New theory may explain why radio SETI has failed

It's been nearly 50 years since scientists first started scanning the heavens for radio signals that would indicate the presence of intelligent extraterrestrial life. And in all those 50 years we haven't heard so much as a peep. The apparent failure of radio SETI thus far has provided much of the fuel that now powers the Fermi Paradox, the observation that we haven't encountered signs of ETI's when we probably should have by now.

But a new theory may explain part of the problem and why radio SETI has so far proved fruitless. Reginald Smith from the Bouchet-Franklin Institute in Rochester argues that there is a limit to how far a radio signal from ET can travel before it becomes too faint to hear. If true, this could have interesting ramifications for radio SETI and our expectations for the project.

In his article, "Broadcasting but not receiving: density dependence considerations for SETI signals,"Smith applies his idea to the Drake Equation and derives a minimum density of civilizations below which contact is improbable within a given volume of space. The calculation depends on factors such as the lifetime of a civilization and the distance that it might be possible to communicate via radio signals. His thesis has produced some interesting scenarios.

"Assuming the average communicating civilization has a lifetime of 1,000 years, ten times longer than Earth has been broadcasting, and has a signal horizon of 1,000 light-years, you need a minimum of over 300 communicating civilization in the galactic neighborhood to reach a minimum density," writes Smith.

Consequently, if there are less than 300 advanced civilizations in our galaxy, the chances are that they’ll never notice each other. And a figure of N being less than 300 is not out of the question given recent insights into cosmology, astrobiology and the rise of the Rare Earth Hypothesis.

Smith's theory has led some to suggest that the Fermi Paradox has been solved. But their thinking here is flawed.

Our (apparent) inability to detect radio signals does not wipe away other means for extraterrestrial communication (quantum communication schemes, Bracewell probes) or detection (Dysonian SETI, interstellar calling cards, etc.), nor does it answer the issue as to why the Galaxy hasn't been colonized by now (i.e. self-replicating Von Neuman colonization probes).

So, while Smith's theory may explain the failure of radio SETI, it doesn't erase the problem of the Great Silence.

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.

A year ago on SentDev: The Drake Equation is obsolete

Just say no to N = N* fp ne fl fi fc fL.

Copyright Lynette Cook
I'm surprised how often the Drake Equation is still mentioned when people discuss such things as the search for extra terrestrial intelligence (SETI), astrobiology and problems like the Fermi Paradox.

Fairly recent insights in such fields as cosmology, astrobiology and various future studies have changed our perception of the cosmos and the ways in which advanced life might develop.

Frank Drake's equation, which he developed back in 1961, leaves much to be desired in terms of what it's supposed to tell us about both the nature and predominance of extraterrestrial life in our Galaxy.

The Drake Equation

The Drake equation states that:

where:

N is the number of civilizations in our galaxy with which we might hope to be able to communicate and:

R* is the average rate of star formation in our galaxy
fp is the fraction of those stars that have planets
ne is the average number of planets that can potentially support life per star that has planets
fl is the fraction of the above that actually go on to develop life at some point
fi is the fraction of the above that actually go on to develop intelligent life
fc is the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
L is the length of time such civilizations release detectable signals into space.

Arbitrary at best

The integers that are plugged into this equation are often subject to wide interpretation and can differ significantly from scientist to scientist. Even the slightest change can result in vastly different answers. Part of the problem is that our understanding of cosmology and astrobiology is rapidly changing and there is often very little consensus among specialists as to what the variables might be.

Consequently, the Drake formula relies on 'stabs in the dark.' This makes it highly imprecise and unscientific. The margin of error is far beyond what should be considered acceptable or meaningful.

No accounting for cosmological development or time

Another major problem of the Drake Equation is that it does not account for two rather important variables: cosmological developmental phases and time (see Cirkovic, "The Temporal Aspect of the Drake Equation and SETI").

More specifically, it does not take into consideration such factors as the age of the Galaxy, the time at which intelligence first emerged, or the presence of physiochemical variables necessary for the presence of life (such as metallicity required to form planets). The equation assumes a sort of cosmological uniformity rather than a dynamic and ever changing universe.

For example, the equation asks us to guess the number of Earth-like planets, but it does not ask us when there were Earth-like planets. And intelligence itself may have been present as long as 2 to 4.5 billion years ago.

The Galaxy's extreme age and the potential for intelligence to have emerged at disparate points in time leaves an absurdly narrow window for detecting radio signals. The distances and time-scales in question are mind-boggingly vast. SETI, under its current model, is conducting an incredibly futile search.

Detecting ETI's

Which leads to the next problem, that of quantifying the number of radio emitting civilizations. I'm sure that back in the 1960's it made a lot of sense to think of radio capability as a fairly advanced and ubiquitous means of communication, and by consequence, an excellent way to detect the presence and frequency of extraterrestrial civilizations.

But time has proven this assumption wrong. Our radio window is quickly closing and it will only be a matter of time before Earth stops transmitting these types of signals -- at least unintentionally (active SETI is a proactive attempt to contact ETI's with radio signals).

Due to this revelation, the entire equation as a means to both classify and quantify certain types of civilizations becomes quite meaningless and arbitrary. At best, it's a way of searching for a very narrow class of civilizations under very specific and constrained conditions.

Rather, SETI should continue to redefine the ways in which ETI's could be detected. They should try to predict future means of communication (like quantum communication schemes) and ways to identify these signals. They should also look for artificial objects such as megascale engineering and artificial calling cards (see Arnold, "Transit Lightcurve Signatures of Artificial Objects").

The future of advanced intelligence

Although possibly outside the auspices of this discussion, the Drake Equation does not account for the presence of post-radio capable civilizations, particularly post-Singularity machine intelligences. This is a problem because of what these types of civilizations might be capable of.

The equation is used to determine the number of radio capable civilizations as they conduct their business on their home planet. Again, this is a vary narrow view of ETI's and the space of all possible advanced civilizational types. Moreover, it does not account for any migratory tendency that advanced civs may have.

The Drake Equation does not tell us about exponential civilizational growth on account of Von Neumann probe disbursement. It does not tell us where advanced ETI's may be dwelling or what they're up to (e.g. Are they outside the Galaxy? Do they live inside Jupiter Brains? Do they phase shift outside of what we regard as habitable space? etc.). This is a serious shortcoming because the answers to these questions should help us determine not just where we should be looking, but they can also provide us with insight as to the makeup of advanced intelligence life and our own potential trajectory.

In other words, post-Singularity ETI's may represent the most common mode of existence for late-stage civilizations. And that's who we should be looking for rather than radio transmitting civs.

Are we alone?

Michael Crichton once put out a very weak argument against the Drake Equation. He claimed that SETI was a religious endeavor because it was a search for imaginary entities. He is wrong, of course; we should most certainly search for data where we think we might find it. I believe, despite the low odds, that it is reasonable to assume that our search for life on other planets is warranted. Even a negative result can be meaningful.

Consequently, SETI should keep listening, but expect to hear nothing. If we should suddenly hear something from the depths of space, then we will have to seriously re-evaluate our assumptions.

At the same time we should find better ways to detect advanced life and tweak the Drake Equation in such a way as to account for the missing variables and factors I mentioned earlier.

Again, and more generally, we should probably adopt the contact pessimist's frame. Back in the 60's and 70's, when the contact optimists like Sagan, Shklovskii and Drake ruled the Earth, it was not uncommon to think that N in the equation fell somewhere between 10x6 to 10x9.

These days, in the post Tipler and Hart era of astrosociobiology, cosmologists and astrobiologists have to take such factors into consideration as Von Neumann probes, the Fermi Paradox, the Rare Earth Hypothesis, stronger variants of the anthropic principle and catastrophism.

Put another way, as we continue to search for advanced ETI's, and as we come to discover the absurdity of our isolation here on Earth, we may have no choice but to accept the hypothesis that advanced life does not venture out into space for whatever reason (the most likely being self-destruction).

Our other option is to cross our fingers and hope that something radical and completely unpredictable lies on the other side of the technological Singularity.

Latest audiocast posted: 2008.02.19

The latest Sentient Developments Podcast is now available. You can subscribe to this feed. Go here for alternative audio formats.

In this episode I discuss a conversation I had with Alcor's Tanya Jones, why the Drake Equation is obsolete, and Anonymous's war on Scientology.

Interactive Drake Equation

Space Radio: More Static, Less Talk.

The Drake Equation is obsolete

Copyright Lynette Cook

I'm surprised how often the Drake Equation is still mentioned when people discuss such things as the search for extra terrestrial intelligence (SETI), astrobiology and problems like the Fermi Paradox.

Fairly recent insights in such fields as cosmology, astrobiology and various future studies have changed our perception of the cosmos and the ways in which advanced life might develop.

Frank Drake's equation, which he developed back in 1961, leaves much to be desired in terms of what it's supposed to tell us about both the nature and predominance of extraterrestrial life in our Galaxy.

The Drake Equation

The Drake equation states that:

where:

N is the number of civilizations in our galaxy with which we might hope to be able to communicate and:

R* is the average rate of star formation in our galaxy
fp is the fraction of those stars that have planets
ne is the average number of planets that can potentially support life per star that has planets
fl is the fraction of the above that actually go on to develop life at some point
fi is the fraction of the above that actually go on to develop intelligent life
fc is the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
L is the length of time such civilizations release detectable signals into space.

Arbitrary at best

The integers that are plugged into this equation are often subject to wide interpretation and can differ significantly from scientist to scientist. Even the slightest change can result in vastly different answers. Part of the problem is that our understanding of cosmology and astrobiology is rapidly changing and there is often very little consensus among specialists as to what the variables might be.

Consequently, the Drake formula relies on 'stabs in the dark.' This makes it highly imprecise and unscientific. The margin of error is far beyond what should be considered acceptable or meaningful.

No accounting for cosmological development or time

Another major problem of the Drake Equation is that it does not account for two rather important variables: cosmological developmental phases and time (see Cirkovic, "The Temporal Aspect of the Drake Equation and SETI").

More specifically, it does not take into consideration such factors as the age of the Galaxy, the time at which intelligence first emerged, or the presence of physiochemical variables necessary for the presence of life (such as metallicity required to form planets). The equation assumes a sort of cosmological uniformity rather than a dynamic and ever changing universe.

For example, the equation asks us to guess the number of Earth-like planets, but it does not ask us when there were Earth-like planets. And intelligence itself may have been present as long as 2 to 4.5 billion years ago.

The Galaxy's extreme age and the potential for intelligence to have emerged at disparate points in time leaves an absurdly narrow window for detecting radio signals. The distances and time-scales in question are mind-boggingly vast. SETI, under its current model, is conducting an incredibly futile search.

Detecting ETI's

Which leads to the next problem, that of quantifying the number of radio emitting civilizations. I'm sure that back in the 1960's it made a lot of sense to think of radio capability as a fairly advanced and ubiquitous means of communication, and by consequence, an excellent way to detect the presence and frequency of extraterrestrial civilizations.

But time has proven this assumption wrong. Our radio window is quickly closing and it will only be a matter of time before Earth stops transmitting these types of signals -- at least unintentionally (active SETI is a proactive attempt to contact ETI's with radio signals).

Due to this revelation, the entire equation as a means to both classify and quantify certain types of civilizations becomes quite meaningless and arbitrary. At best, it's a way of searching for a very narrow class of civilizations under very specific and constrained conditions.

Rather, SETI should continue to redefine the ways in which ETI's could be detected. They should try to predict future means of communication (like quantum communication schemes) and ways to identify these signals. They should also look for artificial objects such as megascale engineering and artificial calling cards (see Arnold, "Transit Lightcurve Signatures of Artificial Objects").

The future of advanced intelligence

Although possibly outside the auspices of this discussion, the Drake Equation does not account for the presence of post-radio capable civilizations, particularly post-Singularity machine intelligences. This is a problem because of what these types of civilizations might be capable of.

The equation is used to determine the number of radio capable civilizations as they conduct their business on their home planet. Again, this is a vary narrow view of ETI's and the space of all possible advanced civilizational types. Moreover, it does not account for any migratory tendency that advanced civs may have.

The Drake Equation does not tell us about exponential civilizational growth on account of Von Neumann probe disbursement. It does not tell us where advanced ETI's may be dwelling or what they're up to (e.g. Are they outside the Galaxy? Do they live inside Jupiter Brains? Do they phase shift outside of what we regard as habitable space? etc.). This is a serious shortcoming because the answers to these questions should help us determine not just where we should be looking, but they can also provide us with insight as to the makeup of advanced intelligence life and our own potential trajectory.

In other words, post-Singularity ETI's may represent the most common mode of existence for late-stage civilizations. And that's who we should be looking for rather than radio transmitting civs.

Are we alone?

Michael Crichton once put out a very weak argument against the Drake Equation. He claimed that SETI was a religious endeavor because it was a search for imaginary entities. He is wrong, of course; we should most certainly search for data where we think we might find it. I believe, despite the low odds, that it is reasonable to assume that our search for life on other planets is warranted. Even a negative result can be meaningful.

Consequently, SETI should keep listening, but expect to hear nothing. If we should suddenly hear something from the depths of space, then we will have to seriously re-evaluate our assumptions.

At the same time we should find better ways to detect advanced life and tweak the Drake Equation in such a way as to account for the missing variables and factors I mentioned earlier.

Again, and more generally, we should probably adopt the contact pessimist's frame. Back in the 60's and 70's, when the contact optimists like Sagan, Shklovskii and Drake ruled the Earth, it was not uncommon to think that N in the equation fell somewhere between 10x6 to 10x9.

These days, in the post Tipler and Hart era of astrosociobiology, cosmologists and astrobiologists have to take such factors into consideration as Von Neumann probes, the Fermi Paradox, the Rare Earth Hypothesis, stronger variants of the anthropic principle and catastrophism.

Put another way, as we continue to search for advanced ETI's, and as we come to discover the absurdity of our isolation here on Earth, we may have no choice but to accept the hypothesis that advanced life does not venture out into space for whatever reason (the most likely being self-destruction).

Our other option is to cross our fingers and hope that something radical and completely unpredictable lies on the other side of the technological Singularity.

The Drake Equation is obsolete

Copyright Lynette Cook

I'm surprised how often the Drake Equation is cited when discussing such things as the Search for Extra Terrestrial Intelligence (SETI), astrobiology, and such problems as the Fermi Paradox. Frank Drake's famous equation, which he developed back in 1961, leaves much to be desired in terms of what it's supposed to tell us about both the nature and predominance of extraterrestrial life in our Galaxy.

Fairly recent insights in the fields of cosmology, astrobiology and various future studies have revealed a number of weaknesses in Drake's equation. Ultimately, the equation tells us very little about life on other planets and how we should conduct our searches for signs of the presence of extraterrestrial life.

The Drake Equation

The Drake equation states that:

where:

N is the number of civilizations in our galaxy, with which we might hope to be able to communicate and:

R* is the average rate of star formation in our galaxy
fp is the fraction of those stars that have planets
ne is the average number of planets that can potentially support life per star that has planets
fl is the fraction of the above that actually go on to develop life at some point
fi is the fraction of the above that actually go on to develop intelligent life
fc is the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
L is the length of time such civilizations release detectable signals into space.

Arbitrary at best

The integers that are plugged into this equation are often subject to wide interpretation and can vary greatly from scientist to scientist. Even the slightest change in the equation can result in vastly different answers. Part of the problem is that our understanding of cosmology and astrobiology is changing rapidly and there is often very little consensus among specialists as to what the variables should be.

Consequently, the it is a formula that relies on 'stabs in the dark.' This makes it highly imprecise and unscientific. The margin of error is far beyond what should be considered acceptable or meaningful.

No accounting for cosmological development and time

Another major problem of the Drake Equation is that it does not account for two rather important variables: cosmological developmental phases and time (see Cirkovic, "The Temporal Aspect of the Drake Equation and SETI").

More specifically, it does not take into consideration such factors as the age of the Galaxy, when intelligence first emerged, or the presence of physiochemical variables necessary for the presence of life (such as metallicity required to form planets). Intelligence, for example, may have been present as early as 2 to 4.5 billion years ago. The equation assumes a sort of cosmological uniformity rather a dynamic and ever changing universe that is the case.

For example, the equation asks us to guess the number of Earth-like planets, but it does not ask us when they were Earth-like.

A consequence of the age of the Galaxy and the potential for life to have emerged at disparate points in time leaves an absurdly narrow window for detecting radio signals. The distances and time-scales in question are mind-boggingly vast. SETI, under its current model, is conducting an incredibly futile search.

Detecting ETI's

Which leads to the next problem, that of quantifying the number of radio emitting civilizations. I'm sure that back in the 1960's it made a lot of sense to think of radio capability as a fairly advanced and ubiquitous means of communication, and as a result, an excellent way to detect the presence and number of extraterrestrial intelligences.

But time has proven that assumption wrong. Our radio window is quickly closing and it will only be a matter of time before Earth stops transmitting these types of signals -- at least unintentionally (Active SETI is an attempt to deliberately contact ETI's with radio signals).

Due to this revelation, the entire equation as a means to both classify and quantify certain types of civilizations is rather meaningless and arbitrary. At best, it's a way of searching for a very narrow class of civilizations under very specific and constrained conditions.

Instead, SETI should continue to redefine the ways in which ETI's could be detected. They should try to predict future means of communication (like quantum communication schemes) and ways to identify these signals. They should also look for artificial objects such a megaprojects and artificial calling cards (see Arnold, "Transit Lightcurve Signatures of Artificial Objects."

The future of advanced intelligence

Although this could be considered outside the auspices of the Drake Equation, it does not account for the presence of post-radio capable civilizations, particularly post-Singularity machine intelligences. This is a problem because of what these types of civilizations will be capable of.

The equation is a metric of sorts that is used to determine the number of radio capable civilizations as they conduct their business on their home planet. Again, this is a vary narrow view of ETI's and the space of all possible advanced civilization types. Moreover, it does not account for the migratory tendencies of advanced civs.

The Drake Equation does not tell us about exponential civilizational growth on account of Von Neumann probe disbursement. It does not tell us where advanced ETI's may be dwelling or what they're up to (e.g. Are they outside the Galaxy? Do they live inside Jupiter Brains? Do they phase shift outside of what we regard as habitable space? etc.). This is a serious shortcoming because the answers to these questions should help us determine not just where we should be looking, but it will also provide us with insight as to the makeup of advanced intelligence life and our own trajectory. In other words, post-Singularity ETI's may represent the most common mode of existence of late-stage civilizations rather than radio emitting civilizations.

Are we alone?

Michael Crichton once put out a very weak argument against the Drake Equation. He claimed that SETI was a religious endeavor in search of entities that we had no way of knowing exist. He was wrong of course; we should most certainly search for data we think might exist. I believe there is more than fair grounds to assume that by virtue of our existence that our search for life on other planets is warranted. Even a negative result can be meaningful.

Consequently, SETI should keep listening, but expect to hear nothing. If we should suddently hear something from the depths of space, then we will have to seriously re-evaluate our assumptions. At the same time we should find ways to detect advanced life and tweak the Drake Equation in such a way as to account for the missing variables and factors I mentioned.

Again, as I've harped on before, we should probably adopt the contact pessimist's frame. Back in the 60's and 70's when the contact optimists like Sagan, Shklovskii and Drake ruled the Earth it was not uncommon to think that N in the equation equaled 10x6 to 10x9.

These days, in the post Tiper and Hart era of astrosociobiology, cosmologists and astrobiologists have to take such things into consideration as Von Neumann probes, the Fermi Paradox, the Rare Earth Hypothesis, stronger variants of the anthropic principle and catastrophism.

Put another way, as we continue to search for advanced ETI's, and as we come to discover the absurdity of our isolation here on Earth, we may have no choice but to accept the hypothesis that human civilization will not survive this century.

Our other option is to cross our fingers and hope that something radical and completely unpredictable lies on the other side of the technological Singularity.

Latest podcast available

My latest audiocast has been posted here. You can subscribe to this feed.

In this episode I ask the question: when did intelligence first emerge in the Universe? I also discuss the stupidity of Star Trek's Prime Directive, bald women in science fiction, and mind-controlling parasites.