Searching for Kardashev III civilizations

Fascinating article by Paul Gilster over at Centauri Dreams: Interstellar Archaeology on the Galactic Scale. In the article, Gilster, discusses the work of Richard Carrigan of Fermilab and his recent paper, "Starry Messages: Searching for Signatures of Interstellar Archaeology."

Carrigan argues that we should broaden SETI's scope to include the archeological remnants of Kardashev III civilizations, namely those civilizations who successfully tapped into their Galaxy's entire energy output. At first blush, one would assume that a K3 galaxy would be immediately obvious, with every one if its stars enclosed in a Dysonian structure of some sort. But Carrigan makes the case that this might not be the case:

…what would happen for a civilization on its way to becoming a type III civilization, a type II.5 civilization so to say? If it was busily turning stars into Dyson spheres the civilization could create a “Fermi bubble” or void in the visible light from a patch of the galaxy with a corresponding upturn in the emission of infrared light. This bubble would grow following the lines of a suggestion attributed to Fermi… that patient space travelers moving at 1/1000 to 1/100 of the speed of light could span a galaxy in one to ten million years. Here “Fermi bubble” is used rather than “Fermi void”, in part because the latter is also a term in solid state physics and also because such a region would only be a visible light void, not a matter void.

As Gilster notes, this is long-term thinking in the richest sense; a patient, long-lived civilization could envelop a galaxy on a time-scale comparable to or shorter than the rotation period of the galaxy (considerably >~250 million years).

Civs who are busy turning stars into Dyson spheres should leave vast Fermi 'bubbles' whose infrared signature would flag their existence. But as Carrigon notes, detection might still elude us.

For example, we see M51, the Whirlpool galaxy, face-on at a distance of 30 million light years. We can say with some confidence that we see no unexplained voids larger than about five percent of M51's area, but any void features below this level would be hard to identify because of spiral galaxy structure. Elliptical galaxies might be better places to look for Fermi bubbles, because they display little structure, and potential voids should be far more pronounced.

And then there's the difficulty in separating artificial structure from natural phenomena where the tendency is to defer to the latter.

Gilster concludes:

I come back around to the premise behind interstellar archaeology, that unlike conventional SETI it does not require a civilization to have any intention of contacting us. There are numerous ways to proceed, involving the kind of Dyson sphere search Carrigan has himself conducted within our own galaxy, or looking at planetary atmospheres in hopes of finding not only biosignatures but the markers of an advanced industrial or post-industrial culture. As we continue the SETI hunt, keeping in mind how planetary change or deliberate decisions to expand into the galaxy could leave visible traces allows us to hunt for things advanced intelligence might do.

How many civilizations in our galaxy, for example, have already faced the end of their main sequence star’s lifetime? If the number is high, it may be that we can find evidence of their response in the form of planetary or stellar engineering, making stars of this description interesting targets for future searches. In any case, our model of SETI is changing as not only our technologies but our assumptions become more sophisticated, leaving us to ponder a universe in which the need for expansion or simple survival may have left its own detectable history.

More.

Sam Vaknin: The Ten Errors of Science Fiction

Global Politician columnist Sam Vaknin argues in a recent article that science fiction is guilty of ten specific mistakes when postulating the characteristics of advanced extraterrestrial life. Specifically, he contends that sci-fi writers consistently buy into fallacies about:

1. Life in the universe

2. The concept of structure
3. Communication and interaction
4. Location
5. Separateness
6. Transportation
7. Will and intention
8. Intelligence
9. Artificial vs. natural
10. Leadership

While the article certainly raises some food for thought, Vaknin's call for writers to think more 'outside of the box' is a bit of a stretch, if not condescending. Science fiction writers, for the most part, take great pains to weave a coherent narrative around novel imaginings of what ETIs might look like. Moreover, Vaknin is himself guilty of considerably hand-waving, arguing that ETIs may be existentially and qualitatively of a different sort than what we might expect, but at the same time he doesn't provide any substantive or compelling evidence for us to believe otherwise.

Sure, I agree that ETIs may be dramatically different than what we can imagine and that they may exist outside of expected paradigms, but until our exoscience matures we should probably err on the side of the self-sampling assumption and figure that the ignition and evolution of life tends to follow a similar path to the one taken on Earth. Now, I'm not suggesting that we refrain from hypothesizing about radically different existence-states; I'm just saying that these sorts of extraordinary claims (like alternative intelligences spawning different quantum realities) require the requisite evidence. It's far too easy to fantasize about some kind of energy-based hive-mind living in the core of asteroids, it's another thing to prove that such a thing could come about through the laws of physics [my example, not Vaknin's].

In the article, Vaknin also posits six basic explanations to the Fermi Paradox (and the apparent failure of SETI) that are not mutually exclusive:

1. That Aliens do not exist
2. That the technology they use is far too advanced to be detected by us and, the flip side of this hypothesis, that the technology we use is insufficiently advanced to be noticed by them
3. That we are looking for extraterrestrials at the wrong places
4. That the Aliens are life forms so different to us that we fail to recognize them as sentient beings or to communicate with them
5. That Aliens are trying to communicate with us but constantly fail due to a variety of hindrances, some structural and some circumstantial
6. That they are avoiding us because of our misconduct (example: the alleged destruction of the environment) or because of our traits (for instance, our innate belligerence) or because of ethical considerations

Very quickly, point number one is possible but grossly improbable, points two to five are essentially the same argument—that we don't yet know where, how and what to look for, and point six violates the non-exclusivity principle (explains some but not all ETI behavior). It's odd that Vaknin selected these particular six arguments. There are many, many potential resolutions to the FP with these not being particularly stronger than any other (though point #1 has a lot of traction among the Rare Earthers.). And where is the Great Filter argument, which is possibly the strongest of them all?

Nice try, Vaknin, but the Great Silence problem is more complex than what you've laid out.

Nick Bostrom on the Fermi Paradox [video]

IEET Chair Nick Bostrom discusses the Great Silence with Robert Lawrence Kuhn on Closer to the Truth. Nick and I are totally on the same wavelength here, including our agreement over the suggestion that the discovery of life in the solar system would be bad news.

Is geoengineering an existential risk?

Well, Milan M. Ćirković and Richard B. Cathcart think it's a distinct possibility. In fact, it may even (partly) explain the Great Silence. Check out the abstract to their article, "Geo-engineering Gone Awry: A New Partial Solution of Fermi's Paradox":

Technological civilizations arising on such planets will be, at some point of their histories or another, tempted to embark upon massive geo-engineering projects. If, for some reasons only very recently understood, large-scale geo-engineering is in fact much more dangerous than previously thought, the scenario in which at least some of the extraterrestrial civilizations in the Milky Way self destruct in this manner gains plausibility. In addition, we speculate on possible reasons, both physical and culturological, which could make such a threat even more pertinent on an average Galactic terrestrial planet than on Earth.

Be sure to read the entire article (PDF). Learn more about geoengineering. And be sure to read Jamais Cascio's article, "It's Time to Cool the Planet."

Drake: Use the Sun as a 'magnifying glass' to find ET

SETI founder Frank Drake wants to take the search for extraterrestrial intelligence to the next level by implementing a process called gravitational microlensing.

Microlensing is based on the gravitational lens effect: massive objects can bend the light of a bright background object. This can generate multiple distorted, magnified, and brightened images of the background source. More specifically, when a distant star or quasar gets sufficiently aligned with a massive compact foreground object, the bending of light due to its gravitational field leads to two distorted unresolved images resulting in an observable magnification. The time-scale of the transient brightening depends on the mass of the foreground object as well as on the relative proper motion between the background 'source' and the foreground 'lens' object.

In other words, Drake is essentially suggesting that we use our Sun as a 'giant magnifying glass' by positioning an observatory at a distance of around 500AU from it. Theoretically, the resultant microlense would be so powerful that we could see alien planets—and even their continents and oceans.

He contends that advanced extraterrestrial civs may have been doing this for millions of years already and we need to get with the program. Moreover, Drake says this isn't just a one-way system—gravitational lensing could be used to transmit signals to other worlds as well. Considering that our civilization's entire communications schema is about to go digital, he argues that this may be our best bet to communicate with our celestial neighbors.

Okay, now the bad news. The primary problem I have with Drake's suggestion, aside from the fact that it would take over a hundred years to set the crafts into position (which is more an issue of patience than a technical concern), is that the exercise would likely result in failure. Yes, such an observatory would undoubtedly help us discover more exoplanets—even those teeming with life. But it's unlikely that we'd receive any kind of communication by using it.

Among other things, the Fermi Paradox suggests that the timescales in question would not just allow for a civ to set-up and use gravitational microlensing, but to seed every solar system in the Galaxy with Bracewell probes. Sure, extraterrestrials could set microlenses up, but if they're capable of that feat then they're not too far from being able to send out swarms of self-replicating Bracewells.

Again, like I've harped on time and time again, if there are advanced civs out there, and they've wanted to communicate with us, they would have done so by now.

I'm not suggesting that we bail on Drake's project. Quite the contrary. Let's do it. Let's set up this microlense and see what we get. A negative data point can be just as useful as a positive one. And maybe it'll help us discover Dyson Spheres or other megastructures. In addition, the astrological benefits of such an observatory would be incalculable, so it wouldn't be a complete waste by any means.

We just need to temper the expectations of the contact optimists out there, of which Frank Drake is one.

New theory suggests that we may not be alone after all

Astrophysicist Brandon Carter's long-standing argument against finding intelligent extraterrestrial life has been roundly challenged by a team of Serbian researchers led by Milan Ćirković.

Carter's theory assumed set timescales for two processes: the life cycle of a star and the emergence of complex life. By statistically combining the two Carter concluded that complex life takes longer to emerge than the life-friendly duration of most stars -- with the implication being that intelligence is excruciatingly rare in the Galaxy and we may be alone.

Not satisfied with this conclusion, Ćirković and colleagues Branislav Vukotić and Ivana Dragićević are now disputing these assumptions. In their Astrobiology paper, "Galactic Punctuated Equilibrium: How to Undermine Carter's Anthropic Argument in Astrobiology," they contend that there is no reason to assume life evolves only gradually. They argue life could evolve in fits and starts - mirroring an evolutionary theory called punctuated equilibrium.

The abstract of their paper reads,

Our approach is based on relaxing hidden uniformitarian assumptions and considering instead a dynamical succession of evolutionary regimes governed by both global (Galaxy-wide) and local (planet- or planetary system–limited) regulation mechanisms. Notably, our increased understanding of the nature of supernovae, gamma-ray bursts, and strong coupling between the Solar System and the Galaxy, and the theories of “punctuated equilibria” and “macroevolutionary regimes” are in full accordance with the regulation-mechanism picture. The application of this particular strategy highlights the limits of application of Carter's argument and indicates that, in the real universe, its applicability conditions are not satisfied. We conclude that drawing far-reaching conclusions about the scarcity of extraterrestrial intelligence and the prospects of our efforts to detect it on the basis of this argument is unwarranted.

In plain English, the conditions in the Universe required for the emergence of intelligent life have only recently been established (in cosmological scales). Prior to 'recent times', universal mechanisms were in place to continually thwart the evolutionary development of intelligence, namely through gamma-ray bursts, super novae and other forms of nastiness. Occasional catastrophic events have been resetting the "astrobiological clock" of regions of the Galaxy causing biospheres to start over. "Earth may be rare in time, not in space," they say. They also note that the rate of evolution is intimately connected with a planet's environment, such as the kind of radiation its star emits.

This is why the authors reject a strict uniformitarian approach; the Universe is not the same now as it was in the past.

And importantly, given the possibility that the conditions for intelligence to emerge are now in place, we shouldn't give up hope about our chances of discovering extraterrestrial life.

Assessing solipsist solutions to the Fermi Paradox

Milan M. Cirkovic is guest blogging this week.

Thanks to George Dvorsky for inviting me to blog this week on Sentient Developments.

The title of this post refers to a classic 1983 paper of Sagan and Newman criticizing Tipler's skepticism toward SETI studies based on Fermi's Paradox (FP) and strengthened by the idea of colonization via von Neumann probes. Here, however, I would like to talk about solipsist solutions to FP in a different – and closer to the usual – meaning.

Solipsist solutions reject the premise of FP, namely that there are no extraterrestrial civilizations either on Earth or detectable through our observations in the Solar System and the Milky Way thus far. On the contrary, they usually suggest that extraterrestrials are or have been present in our vicinity, but that the reasons for their apparent absence lie more with our observations and their limitations than with the real state-of-affairs.

Of course, this has been for so long the province of lunatic fringe of science (either in older forms of occultism or more modern guise of ufology) but to neglect some of these ideas for that reason is giving the quacks too much power. Instead, we need to consider all the alternatives, and these clearly form well-defined, albeit often provably wrong or undeveloped ideas. Some of the solipsist hypotheses discussed at least half-seriously in the literature are the following (listed in rough order from less to more serious ones):

• Those who believe UFOs are of extraterrestrial intelligent origin quite clearly do not have any problem with FP (e.g. J. Allen Hynek; for a succinct historical review see Chapter 6 of Dick's magnificent “Biological Universe”). The weight of evidence obviously tells otherwise.
• The Ancient astronauts speculations of Agrest, von Daniken and others belong to this class as well.
• The zoo hypothesis of Ball and the related interdict hypothesis of Fogg suggest that there is a uniform cultural policy for advanced extraterrestrial civilizations to avoid any form of contact (including having visible manifestations) with the newcomers to the Galactic Club. The reasons behind such behavior may be those of ethics, prudence or practicality. In each case, these do not really offer testable predictions (if the extraterrestrial civilizations are sufficiently powerful, as suggested by the difference in ages of the Earth and the median of the set of earthlike planets) for which they have been criticized by Sagan, Webb and others. As a consequence, a 'leaky' interdict scenario is occasionally invoked to connect with the alleged extraterrestrial origin of UFOs, which is clearly problematic.
• The directed panspermia hypothesis of Crick and Orgel, proposed in 1973, supposes that the Earth has indeed been visited in a distant past with very obvious consequence – namely the existence of life on our planet! Those two famous biochemists proposed – partly tongue-in-cheek, but partly to point out the real problems with the then theories of biogenesis – that our planet has been intentionally seeded with microorganisms originating elsewhere. In other words, we are aliens ourselves! It is very hard to see how could ever hope to test the hypothesis of directed panspermia.
• The planetarium hypothesis of Stephen Baxter suggests that our astronomical observations do not represent reality, but a form of illusion, created by an advanced technological civilization capable of manipulating matter and energy on interstellar or Galactic scales.
• The simulation hypothesis of Nick Bostrom, although motivated by entirely different reasons and formulated in a way which seemingly has nothing to do with FP, offers a framework in which FP can be naturally explained. Bostrom offers a Bayesian argument why we might rationally think we live in a computer simulation of an advanced technological civilization inhabiting the "real" universe. This kind of argument has a long philosophical tradition, going back at least to Descartes' celebrated second Meditation, discussing the level of confidence we should have about our empirical knowledge. Novel points in Bostrom's presentation include the invocation of Moore's Law for suggesting that we might be technologically closer to the required level of computing sophistication than we usually think, as well as adding a Bayesian conditioning on the number (or sufficiently generalized "cost") of such "ancestor-simulations", as he dubs them. It is trivial to see how FP is answered under this hypothesis: extraterrestrial civilizations are likely to be simply beyond the scope of the simulation in the same manner as, for example, the present-day simulation of the internal structure of the Sun neglects the existence of other stars in the universe.

It is difficult to objectively assess the value of solipsist hypotheses as solutions to FP. Most of them are either untestable in principle, or testable only in consideration of very long temporal and spatial scales; they do not belong to the realm of science as it is conventionally understood.

In other words, they violate a sort of naive realism which underlies practically the entire scientific endeavor. Their proponents are likely to retort that the issue is sufficiently distinct from other scientific problems to justify greater divergence of epistemological attitudes – but this is rather hard to justify when one could still pay a smaller price. For instance, one could choose to abandon Copernicanism, like the Rare Earth theorists (although it might be particularly unpopular this year!) or – as I personally prefer – one might abandon gradualism (which has been thoroughly discredited in geo- and planetary sciences anyway) and end up with a sort of neocatastrophic hypothesis, like the phase-transition scenario.

Some of them, but not all, solipsist solutions violate the classical non-exclusivity (or “hardness”) requirement as well; in other words, they require an uncanny degree of cultural uniformity among the advanced technological civilizations. This is, for instance, obvious in zoo, interdict or planetarium scenarios, since they presume a large-scale cultural uniformity to maintain the isolation of either just us or any other Galactic newcomers, which is sufficiently improbable a priori.

This is not the case, however, with the simulation hypothesis, since the simulated reality is likely to be clearly designed and spatially and temporally limited. The directed panspermia has some additional problems – notably the absence of any further manifestations of our 'parent civilization', in spite of its immense age. If they became extinct in the meantime, what happened with other seeded planets (not to mention long-term astroengineering artifacts)? The Copernican reasoning suggests that we should expect evolution to occur faster at some places than on Earth (and, of course, slower at other sites as well); where are our interstellar siblings, then?

Usually, these hypotheses are mentioned (if at all) mostly for the sake of logical completeness, since they are in any case the council of despair. If and when all other avenues of research are exhausted, the conventional wisdom says, we could always turn toward these hypotheses. And, strangely enough, the conventional wisdom does seem on target here. Still, this neither means that they are all of equal value nor it should mislead us into thinking that they are necessarily improbable for the reason of desperation alone.

Bostrom's simulation hypothesis might, indeed, be quite probable, given some additional assumptions related to the increase in our computing power and decrease of information-processing cost. Directed panspermia could, in principle, get a strong boost if, for instance, the efforts of NASA and other human agencies aimed at preventing planetary contamination turn out to be unsuccessful. Finally, solipsist hypotheses need not worry about evolutionary contingency or generic probabilities of biogenesis or noogenesis, unlike practically all other proposed FP solutions.

Milan M. Cirkovic

SETI's Seth Shostak: Alien hunter

Seth Shostak is borderline absurd in this video. Bigger than a bread box? Jeez, SETI is 1) in serious denial about its chances of detecting extraterrestrial signals and 2) still about 20 to 30 years behind the times.

Now, to be fair, I know that Shostak knows better. He has said,

SETI searches are agnostic when it comes to the biochemistry of the aliens. After all, from our point of view, what makes them “intelligent” is their ability to build a radio transmitter or a powerful laser. The details of their construction are of no consequence for the search — except insofar as they might not be living on planets surrounding an ordinary star. If they are machine intelligence, they may have migrated away from their natal solar system, and of course that WOULD affect our search strategies.

Okay, then let's talk about those strategies. Dysonian SETI, perhaps? Scanning the outer galaxial rim for alternative habitable zones?

Shame that Shostak has to cloud SETI in the baggage of antiquated expectations of Spielbergesque visitors from another planet. Remember: Shostak's job is not to find signs of ETI, but to secure funding for SETI. Talk of post-Singularity colonization waves isn't likely going to win over converts...

The 'Rare Earth' delusion

In my experience, the most common solution given to the Fermi Paradox is the Rare Earth hypothesis -- the idea that life in the Galaxy is exceptionally rare and that planets like ours are freakishly uncommon. For many, this conveniently explains why we haven't been visited by little green men. Or more accurately, extraterrestrial machine intelligences.

I've always thought, however, that given cosmologically large numbers that this sort of thinking is symptomatic of our small minds and limited imaginations. It's easy for us to throw up our hands and sheepishly declare that we're somehow special. Such a conclusion, however, needs to be qualified against the data involved, and by the mounting evidence in support of the notion that ours appears to be a life-friendly universe.

What Do You Mean, 'Rare'?

Let's pause for a moment and look at the numbers.

Recent figures place the total number of stars in the Milky way at an astounding three trillion. I don't need to tell you that that is a huge number. But given how poor the human mind is at groking large figures I'm going to play with this number for a bit:

• 3 trillion fully expressed is 3,000,000,000,000 (12 zeros)
  
• As an exponent it can be expressed as 3 x 10¹²
• Re-phrased, it is 3 thousand billions, or 3 million millions

Which necessarily leads to this question: given such a ginormous figure, what does it mean to be rare?

Even if the Earth is a one in a million occurrence, that means there are still 3 million Earthlike planets in the Galaxy (assuming one Earthlike planet per star). Does that qualify as rare? Not in my books.

If, on the other hand, the Earth is a one in a billion occurrence, then there are only 3,000 Earths in the galaxy. That sounds a bit more rare to me -- but one in a billion!? Seriously?

We also have to remember that the 3 trillion stars only accounts for what exists right now in the Milky Way. There have been well over a billion trillion stars in our past Universe. As Charles Lineweaver has noted, planets began forming in our Galaxy as long as 9 billion years ago. We are relative newcomers to the Galaxy.

Our Biophilic Universe

But all this numerological speculation might be moot. We're overlooking the mounting evidence indicating that we live in a universe exceedingly friendly to life. What we see in the physical laws and condition of the universe runs contrary to the expectations of the Rare Earthers.

Indeed, we are discovering that the Galaxy is littered with planets. Scientists have already cataloged 321 extrasolar planets -- a number that increases by a factor of 60 with each passing year. Yes, many of these are are so-called "hot Jupiters," but the possibility that their satellites could be habitable cannot be ruled out. Many of these systems have stable circumstellar habitable zones.

And shockingly, the first Earthlike planet was discovered in 2007 orbiting the red star Gilese 581. It's only 20 light-years away, 1.5 times the diameter of Earth, is suspected to have water and an atmosphere, and its temperature fluctuates between 0 and 40 degrees Celsius.

If we are one in a billion, then, and considering that there are only 0.004 stars per cubic light-year, what are the odds that another Earthlike planet is a mere 20 light-years away?

Indeed, given all this evidence, the Rare Earthers are starting to come under attack. Leading the charge these days is Alan Boss who recently published, The Crowded Universe. Boss estimates that there may be billions of Earthlike planets in the Milky Way alone. "I make the argument throughout the book that we already know that Earths are likely to be incredibly common—every solar-type star probably has a few Earth-like planets, or something very close to it," says Boss. "To my mind, at least, if one has so many habitable worlds sitting around for five billion or 10 billion years, it's almost inevitable that something's going to start growing on the majority of them."

Life Abounds

And it gets worse for the Rare Earthers. They also have to contend with the conclusions of astrobiologists.

It's a myth, for example, that it took life a long time to get going on Earth. In reality it was quite the oppoite. Our planet formed over 4.6 billion years ago and rocks began to appear many millions of years later. Life emerged relatively quickly thereafter some 600 million years after the formation of rocks. It's almost as if life couldn't wait to get going once the conditions were right.

We also live in a highly fertile Galaxy that's friendly to extremophiles. The Panspermia hypothesis suggests that 'life seeds' have been strewn throughout the Galaxy; evidence exists that some grains of material on Earth have come from beyond our solar system.

Recent experiments have shown that microorganisms can survive dormancy for long periods of time and under space conditions. We also now know that rocks can travel from Mars to Earth and that simple life is much more resilient to environmental stress than previously imagined. Consequently, biological diversity is probably much larger than conventionally assumed.

Common Earth

My feeling is that the Rare Earth hypothesis is a passing scientific fad. There's simply too much evidence growing against it.

In fact, the only thing going for it is the Fermi Paradox. It's comforting to think that the Great Silence can be answered by the claim that we're exceptionally special. Rare Earth steers us away from other, more disturbing solutions --namely the Great Filter hypothesis.

But such is the nature of scientific inquiry. We're not always going to like what we find, even if it is the truth.

As for the Fermi Paradox, we'll have to look for answers elsewhere.

Freeman Dyson at TED: We can look for life in the outer solar system

Renowned theoretical physicist Freeman Dyson suggests that we can look for life on the moons of Jupiter and out past Neptune, in the Kuiper belt and the Oort cloud. He talks about what such life would be like (e.g. creatures that look like lenses and mirrors with roots that go deep into the ocean) and how we might find them.


Dyson is one of my favorite people in the whole world -- one of the great minds of our time. I'm overjoyed that he's still going strong well into his 80's.

Larger Milky Way has implications for the Drake Equation and the Great Silence -- or does it?

Apropos of Russell Blackford's recent posts about the Fermi Paradox, it should be mentioned that the Milky Way is 50% larger than previously thought. This will likely have implications to our appreciation of the Drake Equation and the Fermi Paradox.

What tipped cosmologists off was the discovery that our galaxy is spinning 15% faster than formerly assumed. The lead researcher on the project, Mark Reid of the Harvard-Smithsonian Center for Astrophysics in Cambridge, estimates that the Milky Way's spin is about 914,000 km/hour, significantly higher than the widely accepted value of 792,000 km/hour.

The only thing that could account for this increased spin rate was more mass -- a lot more mass. As a result of Reid's findings, our models now need to account for a galaxy that is 50% heavier, 15% wider and contains a mind-boggling 3 trillion stars! That is an astounding 750% increase from 400 billion.

You might want to pause for a moment and think about this.

This is remarkable news and the implications of these findings are going to take a while to sink in. My first reaction was to consider the implications to the Fermi Paradox. Does a significantly larger Milky Way accentuate or diminish the problem that is the Great Silence?

First off, it throws previous Drake Equation estimates out the window. Blogger Paul Hughes has already crunched some numbers and has come up with his own estimate: he believes there may be as many as 12 billion Earth-like planets in our galaxy capable of supporting liquid water and in turn carbon-based life as we know it (Hughes doesn't take the equation beyond that as he was inquiring into the number of potentially habitable planets).

But as many of my readers know, I'm not a great fan of the Drake Equation to begin with. It's in dire need of an upgrade and it completely fails to account for the cosmological development of the galaxy and other temporal aspects. That said, it's safe to assume that the probability of extraterrestrial life emerging in the Galaxy is now significantly higher than it was before -- both in the Galaxy's long history and now.

Second, the new and improved Milky Way throws off previous calculations as to how long it would take an advanced civilization to inhabit all four corners of the galaxy. An extraterrestrial migration wave would likely be comprised of self-replicating colonization probes that spread out across the galaxy at an exponentially increasing rate. Previous estimates placed complete Galaxy-wide colonization at a few million years. Given that we were wrong about the size of the Milky Way and the number of stars, we have to conclude that it would take longer to colonize the entire galaxy.

Just how much longer I'm not sure [sounds like a future project in the making], but given that we're talking about exponentially increasing migration rates I would have to think that we are not talking about an order of magnitude. And even if it does take significantly longer, we still have to take the extreme age of the Milky Way into consideration and the likelihood that intelligence may have emerged in the Galaxy as long as 4.5 billion years ago. The age of the Galaxy is still disproportionately longer than even the most pessimistic colonization rate estimates.

What does all this mean?

Well, nothing really. The Great Silence is obviously still in effect and something's still screwy with the Universe. A bigger Milky Way means that there's likely more intelligent life in the Galaxy than we had previously assumed, but that interstellar colonization and communication rates are slightly longer.

The Fermi Paradox lives on.

Guest Blogger: Russell Blackford: Where's my alien civilisation? Part 2.

Where were we?

This year we have Darwin's 200th birthday and the 150th anniversary of the publication of On the Origin of Species. It's a natural time for thoughts to turn to issues about the origins of life and the trajectory of biological evolution. It was in that context that I found myself, this week, thinking again about the Fermi paradox and the mysteries of the Drake equation, after some discussion of these over on Richard Dawkins' site. The discussion on Dawkins' site got a bit acrimonious, for some reason, but I'm sure we can avoid that here.

At the end of Part 1., I left the Fermi paradox with questions about the fate of technological civilisations. Do they self-destruct? Do they become unrecognisable to us? Or does the rate of technological progress flatten out, in which case we are not approaching a technological singularity – rather, we are somewhere on the steep part of a sigmoid curve.

Deeper into Drake's equation

I suspect that the evidence that we're on a sigmoid curve is pretty much illusory. E.g., the evidence from science fiction is probably just evidence of limits to our imaginative capacities. Still, it's not a scenario that can be ruled out (and it seems just as possible to me as the technological singularity scenario). It's certainly conceivable that at least some kinds of technological progress flatten out. At 1 per cent of the speed of light it would take us over 400 years to reach the nearest stars. We don't know how much longer to reach the nearest worlds that could easily be colonised. We tend to think that the problems will be solved in millions of years of future progress, but we may not be good at working out what problems can and cannot be solved, at least easily enough to be worth the effort, even over very long tracts of time.

That said, I'd prefer to look for an explanation deeper in the Drake equation, which uses several variables to calculate the number of technologically advanced species in our galaxy. The variables include the average rate of star formation, the fraction of stars that have planets, the fraction of planets that can potentially support life, the fraction of these that actually develop life, the fraction of these where intelligent life evolves, the fraction of these that develop civilisations that send detectable signs of themselves into space, and the length of time that such civilisations exist.

Some of the fractions that feed into the Drake equation may be very small indeed, so small as to make technologically advanced species, and the civilisations they create, incredibly rare. It's consistent with what we now know that the conditions required for life to form are extremely fortuitous and unusual. It may need very rare combinations of environmental factors. And even then, you can have life staying at levels of neurological complexity that don't lead to technology.

We know that life can stay at levels of intelligence well below our own pretty much indefinitely. If not for one or more catastrophic events at the end of the Cretaceous Period, including the bolide impact that caused the Chicxulub Crater, Earth might still be dominated by dinosaurs, which might not have developed any impressive levels of intelligence. They hadn't done so in the previous 150-odd million years, so there's no reason to think they would have in the past 65 million years.

We really need to know a lot more, and we soon reach a point where people are relying on nothing more than hunches. With that disclaimer, my hunch is that the evolution of a technological civilisation to our sort of level or beyond is a statistically improbable event. I.e., it is an event that takes place quite infrequently in an average galaxy. I can't be much more precise about what "quite infrequently" means, except to say that I wouldn't be at all surprised if human beings were the only species in our galaxy to have created technological civilisations.

There's a lot of things we'd need to know before we could say anything more confidently, or more precise, than that. E.g., we'd need a well-corroborated theory of the origin of life to give us an idea of how rare the conditions for it really are. We just don't have one. We have a well-corroborated theory of how life diversifies - neo-Darwinian evolutionary biology - but not of how it gets started. The best we have is an idea of what sort of theory would be a workable account of abiogenesis – some kind of theory of early kinds of self-replicating molecules that were able to develop into the building blocks for the kinds of life forms from which we, and the rest of contemporary life on Earth, all eventually diversified.

There are so many unknowns about all this that I think we're a long way from being able to deduce any pessimistic conclusions about humanity's future. Even if life itself is more common in the universe than appears so far, the evolution of human-level intelligence might be very rare indeed. Even if technological change ends up following a sigmoid curve, we don't know how to unpack the detail of that – it might mean that space travel at appreciable fractions of the speed of light is going to turn out more difficult than we commonly assume … but, for all that, our ability to transform our capacities may reach levels far beyond what is current. We can't predict the future, though we can forecast and consider various possibilities and scenarios.

Still waiting

Meanwhile, I'm still waiting for my alien civilisation. I'm also waiting for my jet car. If it doesn't turn up before I shuffle off this mortal coil, I don't know if that's a reason for pessimism or optimism.

Where has the damn thing gone?


Russell Blackford is an Australian philosopher. He has published extensively (novels, short stories, academic monographs and articles, and book reviews) and is editor-in-chief of The Journal of Evolution and Technology. His home blog is Metamagician and the Hellfire Club.

Guest Blogger: Russell Blackford: Where's my alien civilisation? Part 1.

Fermi's paradox

I'm sure my readers are familiar with Fermi's paradox. Some of you may even feel it's debated to death lately, but in this great memorial year (Darwin's 200th birthday, among other things) we'll be hearing a lot more about the origins of life and the trajectory of evolution. Fermi's paradox connects with all that, and I'll get to the connection in Part 2.

Here's a quick refresher. Enrico Fermi observed that there seems to be a contradiction between the fact that we have not encountered alien civilisations and facts about the scale of the universe (and, indeed, our own galaxy). The vastness of space, the enormous number of stars and planets, and the age of the stars all add up to a presumption that there should be plenty of life Out There, some of it much older than life on Earth. If there are intelligent beings in space that began with millions of years of head start over us, why don't they have technological civilisations far more advanced than our own? But if they do, why have we never encountered such things as alien space craft, probes, or radio signals?

Colonising the galaxy

Consider that the diameter of the galaxy is about 100,000 light years. Imagine for the sake of argument that there's a technological civilisation somewhere near the galactic centre. Then imagine that it has the capacity to send out space ships or self-replicating probes or similar devices at even 1 per cent of the speed of light. It could get a ship or a probe out to the galactic rim in something like five million years.

If the alien civilisation sends out a few ships every thousand years, they will soon mount up in numbers. Over a few million years, it could send out many thousands of ships. If the colonies founded by those ships themselves got in on the act and sent out ships of their own, and the colonies they founded sent out ships, we get ourselves an exponential increase.

It looks as if a sufficiently advanced and determined civilisation could colonise the galaxy, to a greater or lesser level of density, in "only" a few million years (a tiny amount of time in geological or astrophysical terms). Perhaps not all advanced technological civilisations have that ambition, but it would only take one that has the ambition plus a few million years' start on us, and the galaxy should be widely colonised by now – at least to some density level that we’d notice. Where are the space craft, the probes, the signals, maybe even the astrophysical engineering projects?

There seems to be good evidence that the galaxy doesn't contain even one civilisation that is old enough, advanced enough, and determined enough. So, why?

You might think that if the evolution of technological civilisations were a common event in the universe, there'd be at least one civilisation like this somewhere in the galaxy, with its billions of stars. Even if it started out on the distant rim, far away from us on the other side, that's just going to make it take a few million more years to reach us. So allow ten million years of head start – that's still nothing in the kind of timeframe we're talking about. If technological civilisations are commonplace, there should be some that are those millions of years ahead of us (and some will come along behind us, trailing by a few million years).

So, where are they?

Might it be that creating space craft that can travel reliably at even 1 per cent of the speed of light is harder than we assume? Or maybe advanced technological civilisations tend to destroy themselves? Or do they tend to stop expanding their populations, as human beings are doing? We're really guessing.

The most pessimistic solution is that they tend to destroy themselves. From the point of view of our own species, that solution would suggest that our self-destuction lies ahead. If we discover life elsewhere, then, it's bad news: the more common life is, the more common technological civilisations should be, and hence the more likely it is that the reason we don't see them is that they destroy themselves. QED.

But I don't think that's the best way to look at it. There are other possibilities. Perhaps technological civilisations tend to reach a technological singularity point, at which stage they are transformed so comprehensively and deeply that we wouldn't even recognise them. They might miniaturise themselves in some way that makes expansion into space pointless, or they might switch over to some kind of substrate that we would never recognise as a form of life (partly, no doubt, for their own convenience, but perhaps partly to avoid interfering with vulnerable civilisations at our level).

Another possibility – one that might bother my transhumanist friends almost as much as the self-destruction account – is that the rate of advance of technology does not accelerate to a singularity. I.e., the mathematical relationship between time and technological capacity may not be an exponential function . Perhaps it will turn out that we are now somewhere on the relatively steep part of a sigmoid curve. In that case, perhaps advanced technological civilisations never obtain the level of technological capacity that enables them to go out and colonise galaxies. Maybe there are hard limits to what is possible, or perhaps there are universal limits to desire. If this is the correct picture, transhumanists should be disappointed – what lies ahead for the human species may not be anywhere near as radical as they hope.

The sigmoid curve interpretation has a kind of intuitive rightness about it (which doesn't mean it's correct). First, when science fiction writers describe the future they tend to imagine reaching some higher technological level and things then going on without huge change for millions of years. But of course the content of science fiction might just be evidence of limits to our current imaginative capacities.

We might also be impressed by the now-embarrassing question, "Dude, where's my jet car?" It sometimes seems that, even as the power of computer hardware continues to follow Moore's Law, progress in what we can actually do with it seems to be slowing down. "Where's my robot maid?" If so, human technological potential may be limited, and we need to imagine the future of the world with bounded horizons. Not that that need lead to crippling pessimism – it would not demonstrate our inability to produce great advances in, say, health and life span. What is and is not possible may be different from what we intuit in advance.

I think, though, that there's another way to look at this. I'll be back in a few hours to go deeper into the Drake equation.


Russell Blackford is an Australian philosopher. He has published extensively (novels, short stories, academic monographs and articles, and book reviews) and is editor-in-chief of The Journal of Evolution and Technology. His home blog is Metamagician and the Hellfire Club.

Could ET be sending messages by tweaking variable stars?

From the Nature article, 'Galactic internet' proposed:

Just by gazing at the stars, earthling astronomers might have unwittingly picked up broadcasts from extraterrestrial civilizations. So says a neutrino physicist, adding that it might take researchers just a few months of searching to find evidence of this alien internet.

John Learned at the University of Hawaii in Honolulu and his colleagues think that signals could be sent by manipulating Cepheid variable stars. These rare stars can be seen in other galaxies more than 60 million light years from our own.

Cepheids dim and brighten regularly, in a pattern that depends on their brightness. This lets astronomers measure the distance to the stars, helping to resolve mysteries such as the Universe's age and how fast it is expanding. As such, any sufficiently advanced civilization would want to monitor such stars, the scientists reasoned.

To send messages using a Cepheid, Learned and his colleagues suggest that extraterrestrials might change the star's cycle. A Cepheid becomes dimmer as ionized helium builds up in its atmosphere. Eventually, the atmosphere expands and deionizes, restarting the cycle.

More.

Latest podcast posted: 2008.04.01

The latest episode of the Sentient Developments Podcast is now available. Alternative audio formats are also available.

This episode:

Considering the Hadron Particle Accelerator and asking the question: When is an existential risk TOO risky?

What the Fermi Paradox tells us about humanity's future: Making claims about what advanced civilizations DO NOT do.

Christopher Hitchens gets it wrong about Buddhism.

Latest podcast posted: 2008.03.11

The latest episode of the Sentient Developments Podcast is now available. Alternative audio formats are also available.

In this episode I discuss seven ways to control the Galaxy with self-replicating probes, the problem with 99.9 % of so-called 'solutions' to the Fermi Paradox, and why we should work to overcome gender.

Centauri Dreams on Active SETI

The METI debate (Messages to Extra Terrestrial Intelligences) and the recent Grinspoon article is being discussed over at Centauri Dreams.

Grinspoon: Who Speaks for Earth?

There's a provocative new article by David Grinspoon, author of Lonely Planets, about the METI debate in SEED Magazine:

After decades of searching, scientists have found no trace of extraterrestrial intelligence. Now, some of them hope to make contact by broadcasting messages to the stars. Are we prepared for an answer?

Excerpt:

Zaitsev has already sent several powerful messages to nearby, sun-like stars—a practice called "Active SETI." But some scientists feel that he's not only acting out of turn, but also independently speaking for everyone on the entire planet. Moreover, they believe there are possible dangers we may unleash by announcing ourselves to the unknown darkness, and if anyone plans to transmit messages from Earth, they want the rest of the world to be involved. For years the debate over Active SETI versus passive "listening" has mostly been confined to SETI insiders. But late last year the controversy boiled over into public view after the journal Nature published an editorial scolding the SETI community for failing to conduct an open discussion on the remote, but real, risks of unregulated signals to the stars. And in September, two major figures resigned from an elite SETI study group in protest. All this despite the fact that SETI's ongoing quest has so far been largely fruitless. For Active SETI's critics, the potential for alerting dangerous or malevolent entities to our presence is enough to justify their concern.

Interesting quote by Michael Michaud, a former top diplomat within the US State Department and a specialist in technology policy: "Active SETI is not science; it's diplomacy. My personal goal is not to stop all transmissions, but to get the discussion out of a small group of elites."

More on this debate here and here.

Astrosociobiology article on Wikipedia deleted

The astrosociobiology page on Wikipedia has been deleted. For the sake of posterity, I present its final incarnation here:

Astrosociobiology

Astrosociobiology (also referred to as exosociobiology, extraterrestrial intelligence (ETI), and xenosociology) is the speculative scientific study of extraterrestrial civilizations and their possible social characteristics and developmental tendencies. The field involves the convergence of astrobiology, sociobiology and evolutionary biology. Hypothesized comparisons between human civilizations and those of extraterrestrials are frequently posited, placing the human situation in the same context as other extraterrestrial intelligences. Whenever possible, astrosociobiologists describe only those social characteristics that are thought to be common (or highly probable) to all civilizations. Since no extraterrestrial civilizations have ever been studied, the subject is entirely hypothetical and necessarily self-referential.

Contents

1 Methodologies
2 Assumptions
2.1 Possible unique aspects of Earth life
2.2 Counter-argument: abundance of alternative sources
3 Possible extraterrestrial characteristics
4 Civilization types
5 Notable astrosociobiologists
6 See also
7 References
8 External links

Methodologies

Sociobiology attempts to explain animal behavior, group behavior and social structure in terms of evolutionary advantage or strategy and using techniques from ethology, evolution and population genetics. Sociobiologists are especially interested in comparative analyses, particularly in studying human social institutions and culture.

Astrobiology is the speculative field within biology that considers the possible varieties and characteristics of extraterrestrial life. Astrobiologists speculate about the possible ways that organic life could come into being in the universe and the potential for artificial and postbiological life.

Astrosociobiologists, like evolutionary biologists and sociobiologists, are concerned with the phenomenon of convergent evolution, the evolutionary process in which organisms not closely related independently acquire some characteristic or characteristics in common, usually (but not necessarily) a reflection of similar responses to similar environmental conditions. Examples include physical traits that have evolved independently (e.g. the eye), ecological niches (e.g. pack predators), and even technological innovations (e.g. language, writing, the domestication of plants and animals, and basic tools and weapons). Astrosociobiologists take the potential for convergent evolution off-planet and speculate that certain ecological and sociological niches may not be Earth-specific or human-specific and are archetypal throughout the universe.

However, there may be limits to this kind of speculation, particularly if there is a dearth of comparable habitats to our own across the galaxy. Some thinkers, while acknowledging that biological and social evolution may follow similar patterns across the universe, also note the problem of evidence and the absence of extraterrestrial contact. Simon Conway Morris, in his book, Inevitable Humans in a Lonely Universe, notes life's "eerie" ability to repeatedly navigate to a single solution. "Eyes, brains, tools, even culture: all are very much on the cards," he writes. "So if these are all evolutionary inevitabilities, where are our counterparts across the galaxy? The tape of life can only run on a suitable planet, and it seems that such Earth-like planets may be much rarer than hoped. Inevitable humans, yes, but in a lonely Universe."[1]

Assumptions

In order for astrosociobiologists to embark on speculations about the condition and characteristics of extraterrestrial civilizations, a number of assumptions are necessarily invoked:

1. Extraterrestrial civilizations exist
2. Extraterrestrial civilizations operate in agreement with the known laws of physics
3. Extraterrestrial civilizations must in some part resemble our own, both in terms of: a) morphological and psychological characteristics, and b) civilizational traits and tendenciesIn other words, astrosociobiologists assume that intelligent life arises from similar environmental conditions and similar evolutionary processes as humanity.

It is currently difficult to tell if these are valid assumptions. For example, the Rare Earth hypothesis and the Fermi Paradox suggests that we might be alone in the galaxy. It's also conceivable that aliens and their civilizations may scarcely resemble our own. Astrosociobiology also involves a fair degree of environmental determinism. Astrosociobiologists counterargue that all of these points can be countered by the Copernican principle and the self-sampling assumption (a variant of the anthropic principle). We shouldn't assume, they argue, that we're unique and we should start from the premise that we are very typical.

Possible unique aspects of Earth life

It is possible that the unique conditions on Earth allow for specific technologies to develop which would take many times longer for a civilization not having these conditions to achieve. The list of possibly unique conditions on Earth, and of related discoveries, is quite long. Some examples:

* The Hall-Héroult process and the Bayer process, if not discovered in the late 19th Century, might have led to a delay in the creation of aluminium-dependent technologies, such as aircraft and rocketry.
* The Moon produces tides, and offers some protection from asteroids, comets, and radiation. [2]
* Many discoveries were essentially accidental, such as the discovery of penicillin. Others were based on a theoretical insight, such as the transistor.

It is possible that the conditions for the creation of hydrocarbons, coal, or natural gas would not exist on other planets. These fuels were essential for us to move past dependence upon wood and animal based energy systems. Although waterwheel, wind, and solar energy technologies existed, they were not developed further until suitable industrial techniques were found to produce better materials. These techniques consume massive amounts of energy, and therefore could not be powered by the unimproved technologies. A similar argument could be made that without fossil fuel technologies, more powerful technologies, such as nuclear reactors, could not develop.

Counter-argument: abundance of alternative sources

Human perception has a natural bias towards the known energy development paths of Human civilization. It must also be noted that during both the 1973 energy crisis and the 1979 energy crisis highly industrialized societies continued to function; many moved towards developing alternative energy technologies on a massive scale under the assumption that these could provide the energy needed to continue industrial and commercial processes should fossil fuel supplies be compromised in some critical way.

Given this development, it is possible that a society could develop without a stage where fossil fuel based energy production occurs. This version of Buckminster Fuller's argument on current solar income conforms with Paul Hawken's idea of restorative economy, stating that fossil fuel based energy production is not essential nor desirable given the effects and alternatives.

Possible extraterrestrial characteristics

Given these assumptions, astrosociobiologists attempt to make predictions about those characteristics that may be common to all extraterrestrial societies. For example, based on human experience, astrosociobiologists conclude very broadly that all civilizations go through similar developmental stages, including stone age and agrarian culture, industrialization, globalization, and an information age. Similar assumptions are made about the development of technological innovations (universal technological archetypes) and scientific breakthroughs (including the rough chronological order in which these advancements are developed). The possibility also exists for the existence of common cultural and meta-ethical characteristics of advanced societies (i.e. the notion that advanced societies will independently reach the same conclusions about ethics, morality and social imperatives).

Astrosociobiologists also theorize about the existence of developmental mechanisms that constrain and give directionality to the evolution of organisms and society itself. One such guiding evolutionary force is the notion of the megatrajectory. Posited by A. H. Knoll and R. K. Bambach in their 2000 collaboration, "Directionality in the History of Life," Knoll and Bamback argue that, in consideration of the problem of progress in evolutionary history, a middle road that encompasses both contingent and convergent features of biological evolution may be attainable through the idea of the megatrajectory:

We believe that six broad megatrajectories capture the essence of vectoral change in the history of life. The megatrajectories for a logical sequence dictated by the necessity for complexity level N to exist before N+1 can evolve...In the view offered here, each megatrajectory adds new and qualitatively distinct dimensions to the way life utilizes ecospace. – [3]

According to Knoll and Bambach, the six megatrajectories outlined by biological evolution thus far are:

1. the origin of life to the "Last Common Ancestor"
2. prokaryote diversification
3. unicellular eukaryote diversification
4. multicellular organisms
5. land organisms
6. appearance of intelligence and technology

Some astrosociobiologists, such as Milan Ćirković and Robert J. Bradbury, have taken the megatrajectory concept one step further by theorizing that a seventh megatrajectory exists: postbiological evolution triggered by the emergence of artificial intelligence at least equivalent to the biologically-evolved one, as well as the invention of several key technologies of the similar level of complexity and environmental impact, such as molecular nanoassembling or stellar uplifting.

Along similar lines, historian of science Steven J. Dick, in his 2003 paper "Cultural Evolution, the Postbiological Universe and SETI," posited a central concept of cultural evolution he called the Intelligence Principle:

The maintenance, improvement and perpetuation of knowledge and intelligence is the central driving force of cultural evolution, and that to the extent intelligence can be improved, it will be improved. [– [4]]

It is through the application of this principle, argues Dick, that speculations about the developmental tendencies of advanced civilizations can be made.

The difficultly of engaging in such speculation, however, is that it is highly theoretical; there is very little empirical evidence. Moreover, humanity hasn't progressed through these later developmental stages. Astrosociobiologists currently have no data to support the idea that human civilization will continue on into the foreseeable future. Indeed, in considering the Fermi Paradox, scientists may actually have a data point suggesting a limitation to how far advanced civilizations can develop.

However, with each advancing step that the human species takes, astrosociobiologists will assume that extraterrestrials--both past and present –will have gone through similar stages.

Civilization types

A method for classifying civilization types was introduced by Russian astronomer Nikolai Kardashev in 1964. Known as the Kardashev scale, classifications are assigned based on the amount of usable energy a civilization has at its disposal and increasing logarithmically:

* Type I - A civilization that is able to harness all of the power available on a single planet, approximately 1016W.
* Type II - A civilization that is able to harness all of the power available from a single star, approximately 1026W.
* Type III - A civilization that is able to harness all of the power available from a single galaxy, approximately 1036W.

Human civilization has yet to achieve full Type I status, as it is able to harness only a portion of the energy that is available on Earth. Carl Sagan speculated that humanity's current civilization type is around 0.7.

Notable astrosociobiologists

• Frank Drake
• Freeman Dyson
• Nikolai Kardashev
• Carl Sagan
• Frank Tipler

See also

• Allen Telescope Array
• Astrolinguistics
• Drake equation
• Exobiology
• Fermi Paradox
• Interstellar Responsibility Quarantine
• SETI
• S.W.A.G.
• Sociobiology
• Technological Singularity
• Transhumanism

References

1. ^ Morris, Simon Conway (2004). Life's Solution: Inevitable Humans in a Lonely Universe. Cambridge University Press. ISBN 0-521-60325-0.
2. ^ Comins, Neil F. (1995). What if the Moon Didn't Exist?: Voyages to Earths That Might Have Been. Harper Perennial. ISBN 0-06-092556-6.
3. ^ Knoll, A. H.; R. K. Bambach (2000). "Directionality in the history of life: diffusion from the left wall or repeated scaling of the right". Paleobiology 26 (4): 1-14.
4. ^ Dick, Steven J. (2003). "Cultural Evolution, the Postbiological Universe and SETI". International Journal of Astrobiology 2: 65-74.

External links

• Astrobiology Magazine
• Astrobiology Web
• SETI Institute

Brin's position on the METI issue clarified

Science fiction author and futurist David Brin recently contacted me about what he feels was my very poor interpretation of his stance on the METI issue.

David and I have since cleared things up via email, but for the sake of furthering this discussion I thought I'd reproduce parts of our conversation here.

From David,

[RE: Brin's article, "Shouting at the Cosmos: ...Or How SETI has Taken a Worrisome Turn Into Dangerous Territory."]

... you wrote: "Brin is vehemently opposed to this idea, as he believes it could put humanity in great peril. For all we know, he argues, some malevolent ETI is lurking in the neighborhood waiting for less advanced civilizations to draw attention to themselves."

I would be very interested in the provenance of this lurid and somewhat demeaning quasi-quotation.

My position is simply that narrowly dogmatic communities should not plunge into activities that commit humanity down paths that have low probability but high potential impact outcomes, without at least first engaging the wider world scientific community in eclectic discussion.

The only "vehemence" has been to ask for open discussions, which should be enjoyable and illuminating to all.

There is a general principle here. It is simply wrong to arrogate peremptory moves that bet human posterity, based upon cult-like and unchallenged assumptions.

It appears, much to my surprise, that I made incorrect inferences about his particular position as it pertains to the Active SETI approach and his motives for wanting to generate discussion. In my response to Brin I asked him to be more explicit in the future about what he is and is not saying. To which he responded,

The Lifeboat article, I thought, was clear enough, never once mentioning alien badguys, in any way shape or form, and repeatedly stating the goal of open discussion -- something that the small and increasingly cult-like SETI/METI community has strenuously avoided.

Comments welcome. I'd be curious to know how my readers have interpreted Brin's writings on the subject.