and our close-pass rate is about once per million years. That means, since the solar system formed, this has occurred 4,500 times. The Wild-2 comet, from which we retrieved material that we've analayzed on Earth, has a nitrogen isotope ratio that strongly suggests it's a comet formed around another star. It also has the amino acid glycine.

2) Impact ejecta from large bodies like Earth can make it into orbit. We have Martian rocks here on Earth from such events having happened on Mars. Space is not hospitable, but even metazoans have survived fairly harsh exposures; for example, C. elegans worms from space shuttle Columbia experiments survived uncontrolled re-entry and were found alive on the ground weeks after the crash. They weren't even protected inside large space rocks. Some exobiologists expect that for this reason, if we do find life elsewhere in the solar system, it will be related to life on Earth (ejected and diffused during the Archaean?) essentially a long-lost branch of archaebacteria. While such a process would be less likely, i.e. take longer in the much greater volume of the outer solar system, if it is not less than 1 in 4,500, it has probably already occurred.

3) It is very likely that the amazingly short 66 years from first manned powered flight to first human on the Moon occurred in part because of the Moon's relative proximity. More than twice that duration has now elapsed and we are still only in the talking stages about a landing on Mars. A species that has the good fortune to "come of age" in terms of space faring technology, when the next closest star is a mere 0.82 light years from their own, has an easier task of proving the possibility of interstellar space flight than we do, coming of age when we're about equidistant from everything. We might therefore narrow our search for intelligent life to super-Earths around sun-like stars with close neighbors. (Of course, there is also a not-unreasonable argument to be made that close passes, or any distant large bodies disturbing the local Oort cloud, increase the chance of major impact events and decrease the chance of the kind of complexity developing that would allow long-distance space travel.) It's worth noting that in view of the high frequently of close passes, a problem for the Oort shower hypothesis of mass extinctions is that it does not happen more frequently, i.e., every million years.)

4) Recalling that our fastest spacecraft have all used gravitational slingshot maneuvers - while we might speculate wildly about the amazing propulsion technology visiting aliens would have, we can be 100% certain that they will have gravity maneuvers at their disposal, because we use it. It's easy and cheap (free, really.) Therefore, there may be interstellar "backwaters" that will not necessarily be empty spots in the galaxy, but places that are difficult to approach from nearby stars and then slingshot away from to another nearby star. If you're a species in such a backwater, you're not going to get visited very much, and you'll ask "Where is everybody?" As the stars shift, your interstellar geography status may change quickly, within a few thousand years. One of the problems with detecting aliens, particularly well-advanced ones, is we don't know what we're looking for. We may be looking right at evidence of their existence and miss it because they don't use our provincial communication methods, or because we're used to it and we explain it in terms of the background operation of "dumb matter". Or, the periodic mass extinctions that are sometimes claimed to be associated with close passes could in fact be associated with close passes - but because of an ecosystem-collapsing alien visitation as Stephen Hawking envisions, rather than because of Oort cloud impactors.

Previous post on alien evolution, There's (at least) a 1-in-3 Chance of Life on Europa

What If We Assume We're Surrounded by a Galactic Civilization, and We're Missing It?

Overcoming Bias covers two papers on SETI; importantly, the papers distinguish between the search for artifacts (like Dyson spheres) and the search for communication. There are problems with searching for communication, among them: do we know what medium they'd use, can we understand them, and should we expect the beacons to be on all the time, or just intercept them briefly, like the WOW signal? The search for artifacts can be divided into looking for massive engineering undertakings of far away civilizations that are solar system- or galaxy-wide, and looking for them right here in the solar system where you're reading this. The latter is not a frequently considered approach, but that's why I'm excited for Dawn to finally make it to Ceres; there are specific reasons to think low-gravity bodies with water and organics would be the places to look for evidence of extrasolar technology. (But until there's a probe that lands and gets good chemistry we won't have evidence.)

Yet, we've found no clear evidence as yet. Add to that the argument that if there is any chance different than zero for any species to develop interstellar travel, the galaxy is very likely to already be full - that is to say, if space-traveling life is anywhere, it should be everywhere, because it would be vanishingly unlikely for us to be the first. And we don't see such life everywhere. At this point we can't conclude that no one is out there, but we can be more certain that no one is everywhere out there. Maybe we're looking for the wrong things, but as we look further and include more types of phenomena, the more we find nothing, the more we should assume we're alone or nearly alone as a technology using intelligence.

Hanson's concern is about the great filter. As it seems the evolution of life seems more and more likely in many places, the great silence we observe means that something is stopping all these living things from leaving their homeworlds, and by some arguments that something is more likely to be in humanity's future than our past. One candidate is that intelligence is an evolutionary dead end which causes species to wipe themselves out, which was exactly Fermi's original fear - that intelligence creates a superpredator that not only exterminates its prey but itself. An interesting bit of trivia: we are currently living through a mass extinction at least as bad as the K/T event, and maybe the worst so far on Earth, and we're causing it.

The other question to ask is this: which of the following two propositions is more likely to be true?

1) That life evolves very frequently, and intelligence relatively frequently, but only very few (or no) species make it to the point of interstellar expansion, so that we don't see a galaxy chock full of waste heat from their engineering projects (i.e. that life is anywhere but NOT everywhere);

OR

2) That they are everywhere out there, but we still don't know what we're looking for.

It may be instructive to work backwards. Start with the assumption that we are surrounded by massive (roughly galaxy-spanning) civilizations, as the papers envision them. We've been looking right at them since the first time a human paid attention to the night sky - how could we differentiate them from background? The uncontacted people in the Amazon are surrounded by nation states, and yet for a half century they've been growing up with the sound of planes in the sky, and they haven't inferred the rest of the world.

What are the things we already see that could be evidence? Dark matter is an intriguing candidate just because we understand it so poorly. The absence of obvious life could itself be a hint, i.e. still-extant species are hiding from or destroyed by others.

This is certainly a less depressing alternative than intelligence being an evolutionarily unstable strategy, which of course has nothing to do with its being true. I increasingly suspect that life in the universe is mostly space viroids that when seeded in a large, warm medium, incidentally produce replicators like life on Earth, that is then stuck there, because either it can't travel in space, or it gets smart enough to travel in space and therefore to kill itself.

How Close Are We to Becoming a Kardashev II Civilization?

Kardashev II civilizations have the power capabilities of an entire star. One way to do this would be to capture the star's energy with a Dyson sphere (below).


Futurists and science fiction types (myself included) often over-simplistically extrapolate current, very strange trends (in terms of the rest of history and nature), especially exponential ones. Despite that, people are looking for Dyson spheres for real as part of SETI. I think this program carries so many assumptions that it's doomed; but let's have some fun and say Dyson spheres are for galactic wusses that don't have the stones to just generate the power themselves. If we humans are eventually going to produce enough power to match our own star, how close are we? Is this something that should be discussed during the next election cycle?

Take a guess. Here are the numbers: the current energy output of humans is about 5x10^20 J per year (since this is energy over time, we're really talking about power). The Sun's output is 1.2x10^34 J per year. So how close are we? A factor of 24 trillion, that's how close.


Let's assume, even more stupidly, that our energy curve will continue to rise the way it has in the twentieth century (see above), despite the fact that the vast amount of that area under the energy-time curve (again, power) came from spending stored chemical potential energy in fossil fuels. The curve has gone up 1x10^14 J about every 15 years - arithmetically, not geometrically. At this rate of increase, the sun will have burned out long before we ever match it. (If you want to be a smartass, you could say that this means that we will eventually match the sun's power because the sun's output will drop drastically. But even then the constraint which determines this is the sun, not how fast our energy output grows.)

Another way of looking at it: if you wanted to match the sun's power by burning fossil fuels, then using the energy density of oil, you would have to burn an amount of oil equal to the mass of the Earth, 50 times per second.

What is this, XKCD?

You're saying, "Fossil fuels? Of course you idiot, you can't get to the Kardashev big leagues powering your civilization on combustion engines!" Fine, let's make an Earth out of antimatter, and gradually crash pieces of it into this Earth. You could put out as much as the sun for about a hundred million years, by shooting pieces of the anti-Earth at us at a rate of a million tons per second. (I guess you hold the Earth together with duct tape to keep it from flying apart during all these shenanigans.) Assuming you don't start with the part of the Earth where you're sitting it would probably look cool, but even so I bet you'll quickly be getting some neat-o cancers from all the high-energy photons this produces, and maybe even just diffuse axonal injury knocking you unconscious in minutes. Incidentally my suggestion is to start with Belgium.

Above: Belgium, at left.

There will still be people objecting, i.e. the Ray Kurzweils of the world, that problem-solving abilities (AI) will grow exponentially, and therefore the energy-producing capacity will follow. Fine. The question for them is what is going to power these other exponential trends, at much more mundane time horizons? (Like the singularity that's apparently scheduled for seven decades from now.) If the answer is "AIs will have god-like intelligence and they'll be able to do it and we can't understand", then why shouldn't we also believe doomsday prophets like Harold Camping who say their gods are coming, and make their claim with exactly the same amount of verifiability and comprehendibility? If you think Kurzweil makes sense, you should also read about the economist Julian Simon's commodities bets, because you should agree with him - although I find that singulatarians somehow find reasons to dislike over-optimistic economists, probably mostly just out of mood afiliation and status considerations.

Final answer: we are not going to become a Kardashev II civilization any time soon, and no one really knows how to get there or what this means, because the definition necessarily involves processes we don't understand. But I'm still fine with dropping large amounts of antimatter on Belgium.

ADDENDUM: This is from Wikipedia about the sun's power generation and for some reason I find this shocking.

The power production by fusion in the core varies with distance from the solar center. At the center of the Sun, theoretical models estimate it to be approximately 276.5 watts/m3,[54] a power production density that more nearly approximates reptile metabolism than a thermonuclear bomb.[b] Peak power production in the Sun has been compared to the volumetric heats generated in an active compost heap. The tremendous power output of the Sun is not due to its high power per volume, but instead due to its large size.

Putting it in socioeconomic terms, the sun is like China - the per capita income is actually not impressive but it's huge, so the multiplier is big.

Stop the Lone Signal Project

Story here. There are in fact already protocols established in the event of alien contact, the most important part is that the discoverer must not unilaterally assume they can make decisions for the entire Earth. Here are some reckless, naive, selfish jerks are now sending messages (Gliese 526). This isn't the first time signals have been sent, but usually those signals aren't target at nearby star systems. Gliese 26 is 18 light years away.

If you think I'm being alarmist, then let me just quote Stephen Hawking:

[Hawking states] that intelligent alien life forms almost certainly exist — but warns that communicating with them could be "too risky."

"We only have to look at ourselves to see how intelligent life might develop into something we wouldn't want to meet."

Astronomer Zdenek Kopal may have put it even better when he said "Should we ever hear the space-phone ringing, for God’s sake let us not answer, but rather make ourselves as inconspicuous as possible to avoid attracting attention!" Robert Rood said, "The civilization that blurts out its existence on interstellar beacons at first opportunity might be like some early hominid descending from the trees and calling 'Here, kitty' to a sabre-toothed tiger." (More on this here.)

Imagine Native Americans building signal fires along the coast to make sure that the first Europeans knew where they were. And what resulted was a chain of events between members of the same species. It is absolutely stupid and absurd to assume the outcome could possibly be any better if we're detected and visited by aliens more advanced than ourselves. This team is either not serious about their project, or willing to endanger the whole Earth. This is a classic low probability, extremely high consequence event. Any consequence to our ecosystem from such signals being sent is going to be unimaginably worse than global warming. After all, we may have so much trouble detecting "loud" civilizations out there because they don't last long; maybe a predation factor is missing from the Drake equation.

The Lone Signal project really seems to be about charging people to put text messages in their little beamings to other stars. We're taking these risks so someone can make a few dollars from a novelty project.

Dr. Jacob Haqq-Misra and the Lone Signal team, stop this project. I would support legal action to stop you as well, and readers, if you care about the continuance of life on Earth, you should too.

When They Thought They'd Found Aliens, What Did They Actually Do?

When pulsars were discovered, the team of astronomers took very seriously the possibility that they had detected an alien civilization. And when they thought about what should be done in terms of a response, they also took seriously the idea of restraint, that information about our existence could not be recalled once it had been sent, if it turned out the other intelligences were not benevolent. Other concerns of the team involved how best to disseminate the information.

SETI has now established a protocol to disseminate news of such a discovery, which basically breaks down into 1) confirm, and reconfirm, and reconfirm again before you say anything; 2) go through channels; and 3) no one should talk back to them until a public international discussion is held. This may all be a moot point since people have been sending signals in various directions for some time, and a criticism of Frank Drake for doing just this is mentioned in the paper I linked to (references removed for readability):

Such a signal was in fact sent out by Frank Drake in 1974 and Ryle wrote to Drake complaining that it was "very hazardous to reveal our existence and location to the Galaxy; for all we know, any creatures out there might be malevolent - or hungry". Later, it seems that Ryle led an approach by several people to Sir Bernard Lovell of Jodrell Bank fame who then sent a private letter to the International Astronomical Union raising the possibility of malevolent aliens, saying that "I have been asked to seek a discussion in the Executive Committee ... astronomers are involved in the problem of communication with extraterrestrial communities. Transmissions for this purpose are being made .... [ as to whether] the IAU should draw the attention of world governments to a problem which could conceivably be of critical importance" and "whether the astronomical community should take steps to initiate a wider discussion on an international basis of the consequences of success ... I repeat I raise this issue on behalf of a number of distinguished individuals". After consulting Drake, the IAU concluded that no action was needed.

The C-Index: How Far Away Could We Hear Earth?

The C-Index is a quick-and-dirty way to determine the likelihood of our detection of, and our detection by, other technology-using aliens. Current technology changes over time, and this drives both what we emit (how loud we are), and what we can detect (how well we can listen).

So how close would we have to be to a twin Earth before we could hear it, i.e. hear ourselves? If twin Earth were orbiting Alpha Centauri, could we hear it with our own technology? How about fifty years from now?



In a post at David Brin's blog, he rounds up arguments about our own relative silence by stating "even military radars and television signals appear to dissipate below interstellar noise levels within just a few light years. Certainly they are far less visible -- by many orders of magnitude -- than a directed beam from any of Earth's large, or even intermediate, radio telescopes." (Interestingly, none other than Seth Shostak of SETI is credited with this observation.)

So right now it looks like our C-Index is ~3 light years. If you're interested in this kind of thing you probably already know this isn't even as far as the next closest star, which is 4.3 light years away. They could be right there, chattering just as loud as us, and we still wouldn't know.

Below: the yellow dot is the portion of the Milky Way into which our radio waves have expanded (r=100 LY),  but our current C-index is only 3% of that radius, and therefore contains just 0.027% of that speck.

A Neglected Solution to the Fermi Paradox

The most common answers to Fermi's famous question "Where is everybody?" are some version of either "we're unique", or "something makes intelligent species short-lived on geological time-scales". This second category corresponds to Drake's Omega Factor and could be the result of self-destruction or predation by nearby interstellar replicators.

A far more plausible explanation for our failure to find anything so far is summed up as "They're out there, but we haven't been looking for long, and we don't know what to look for anyway." The good people of SETI have said that so far, all we can conclude that the sky is not littered with constantly-blaring high-power microwave transmitters. Such cautious phrasings are wise. And from such a specific statement as this, are we really able to generalize that we're the only nearby intelligence?

Assuming that intelligence and tool use progress at roughly similar rates in other species, consider the gap in cognition and tools in our own species just over the past 100,000 years. And what is the chance that a planet-bound intelligence would be synchronized even within an order of magnitude of that timeframe? Would H. erectus understand our attempts to communicate? Would we even recognize our own million-year descendants, much less understand them? Now apply that to space-tuna, and you see the magnitude of the problem.

To say we haven't found anything so far, and therefore there are no non-human intelligences, seems foolish. We are barely a half-century into trying to answer this question, and it's not clear that we even know what to look for.

I reiterate that the best place to look for evidence of extraterrestrial replicators are the asteroids and the comets of our own solar system (my reasoning is here.) We should be looking for chemical traces of von Neumann biochemistry, not radio signals grandly announcing their presence. While I don't expect a thorough investigation of these bodies to be completed in my lifetime, I would be thrilled if it were. A lack of findings would cause me to dramatically lower my estimation for the chances of extra-terrestrial replicators.

Hawking Also Says We Should Shut Up

At Boing Boing, Maggie Koerth-Baker points to and paraphrases none other than Stephen Hawking: "For the love of god, everybody just stay quiet. If we're lucky, they won't notice we're here." Hawking joins many others in taking the same position.

By all means, we should try to hear them. But not vice versa. Did Native Americans build signal fires on the shoreline in case anyone in huge ships was sailing by and wanted to exchange their transcendent philosophical ideas?

Perhaps the Fermi paradox is best explained by rational behavior of the organisms involved. And the ones that make noise aren't making it for long.