Language in the Cosmos II: Hello There GJ273b

Ramfjordmoen Facility EISCAT

The ‘Language in the Cosmos’ symposium

Three times in October, 2017 researchers turned a powerful radar telescope near Tromsø, Norway towards an invisibly faint star in the constellation Canis Minor (the small dog) and beamed a coded message into space in an attempt to signal an alien civilization. This new attempt to find other intelligent life in the universe was reported in a presentation at the ‘Language in the Cosmos’ symposium held on May 26 in Los Angeles, California.

METI International sponsored the symposium. This organization was founded to promote messaging to extraterrestrial intelligence (METI) as a new approach to in the search for extraterrestrial intelligence (SETI). It also supports other aspects of SETI research and astrobiology. The symposium was held as part of the International Space Development Conference sponsored by the National Space Society. It brought together linguists and other scientists for a daylong program of 11 presentations. Dr. Sheri Wells-Jensen, who is a linguist from Bowling Green State University in Ohio, was the organizer.

METI International
METI International

This is the second of a two part series about METI International’s symposium. It will focus on a presentation given at the symposium by the president of METI International, Dr. Douglas Vakoch. He spoke about a project that hasn’t previously gotten much attention: the first attempt to send a message to a nearby potentially habitable exoplanet, GJ273b. Vakoch led the team that constructed the tutorial portion of the message.

Douglas Vakoch interstellar message
Dr. Douglas Vakoch, president of METI International. (Credit: Per Bifrost public domain)

Message to the stars

The modern search for extraterrestrial intelligence began in 1960. This is when astronomer Frank Drake used a radio telescope in West Virginia to listen for signals from two nearby stars. Astronomers have sporadically mounted increasingly sophisticated searches, when funding has been available. The largest current project is Breakthrough Listen, funded by billionaire Yuri Milner. Searches have been made for laser as well as radio signals. Researchers have also looked for the megastructures that advanced aliens might create in space near their stars. METI International advocates an entirely new approach in which messages are transmitted to nearby stars in hopes of eliciting a reply.

The project to send a message to GJ273b was a collaboration between artists and scientists. It was initiated by the organizers of the Sónar Music, Creativity, and Technology Festival. The Sónar festival has been held every year since 1994 in Barcelona, Spain. The organizers wanted to commemorate the 25th anniversary of the festival. To implement the project, the festival organizers sought the help of the Catalonia Institute of Space Studies (IEEC), and METI International.

Sónar music festival and interstellar message
The Sónar Music, Creativity, and Technology Festival of Barcelona, Spain was a sponsor of the message to GJ273b.

To transmit the message, the team turned to The European Incoherent Scatter Scientific Association (EISCAT) which operates a network of radio and radar telescopes in Finland, Norway, and Sweden. This network is primarily used to study interactions between the sun and Earth’s ionosphere and magnetic field from a vantage point north of the arctic circle. The message was transmitted from a 32 meter diameter steerable dish at EISCAT’s Ramfjordmoen facility near Tromso, Norway, with a peak power of 2 megawatts. It is the first interstellar message ever to be sent towards a known potentially habitable exoplanet.

The target system

The obscure star known by the catalogue designation GJ273 caught the attention of the Dutch-American astronomer Willem J. Luyten in 1935. Luyten was researching the motions of the star. The star caught his attention because it was moving through Earth’s sky at the surprising rate of 3.7 arc seconds per year. Later study showed that this fast apparent motion is due to the fact that GJ273 is one of the sun’s nearest neighbors, just 12.4 light years away. It is the 24th closest star to the sun. Because of Luyten’s discovery it is sometimes known as Luyten’s star.

Luyten’s star is a faint red dwarf star with only a quarter of the sun’s mass. It caught astronomers’ attention again in March 2017. That’s when an exoplanet, GJ273b, was discovered in it’s habitable zone. The habitable zone is the range of distances where a planet with an atmosphere similar to Earth’s would, theoretically, have a range of temperatures suitable to have liquid water on its surface. The planet is a super Earth, with a mass 2.89 times that of our homeworld. It orbits just 800,000 miles from its faint sun, which it circles every 18 Earth days.

habitable exoplanet interstellar message
Artist’s impression of a habitable exoplanet orbiting a red dwarf star. The habitability of the planets of red dwarf stars is conjectural (Credit ESO/M. Kornmesser public domain)

This exoplanet was chosen because of its proximity to Earth, and because it is visible in the sky from the transmitter’s northerly location. Because GJ273b is relatively nearby, and radio messages travel at the speed of light, a reply from the aliens could come as early as the middle of this century.

The Message

Comparisons with Voyager

The GJ273b transmission is not the first time a message intended for extraterrestrials has been sent into space. Probably the most familiar interstellar message is the one carried on board the Voyager 1 and 2 spacecraft. NASA launched these interplanetary robots in 1977. They traveled on trajectories that hurtled them into interstellar space after they completed their missions to explore the outer solar system.

The message carried aboard each Voyager spacecraft was encoded digitally on a phonographic record. It was largely pictorial, and attempted to give a comprehensive overview of humans and Earth. It also included a selection of music from various Earthly cultures. These spacecraft will take tens of thousands of years to reach the stars. So, no reply can be expected on a timescale relevant to our society.

In some ways the GJ273b message is very different from the Voyager message. Unlike the Voyager record, it isn’t pictorial and doesn’t attempt to give a comprehensive overview of humans and Earth. This is perhaps because, unlike the Voyager message, it is intended to initiate a dialog on a timescale of decades. It resembles the Voyager message in that it contains music from Earth, namely, music from the artists that performed at the Sónar music festival.

Saying hello

For the human reader, understanding the message is a bit more of a challenge than looking at the pictures encoded on the Voyager record. You can try your hand at decoding the message yourself, because the organizers posted the whole thing on their website. Be forewarned that if you continue reading here, there are spoilers (or helpful clues, depending on how you look at it).

The message consists of a string of binary digits—ones and zeros. These are represented in the signal by a shift between two slightly different radio frequencies. The ‘hello’ section is designed to catch the attention of alien listeners. It consists of a string of prime numbers (numbers divisible only by themselves and one). They are represented with binary digits like this:

01001100011100000111110000000000011111111111

The message continues the sequence up to 193. A signal like this almost certainly can’t be produced by natural processes, and can only be the designed handiwork of beings who know math.

The tutorial

After the ‘hello’ section comes the tutorial. This, and all the rest of the message, uses eight bit blocks of binary digits as the basis for its symbols. The tutorial begins by introducing number symbols by counting. It uses base two numbers like this:

10000000 (0) 10000001 (1) 10000010 (2) 10000011 (3)
10000100 (4) 10000101 (5) 10000110 (6) 10000111 (7)
10001000 (8) 10001001 (9) 10001010 (10)

The leading ‘1’ allows numbers to be distinguished from other 8 bit symbols that don’t represent numbers.

After counting, the tutorial introduces symbols for the operations of arithmetic by showing sample problems. Here’s a sampling of some of the symbols for math operations:

00000110 (+) 00000111 (-) 00001000 (×) 00001001 (÷)
00111100 (=)

The tutorial then proceeds to geometry using combinations of numbers and symbols to illustrate the Pythagorean theorem. It eventually progresses to sine waves, thereby describing the radio wave carrying the signal itself. Finally the tutorial describes the physics of sound waves and the relationships between musical notes.

Besides the numbers, the tutorial introduces 55 8-bit symbols in all. It provides the instructions that aliens would need to properly reproduce a series of digitally encoded musical selections from the Sónar Festival.

During its journey of 70 trillion miles, the message is sure to become corrupted with noise. To compensate, the tutorial was transmitted three times during each transmission, requiring a total of 33 minutes to transmit. The entire transmission was repeated on three separate days, October 16, 17, and 18, 2017. A second block of three transmissions was made on May 14, 15, and 16, 2018.

The music

Each transmission included a different selection of music, with the works of 38 different musicians included in all. You can hear recordings of all this music at the Sónar Calling GJ273b website.

The rationale behind the message

Current and past SETI projects conducted by astronomers here on Earth assume that advanced aliens would make things easy for newly emerging civilizations by establishing powerful beacons that would broadcast in all directions at all times. Thus, SETI searchers generally use the same sort of highly directional dish antennae often used for other research in radio astronomy. They listen to any one star for only a few minutes, searching each one in turn for the beacon.

Unlike the always-on beacons imagined as the objects of Earth’ SETI searches, the Sónar message was only transmitted for 33 minutes on each of three days, and on only two occasions. Vakoch admits that “our message would likely be undetected by a civilization on GJ273b using the same strategy” favored by beacon searching SETI researchers on Earth.

However, some researchers have called traditional SETI assumptions and strategy into question, and studies of alternative search technologies have already been conducted. Vakoch notes that “we humans already have the technological capacity, and need only the funding, to conduct an all-sky survey that would detect intermittent transmission like ours”.

A larger problem is that the message was directed at just one planet. Although GJ273b orbits within its star’s habitable zone, we really know little what that means for whether the planet is actually habitable, or whether it has life or intelligence. Earth itself has been habitable for billions of years. But it has only had a civilization capable of radio transmissions for a century.

Vakoch conceded that “The only way we will get a reply back from GJ273b is if the galaxy is chock full of intelligent life, and it is out there just waiting for us to take the initiative. More realistically, we may need to replicate this process with hundreds, thousands, or even millions of stars before we reach one with an advanced civilization that can detect our signal”. METI International aims to conduct a design study for such a large scale METI project in hopes that funding will materialize from governmental or other sources.

References and further reading:

Sónar Calling GJ273b

Cain F. (2013) How could we find aliens, Universe today.

Patton, P. E. (2018) Language in the Cosmos I: Is universal grammar really universal?, Universe Today.

Patton P. E. (2016) Alien Minds, I. Are extraterrestrial civilizations likely to evolve, II. Do aliens think big brains are sexy too?, III. The octopus’s garden and the country of the blind, Universe Today

Patton, P. E. (2015) Who speaks for Earth? The controversy over interstellar messaging, Universe Today.

Patton P. E. (2014) Communicating across the cosmos. Part 1: Shouting into the darkness, Part 2: Petabytes from the stars, Part 3: Bridging the vast gulf, Part 4: Quest for a Rosetta Stone, Universe Today.

Vakoch D. A. (2017) New keys to help extraterrestrials unlock our messages, Scientific American, Observations.

Vakoch D. A. (2011) Responsibility, capability and Active SETI: Policy, law, ethics, and communication with extraterrestrial intelligence, Acta Astronautica, 68:512-519

Vakoch D. A. (2010) An iconic approach to communicating musical concepts in interstellar messages, Acta Astronautica, 67:1406-1409

Language in the Cosmos I: Is Universal Grammar Really Universal?

Chomsky (right), octopus (left), universal grammar

The METI Symposium

The symposium

How could you devise a message for intelligent creatures from another planet? They wouldn’t know any human language. Their ‘speech’ might be as different from ours as the eerie cries of whales or the twinkling lights of fireflies. Their cultural and scientific history would have followed its own path. Their minds might not even work like ours. Would the deep structure of language, its so called ‘universal grammar’ be the same for aliens as for us? A group of linguists and other scientists gathered on May 26 to discuss the challenging problems posed by devising a message that extraterrestrial beings could understand. There are growing hopes that such beings might be out there among the billions of habitable planets that we now think exist in our galaxy. The symposium, called ‘Language in the Cosmos’ was organized by METI International. It took place as part of the National Space Society’s International Space Development Conference in Los Angeles. The Chair of the workshop was Dr. Sheri Wells-Jensen, a linguist from Bowling Green State University in Ohio.

What is METI International?

‘METI’ stands for messaging to extraterrestrial intelligence. METI International is an organization of scientists and scholars that aims to foster an entirely new approach in our search for alien civilizations. Since 1960, researchers have been looking for extraterrestrials by searching for possible messages they might send to us by radio or laser beams. They have sought the giant megastructures that advanced alien societies might build in space. METI International wants to move beyond this purely passive search strategy. They want to construct and transmit messages to the planets of relatively nearby stars, hoping for a response.

One of the organization’s central goals is to build an interdisciplinary community of scholars concerned with designing interstellar messages that can be understood by non-human minds. More generally, it works internationally to promote research in the search for extraterrestrial intelligence and astrobiology, and to understand the evolution of intelligence here on Earth. The daylong symposium featured eleven presentations. It main theme was the role of linguistics in communication with extraterrestrial intelligence.

METI International
METI International

This article

This article is the first in a two part series. It will focus on one of the most fundamental issues addressed at the conference. This is the question of whether the deep underlying structure of language would likely be the same for extraterrestrials as for us. Linguists understand the deep structure of language using the theory of ‘universal grammar’. The eminent Linguist Noam Chomsky developed this theory in the middle of the twentieth century.

Two interrelated presentations at the symposium addressed the issue of universal grammar. The first was by Dr. Jeffery Punske of Southern Illinois University and Dr. Bridget Samuels of the University of Southern California. The second was given by Dr. Jeffrey Watumull of Oceanit, whose coauthors were Dr. Ian Roberts of the University of Cambridge, and Dr. Noam Chomsky himself, of the Massachusetts Institute of Technology.

Chomsky’s universal grammar-For humans only?

Universal grammar

Despite its name, Chomsky originally took his ‘universal grammar’ theory to imply that there are major, and maybe insuperable barriers to mutual understanding between humans and extraterrestrials. Let’s first consider why Chomsky’s theories seemed to make interstellar communication virtually hopeless. Then we’ll examine why Chomsky’s colleagues who presented at the symposium, and Chomsky himself, now think differently.

Before the second half of the twentieth century, linguists believed that the human mind was a blank slate, and that we learned language entirely by experience. These beliefs dated to the seventeenth century philosopher John Locke and were elaborated in the laboratories of behaviorist psychologists in the early twentieth century. Beginning in the 1950’s, Noam Chomsky challenged this view. He argued that learning a language couldn’t simply be a matter of learning to associate stimuli with responses. He saw that young children, even before the age of 5, can consistently produce and interpret original sentences that they had never heard before. He spoke of a “poverty of the stimulus”. Children couldn’t possibly be exposed to enough examples to learn the rules of language from scratch.

Chomsky posited instead that the human brain contained a “language organ”. This language organ was already pre-organized at birth for the basic rules of language, which he called “universal grammar”. It made human infants primed and ready to learn whatever language they were exposed to using only a limited number of examples. He proposed that the language organ arose in human evolution, maybe as recently of 50,000 years ago. Chomsky’s powerful arguments were accepted by other linguists. He came to be regarded as one of the great linguists and cognitive scientists of the twentieth century.

Universal grammar and ‘Martians’

Human beings speak more than 6000 different languages. Chomsky defined his “universal grammar” as “the system of principles, conditions, and rules that are elements or properties of all human languages”. He said it could be taken to express “the essence of human language”. But he wasn’t convinced that this ‘essence of human language’ was the essence of all theoretically possible languages. When Chomsky was asked by an interviewer from Omni Magazine in 1983 whether he thought that it would be possible for humans to learn an alien language, he replied:

“Not if their language violated the principles of our universal grammar, which, given the myriad ways that languages can be organized, strikes me as highly likely…The same structures that make it possible to learn a human language make it impossible for us to learn a language that violates the principles of universal grammar. If a Martian landed from outer space and spoke a language that violated universal grammar, we simply would not be able to learn that language the way that we learn a human language like English or Swahili. We should have to approach the alien’s language slowly and laboriously — the way that scientists study physics, where it takes generation after generation of labor to gain new understanding and to make significant progress. We’re designed by nature for English, Chinese, and every other possible human language. But we’re not designed to learn perfectly usable languages that violate universal grammar. These languages would simply not be within the range of our abilities.”

If intelligent, language-using life exists on another planet, Chomsky knew, it would necessarily have arisen by a different series of evolutionary changes than the uniquely improbable path that produced human beings. A different history of climate changes, geological events, asteroid and comet impacts, random genetic mutations, and other events would have produced a different set of life forms. These would have interacted with one another in a different ways over the history of life on the planet. The “Martian” language organ, with its different and unique history, could, Chomsky surmised, be entirely different from its human counterpart, making communication monumentally difficult, if not impossible.

Convergent evolution and alien minds

The tree of life

Why did Chomsky think that the human and ‘Martian‘ language organ would likely be fundamentally different? How come he and his colleagues now hold different views? To find out, we first need to explore some basic principles of evolutionary theory.

Originally formulated by the naturalist Charles Darwin in the nineteenth century, the theory of evolution is the central principle of modern biology. It is our best tool for predicting what life might be like on other planets. The theory maintains that living species evolved from previous species. It asserts that all life on Earth is descended from an initial Earthly life form that lived more than 3.8 billion years ago.

You can think of these relationships as like a tree with many branches. The base of the trunk of the tree represents the first life on Earth 3.8 billion years ago. The tip of each branch represents now, and a modern species. The diverging branches connecting each branch tip with the trunk represent the evolutionary history of each species. Each branch point in the tree is where two species diverged from a common ancestor.

Evolution, brains, and contingency

To understand Chomsky’s thinking, we’ll start with a familiar group of animals; the vertebrates, or animals with backbones. This group includes fishes, amphibians, reptiles, birds, and mammals, including humans.

We’ll compare the vertebrates with a less familiar, and distantly related group; the cephalopod molluscs. This group includes octopuses, squids, and cuttlefish. These two groups have been evolving along separate evolutionary paths-different branches of our tree-for more than 600 million years. I’ve chosen them because, as they’ve traveled along their separate branch of our evolutionary tree, each has evolved it own sort of complex brains and complex sense organs.

The brains of all vertebrates have the same basic plan. This is because they all evolved from a common ancestor that already had a brain with that basic plan. The octopus’s brain, by contrast, has an utterly different organization. This is because the common ancestor of cephalopods and vertebrates lies much further back in evolutionary time, on a lower branch of our tree. It probably had only the simplest of brains, if any at all.

With no common plan to inherit, the two kinds of brains evolved independently of one another. They are different because evolutionary change is contingent. That is, it involves varying combinations of influences, including chance. Those contingent influences were different along the path that produced cephalopod brains, than along the one that led to vertebrate brains.

Chomsky believed that many languages might be theoretically possible that violated the seemingly arbitrary constraints of human universal grammar. There didn’t seem to be anything that made our actual universal grammar something special. So, because of the contingent nature of evolution, Chomsky assumed that the ‘Martian’ language organ would arrive at one of these other possibilities, making it fundamentally different from its human counterpart.

This sort of evolution-based pessimism about the likelihood that humans and aliens could communicate is widespread. At the symposium, Dr. Gonzalo Munévar of Lawrence Technological University argued that intelligent creatures that evolved sensory systems and cognitive structures different from ours would not develop similar scientific theories or even similar mathematics.

Evolution, eyes, and convergence

Now lets consider another feature of the octopus and other cephalopods; their eyes. Surprisingly, the eyes of octopuses resemble those of vertebrates in intricate detail. This uncanny resemblance can’t be explained in the same way as the general resemblance of vertebrate brains to one another. It’s almost certainly not due to inheritance of the traits from a common ancestor. It’s true that some of the genes involved in the building of eyes are the same in most animals, appearing far down towards the trunk of our evolutionary tree. But, biologists are almost certain that the common ancestor of cephalopods and vertebrates was much too simple to have any eyes at all.

Biologists think eyes evolved separately more than forty times on Earth, each on its own branch of the evolutionary tree. There are many different kinds of eyes. Some are so strangely different from our own that even a science fiction writer would be surprised by them. So, if evolutionary change is contingent, why do octopus eyes bear a striking and detailed similarity to our own? The answer lies outside of evolutionary theory, with the laws of optics. Many large animals, like the octopus, need acute vision. There is only one good way, under the laws of optics, to make an eye that meets the needed requirements. Whenever such an eye is needed, evolution finds this same best solution. This phenomenon is called convergent evolution.

Life on another planet would have its own separate evolutionary tree, with the base of the trunk representing the appearance of life on that planet. Because of the contingency of evolutionary change, the pattern of branches might be quite different from our Earthly evolutionary tree. But because the laws of optics are the same everywhere in the universe, we can expect that large animals under similar conditions will evolve an eye that looks a lot like that of a vertebrate or a cephalopod. Convergent evolution is potentially a universal phenomenon.

eye evolution universal grammar
The eye of a fish (left), which is an aquatic vertebrate, and that of a cephalopod mollusc like the octopus (right) are almost identical, but the two evolved independently. Their remarkable similarity is due to convergent evolution. The common ancestor of fishes and cephalopods did not have a well developed eye, nor do some molluscs that are not cephalopods. This sort of eye is called a camera eye, because its layout is similar to a camera with the lens at the front, and the light sensing retina at the back (Credit: Jerry Crimson Mann public domain, evolution diagram is by the author).

Not just for humans anymore?

Taking apart the language organ

Jeff Punske universal grammar
Jeffrey Punske, Assistant Professor of Linguistics, Southern Illinois University

By the beginning of the twenty-first century, Chomsky and some of his colleagues started to look at the language organ and universal grammar in a new way. This new view made it seem like the properties of universal grammar were inevitable, much as the laws of optics made many features of the octopus’s eye inevitable.

In a 2002 review, Chomsky and his colleagues Marc Hauser and Tecumseh Fitch argued that the language organ can be decomposed into a number of distinct parts. The sensory-motor, or externalization, system is involved in the mechanics of expressing language through methods like vocal speech, writing, typing, or sign language. The conceptual-intentional system relates language to concepts.

Bridget Samuels universal grammar
Bridget Samuels, Center for Craniofacial Anatomy, University of Southern California

The core of the system, the trio proposed, consists of what they called the narrow faculty of language. It is a system for applying the rules of language recursively, over and over, thereby allowing the construction of an almost endless range of meaningful utterances. Jeffrey Punske and Bridget Samuels similarly spoke of a ‘syntactic spine’ of all human languages. Syntax is the set of rules that govern the grammatical structure of sentences.

The inevitability of universal grammar

Chomsky and his colleagues made a careful analysis of what computations a nervous system might need to perform in order to make this recursion possible. As an abstract description of how the narrow faculty works, the researchers turned to a mathematical model called the Turing machine. The mathematician Alan Turing developed this model early in the twentieth century. This theoretical ‘machine’ led to the development of electronic computers.

Their analysis led to a striking and unexpected conclusion. In a book chapter currently in press, Watumull and Chomsky write that “Recent work demonstrating the simplicity and optimality of language increases the cogency of a conjecture that at one time would have been summarily dismissed as absurd: the basic principles of language are drawn from the domain of (virtual) conceptual necessity”. Jeffrey Watumull wrote that this strong minimalist thesis posits that “there exist constraints in the structure of the universe itself such that systems cannot but conform”. Our universal grammar is something special, and not just one among many theoretical possibilities.

Ian Roberts universal grammar
Ian Roberts, Professor of Linguistics, Faculty of Medieval and Modern Languages, Cambridge University

Plato and the strong minimalist thesis

The constraints of mathematical and computational necessity shape the narrow faculty to be as it is, just like the laws of optics shape both the vertebrate and the octopus eye. ‘Martian’ languages, then, might follow the same universal grammar as human languages because there is only one best way to make the recursive core of the language organ.

Through the process of convergent evolution, nature would be compelled to find this one best way wherever and whenever in the universe that language evolves. Watumull supposed that the brain mechanisms of arithmetic might reflect a similarly inevitable convergence. That would mean that the basics of arithmetic would also be the same for humans and aliens. We must, Watumull and Chomsky wrote “rethink any presumptions that extraterrestrial intelligence or artificial intelligence would really be all that different from human intelligence”.

This is the striking conclusion that Watumull, and in a complementary way, Punske and Samuels presented at the symposium. Universal grammar may actually be universal, after all. Watumull compared this thesis to a modern, computer age version of the beliefs of the ancient Greek philosopher Plato, who maintained that mathematical and logical relationships are real things that exist in the world apart from us, and are merely discovered by the human mind. As a novel contribution to a difficult ages-old philosophical problem, these new ideas are sure to stir controversy. They illustrate the depth of new knowledge that awaits us as we reach out to other worlds and other minds.

universal grammar
The ancient Greek philosopher Plato as imagined by the Renaissance painter Raphael. Plato maintained that mathematical and logical truths existed objectively, apart from our mind and were merely discovered by humans. Jeffrey Watumull, Ian Roberts, and Noam Chomsky’s view of the narrow faculty of language are a modern day version of Plato’s views, in which necessary mathematical, logical, and computational relationships determine the structure of the language faculty, and universal grammar. Since the same necessary relationships would influence the evolution of the language faculty of aliens, alien languages, they contend, are likely to have the same universal grammar as human languages.

Universal grammar and messages for aliens

What are the consequences of this new way of thinking about the structure of language for practical attempts to create interstellar messages? Watumull thinks the new thinking is a challenge to “the pessimistic relativism of those who think it overwhelmingly likely that terrestrial (i.e. human) intelligence and extraterrestrial intelligence would be (perhaps in principle) mutually unintelligible”. Punske and Samuels agree, and think that “math and physics likely represent the best bet for common concepts that could be used as a starting point”.

Watumull supposes that while the minds of aliens or artificial intelligences may be qualitatively similar to ours, they may differ quantitatively in having bigger memories, or the ability to think much faster than us. He is confident that an alien language would likely include nouns, verbs, and clauses. That means they could probably understand an artificial message containing such things. Such a message, he thinks, might also profitably include the structure and syntax of natural human languages, because this would likely be shared by alien languages.

Punske and Samuels seem more cautious. They note that “There are some linguists who don’t believe nouns and verbs are universal human language categories”. Still, they suspect that “alien languages would be built of discrete meaningful units that can combine into larger meaningful units”. Human speech consists of a linear sequence of words, but, Punske and Samuels note that “Some of the linearity imposed on human language may be due to the constraints of our vocal anatomy, and already starts to break down when we think about signed languages”.

Overall, the findings foster new hope that devising a message comprehensible to extraterrestrials is feasible. In the next installment, we will look at a new example of such a message. It was transmitted in 2017 towards a star 12 light years from our sun.

References and further reading

Allman J. (2000) Evolving Brains, Scientific American Library

Chomsky, N. (2017) The language capacity: Architecture and evolution, Psychonomics Bulletin Review, 24:200-203.

Gliedman J. (1983) Things no amount of learning can teach, Omni Magazine, chomsky.info

Hauser, M. D. , Chomsky, N. , and Fitch W. T. (2002) The faculty of language: What is it, Who has it, and How did it evolve? Science, 298: 1569-1579.

Land, M. F. and Nilsson, D-E. (2002) Animal Eyes, Oxford Animal Biology Series

Noam Chomsky’s theories on language, Study.com

Patton P. E. (2014) Communicating across the cosmos. Part 1: Shouting into the darkness, Part 2: Petabytes from the stars, Part 3: Bridging the vast gulf, Part 4: Quest for a Rosetta Stone, Universe Today.

Patton P. E. (2016) Alien Minds, I. Are extraterrestrial civilizations likely to evolve, II. Do aliens think big brains are sexy too?, III. The octopus’s garden and the country of the blind, Universe Today

Alien Minds Part III: The Octopus’s Garden and the Country of the Blind

METI logo

In our galaxy, there may be, at least, tens of billions of habitable planets, with conditions suitable for liquid water on their surfaces. There may be habitable moons as well. On an unknown number of those worlds, life may have arisen. On an unknown fraction of life-bearing worlds, life may have evolved into complex multicellular, sexually reproducing forms.

During its habitable period, a world with complex life might produce hundreds of millions of evolutionary lineages. One or a few of them might fortuitously encounter special circumstances that triggered runaway growth of their intelligence. These favored few, if they exist, might have built technological civilizations capable of signaling their presence across interstellar distances, or detecting and deciphering a message we send their way. What might such alien minds be like? What senses might they use? How might we communicate with them?

METI International
METI International

The purposes of the newly created METI (Messaging to ExtraTerrestrial Intelligence) International include fostering multidisciplinary research in the design and transmission of interstellar messages, and building a global community of scholars from the natural sciences, social sciences, humanities, and arts concerned with the origin, distribution, and future of life in the universe.

On May 18 the organization sponsored a workshop which included presentations by biologists, psychologists, cognitive scientists, and linguists. This is the third and final installment of a series of articles about the workshop.

In previous installments, we’ve discussed some ideas about the evolution of intelligence that were featured at the workshop. Here we’ll see whether our Earthly experience can provide us with any clues about how we might communicate with aliens.

Many of the animals that we are most familiar with from daily life, like humans, cats, dogs, birds, fishes, and frogs are vertebrates, or animals with backbones. They are all descended from a common ancestor and share a nervous system organized according to the same basic plan.

Molluscs are another major group of animals that have been evolving separately from vertebrates for more than 600 million years. Although most molluscs, like slugs, snails, and shellfish, have fairly simple nervous systems, one group; the cephalopods, have evolved a much more sophisticated one.

the common octopus
The common octopus, Octopus vulgaris, Is a cephalopod mollusc, has evolved sophisticated cognition and perception along a very different evolutionary path than have human beings and our relatives. The brain is located between the eyes. The large bulbous structure below the eyes is the mantle, a muscular organ involved in swimming. Public domain.

Cephalopods include octopuses, squids, and cuttlefishes. They show cognitive and perceptual abilities rivaling those of our close vertebrate kin. Since this nervous system has a different evolutionary history than of the vertebrates, it is organized in a way completely different from our own. It can give us a glimpse of the similarities and differences we might expect between aliens and ourselves.

David Gire, an associate professor of psychology at the University of Washington, and researcher Dominic Sivitilli gave a presentation on cephalopods at the Puerto Rico workshop. Although these animals have a sophisticated brain, their nervous systems are much more decentralized than that of familiar animals. In the octopus, sensing and moving are controlled locally in the arms, which together contain as many nerve cells, or neurons, as the brain.

David Gire
Dr. David Gire is an Assistant Professor in the Department of Psychology at the University of Washington and a behavioral neuroscientist. He presented at the Puerto Rico workshop on cephalopod intelligence.

The animal’s eight arms are extraordinarily sensitive. Each containing hundreds of suckers, with thousands of sensory receptors on each one. By comparison, the human finger has only 241 sensory receptors per square centimeter. Many of these receptors sense chemicals, corresponding roughly to our senses of taste and smell. Much of this sensory information is processed locally in the arms. When an arm is severed from an octopus’s body, it continues to show simple behaviors on its own, and can even avoid threats. The octopus’s brain simply acts to coordinate the behaviors of its arms.

Cephalopods have acute vision. Although their eyes evolved separately from those of vertebrates, they nonetheless bear an eerie resemblance. They have a unique ability to change the pattern and color of their skin using pigment cells that are under direct control of their nervous systems. This provides them with the most sophisticated camouflage system of any animal on Earth, and is also used for social signaling.

Despite the sophisticated cognitive abilities it exhibits in the lab, the octopus is largely solitary.
Cephalopod groups exchange useful information by observing one another, but otherwise exhibit only limited social cooperation. Many current theories of the evolution of sophisticated intelligence, like Miller’s sapiosexual hypothesis, which was featured in the second installment, assume that social cooperation and competition play a central role in the evolution of complicated brains. Since cephalopods have evolved much more impressive cognitive abilities than other molluscs, their limited social behavior is surprising.

Dominic Sivitilli
Dominic Sivitilli is a post-baccalaureate researcher in the laboratory of David Gire, studying responses to chemical signals by the octopus. He is the co-presenter of a talk on cephalopod cogntition at the METI International Puerto Rico conference. METI International used with permission.

Maybe the limited social behavior of cephalopods really does set limits on their intelligence. However, Gire and Sivitilli speculate that perhaps “an intelligence capable of technological development could exist with minimum social acuity”, and the cephalopod ability to socially share information is enough. The individuals of such an alien collective, they suppose, might possess no sense of self or other.

Besides Gire and Sivitilli, Anna Dornhaus, whose ideas were featured in the first installment, also thinks that alien creatures might function together as a collective mind. Social insects, in some respects, actually do. She doubts, though, that such an entities could evolve human-like technological intelligence without something like Miller’s sapiosexuality to trigger a runaway explosion of intelligence.

But if non-sapiosexual alien technological civilizations do exist, we might find them impossible to comprehend. Given this possible gulf of incomprehension about social structure, Gire and Stivitilli suppose that the most we might aspire to accomplish in terms of interstellar communication is an exchange of mutually useful and comprehensible astronomical information.

Workshop presenter Alfred Kracher, a retired staff scientist at the Ames Laboratory of the University of Iowa, supposes that “the mental giants of the Milky Way are probably artificially intelligent machines… It would be interesting to find evidence of them, if they exist”, he writes, “but then what?” Kracher supposes that if they have emancipated themselves and evolved away from their makers, “they will have nothing in common with organic life forms, human or extraterrestrial. There is no chance of mutual understanding”. We will be able to understand aliens, he maintains, only if “it turns out that the evolution of extraterrestrial life forms is highly convergent with our own”.

Peter Todd, a professor of psychology from Indiana University, holds out hope that such convergence may actually occur. Earthly animals must solve a variety of basic problems that are presented by the physical and biological world that they inhabit.

They must effectively navigate through a world of surfaces, barriers and objects, finding food and shelter, and avoiding predators, parasites, toxins. Extraterrestrial organisms, if they evolve in an Earth-like environment, would face a generally similar set of problems. They may well arrive at similar solutions, just as the octopus evolved eyes similar to ours.

In evolution here on Earth, Todd notes, brain systems originally evolved to solve these basic physical and biological problems appear to have been re-purposed to solve new and more difficult problems, as some animals evolved to solve the problems of living and finding mates as members of societies, and then as one particular ape species went on to evolve conceptual reasoning and language. For example, disgust at bad food, useful for avoiding disease, may have been become the foundation for sexual disgust to avoid bad mates, moral disgust to avoid bad clan mates, and intellectual disgust to avoid dubious ideas.

If alien brains evolved solutions similar to the ones our brains did for negotiating the physical and biological world, they they might also have been re-purposed in similar ways. Alien minds might not be wholly different from ours, and thus hope exists for a degree of mutual understanding.

In the early 1970’s the Pioneer 10 and 11 spacecraft were launched on the first exploratory missions to the planet Jupiter and beyond. When their missions were completed, these two probes became the first objects made by humans to escape the sun’s gravitational pull and hurtle into interstellar space.

Because of the remote possibility that the spacecraft might someday be found by extraterrestrials, a team of scientists and scholars lead by Carl Sagan emplaced a message on the vehicle, etched on a metal plaque. The message consisted, in part, of a line drawing of a man and a woman. Later, the Voyager 1 and 2 spacecraft carried a message that consisted, in part, of a series of 116 digital images encoded on a phonographic record.

Use of images in interstellar messages
The use of images in interstellar communication. In 1977, NASA launched the Voyager 1 and 2 spacecraft on a mission to explore the outer solar system. Destined to wander interstellar space forever following the completion of their mission, each spacecraft carried an interstellar message encoded on a phonographic record. The message, designed by SETI pioneers Carl Sagan and Frank Drake and their collaborators, included 116 digital images. This image is intended to show extraterrestrials how human beings eat and drink. Will extraterrestrials understand such images? The limited quality of the image reflects the state of digital imaging technology in the 70’s National Astronomy and Ionosphere Center, public domain.

The assumption that aliens would see and understand images seems reasonable, since the octopus evolved an eye so similar to our own. And that’s not all. The evolutionary biologists Luitfried Von Salvini-Plawen and Ernst Mayr showed that eyes, of various sorts, have evolved forty separate times on Earth, and vision is typically a dominant sense for large, land dwelling animals. Still, there are animals that function without it, and our earliest mammalian ancestors were nocturnal. Could it be that there are aliens that lack vision, and could not understand a message based on images?

In his short story, The Country of the Blind, the great science fiction writer H. G. Wells imagined an isolated mountain village whose inhabitants had been blind for fifteen generations after a disease destroyed their vision.

A lost mountain climber, finding the village, imagines that with his power of vision, he can easily become their king. But the villagers have adapted thoroughly to a life based on touch, hearing, and smell. Instead of being impressed by their visitor’s claim that he can ‘see’, they find it incomprehensible. They begin to believe he is insane. And when they seek to ‘cure’ him by removing two strange globular growths from the front of his head, he flees.

Mexican blind cavefish
The Mexican blind cavefish (Astyanax mexicanus) has lived in the total darkness of a cave system in central Mexico for more than a million years, and has evolved the loss of its eyes. Astyanax possess a sense that land dwelling animals lack. The lateral line sense, which is present in all fishes, allows these animals to sense their near surroundings based on pressure differences in fields of water flow around their bodies. They also have an acute sense of taste, with taste receptors on their bodies as well as in their mouths. The evolution of cave dwelling intelligent life is probably unlikely, since large brains are metabolically expensive, and food is scarce in caves. On the surface, plants capture energy from sunlight and form the base of the food chain. State Museum of Natural History, Karlsruhe.

Could their really be an alien country of the blind whose inhabitants function without vision? Workshop presenter Dr. Sheri Wells-Jensen, an associate professor of Linguistics at Bowling Green State University, doesn’t need to imagine the country of the blind, because, in a sense, she lives there. She is blind, and believes that creatures without vision could achieve a level of technology sufficient to send interstellar messages. “Sighted people”, she writes, “tend to overestimate the amount and quality of information gathered by vision alone”.
Sheri Wells Jensen
Dr. Sheri Wells-Jensen is an associate professor of linguistics at Bowling Green State University. She presented at talk at the Puerto Rico workshop on alternative perceptual systems and interstellar communications. METI International, used with permission.

Bats and dolphins image their dimly lit environments with a kind of naturally occurring sonar called echolocation. Blind human beings can also learn to echolocate, using tongue clicks or claps as emitted signals and analyzing the returning echoes by hearing. Some can do so well enough to ride a bicycle at a moderate pace through an unfamiliar neighborhood. A human can develop the touch sensitivity needed to read braille in four months. A blind marine biologist can proficiently distinguish the species of mollusc shells by touch.

Wells-Jensen posits a hypothetical civilization which she calls the Krikkits, who lack vision but possess sensory abilities otherwise similar to those of human beings. Could such beings build a technological society? Drawing on her knowledge of the blind community and a series of experiments, she thinks they could.

Finding food would present few special difficulties, since blind naturalists can identify many plant species by touch. Agriculture could be conducted as modern blind gardeners do it, by marking crops using stakes and piles of rock, and harvesting by feel. The combination of a stick used as a cane to probe the path ahead and echolocation make traveling by foot effective and safe. A loadstone compass would further aid navigational abilities. The Krikkits might use snares rather than spears or arrows to trap animals, making tools by touch.

Mathematics is vital to building a technological society. For most human beings, with our limited memory, a paper and pencil or a blackboard are essential for doing math. Krikkits would need to find other such aids, such as tactual symbols on clay tablets, abacus-like devices, or patterns sewn on hides or fabric.

Successful blind mathematicians often have prodigious memories, and can perform complex calculations in their heads. One of history’s greatest mathematicians, Leonard Euler, was blind for the last 17 years of his life, but remained mathematically productive through the use of his memory.

The obstacles to a blind society developing technology may not be insurmountable. Blind people are capable of handling fire and even working with molten glass. Krikkits might therefore use fire for cooking, warmth, to bake clay vessels, and smelt metal ores. Initially there only astronomical knowledge would be of the sun as a source of heat. Experiments with loadstones and metals would lead to a knowledge of electricity.

Eventually, the Krikkits might imitate their sonar with radio waves, inventing radar. If their planet possessed a moon or moons, radar reflections from them might provide their first knowledge of astronomical objects other than their sun. Radar would also enable them to learn for the first time that their planet is round.

The Krikkits might learn to detect other forms of radiation like X-rays and ‘light’. The ability to detect this second mysterious form of radiation might allow them to discover the existence of the stars and develop an interest in interstellar communication.

What sorts of messages might they send or understand? Well-Jensen believes that line drawings, like the drawing of the man and the woman on the Pioneer plaque, and other such pictorial representations might be an impenetrable mystery to them. On the other hand, she speculates that Krikkits might represent large data sets through sound, and that their counterpart to charts and graphs might be equally incomprehensible to us.

Images might pose a challenge for the Krikkits, but perhaps, Wells-Jensen concedes, not an impossible one. There is evidence that bats image their world using echolocation. Kikkits might be likely to evolve similar abilities, though Wells-Jensen believes they would not be essential for making tools or handling objects.

Perhaps humans and Krikkits could find common ground by transmitting instructions for three dimensional printed objects that could be explored tactually. Wells-Jensen thinks they might also understand mathematical or logical languages proposed for interstellar communication.

The diversity of cognition and perception that we find here on Earth teaches us that if extraterrestrial intelligence exists, it is likely to be much more alien than much of science fiction has prepared us to expect. In our attempt to communicate with aliens, the gulf of mutual incomprehension may yawn as wide as the gulf of interstellar space. Yet this is a gulf we must somehow cross, if we wish ever to become citizens of the galaxy.

For further reading:

Cain, F. (2008) Is Our Universe Ruled by Artificial Intelligence, Universe Today.

Kaufmann G. (2005) Spineless smarts, NOVA

Land, M. F., and Nilsson, D-E. (2002) Animal Eyes, Oxford University Press.

Mather, J. A. (2008) Cephalopod consciousness: Behavioral evidence, Cognition and Consciousness 17(1): 37-48.

Patton, P. E. (2016) Alien Minds I: Are Extraterrestrial Civilizations Likely to Evolve? Universe Today.

Patton, P. E. (2016) Alien Minds II: Do Aliens Think Big Brains are Sexy Too? Universe Today.

P. Patton (2014) Communicating across the cosmos, Part 1: Shouting into the darkness, Part 2: Petabytes from the Stars, Part 3: Bridging the Vast Gulf, Part 4: Quest for a Rosetta Stone, Universe Today.

Wells, H. G. (1904) The Country of the Blind, The literature network.

Alien Minds Part II: Do Aliens Think Big Brains are Sexy Too?

peahen and peacock

“Nothing in biology makes sense”, wrote the evolutionary biologist Theodosius Dobzhansky, “except in the light of evolution”. If we want to assess whether it is likely that technological civilizations have evolved on alien planets or moons, and what they might be like, the theory of evolution is our best guide. On May 18, 2016 the newly founded METI (Messaging to ExtraTerrestrial Intelligence) International hosted a workshop entitled ‘The Intelligence of SETI: Cognition and Communication in Extraterrestrial Intelligence’. The workshop was held in San Juan, Puerto Rico on the first day of the National Space Society’s International Space Development Conference. It included nine talks by scientists and scholars in evolutionary biology, psychology, cognitive science, and linguistics.

METI International
METI International

In the first instalment of this series, we saw that intelligence, of various sorts, is widespread across the animal kingdom. Workshop presenter Anna Dornhaus, who studies collective decision-making in insects as an associate professor at the University of Arizona, showed that even insects, with their diminutive brains, exhibit a surprising cognitive sophistication. Intelligence, of various sorts, is a likely and probable evolutionary product.

Animals evolve the cognitive abilities that they need to meet the demands of their own particular environments and lifestyles. Sophisticated brains and cognition have evolved many times on Earth, in many separate evolutionary lineages. But, of the millions of evolutionary lineages that have arisen on Earth in the 600 million years since complex life appeared, only one, that which led to human beings, produced the peculiar combination of cognitive traits that led to a technological civilization. What this tells us is that technological civilization is not the inevitable product of a long term evolutionary trend, it is rather the quirky and contingent product of particular circumstances. But what might those circumstances have been, and just how special and improbable were they?

Geoffrey Miller
Dr. Geoffery Miller is an associate professor of psychology at the University of New Mexico, and is the author of a 2001 book, The Mating Mind, where he explains his theory that human intelligence evolved by sexual selection to a general audience. He presented at the METI Institute conference in Puerto Rico, in May 2016. Picture used with permission.

Workshop presenter Geoffrey Miller is an associate professor of psychology at the University of New Mexico. Miller thinks he has an answer to the question of what the special circumstances that produced human evolution were. Our protohuman ancestors inhabited the African savanna. But so do many other mammals that don’t need enormous brains to survive there. The evolutionary forces driving the production of our large brains, Miller surmises, can’t be due to the challenges of survival. He thinks instead that human evolution was guided by an intelligence. But Miller is no creationist, nor does he have the alien monolith from the 1960’s science fiction classic 2001: A Space Odyssey in mind. Miller’s guiding intelligence is the intelligence that our ancestors themselves used when they selected their mates.

Miller’s theory harkens back to the ideas of the founder of modern evolutionary theory, the nineteenth century British naturalist Charles Darwin. Darwin proposed that evolution works through a process of natural selection. Animal offspring vary one from another, and are produced in too great of numbers for all of them to survive. Some starve, some are eaten by predators, others fall prey to the numerous other hazards of the natural world. A few survive to produce offspring, thereby passing on the traits that allowed them to survive. Down the generations, traits that aided survival become more elaborate and useful and traits that did not, vanished.

Charles Darwin
Charles Darwin published his theory of evolution, in his book, The Origin of Species, in 1859. The theory was inspired, in part, by observations he made during his five year voyage as a naturalist on board the HMS Beagle and has become the central principle of much of modern biology. Picture by George Richmond (1830’s) public domain.

But Darwin was troubled by a serious problem with his theory. He knew that many animals have prominent traits that don’t seem to contribute to their survival, and are even counterproductive to it. The bright colors of many insects, the colors, elaborate plumage, and songs of birds, the huge antlers of elk, were all prominent and costly traits that couldn’t be explained by his theory of natural selection. Peacocks, with their elaborate tail feathers were everywhere in English gardens, and came to torment him.

At last, Darwin found the solution. To produce offspring, an animal must do more than just survive, it must find a partner to mate with. All the traits which worried Darwin could be explained if they served to make their bearers sexier and more beautiful to prospective mates than other competing members of their own gender. If peahens like elaborate plumage, then in each generation, they will choose to mate with the males with the most elaborate tail feathers, and reject the rest. Through the competition for mates, peacock tails will become more and more elaborate down the generations. Darwin called his new theory sexual selection.

Many subsequent evolutionary biologists regarded sexual selection as of limited importance, and lumped it in with natural selection, which was said to favor traits conducive to survival and reproductive success. However, in recent decades evolutionary biologists have come to view sexual selection in a much more favorable light. Geoffrey Miller proposed that the human brain evolved through sexual selection. Human beings, he supposes, are sapiosexual; that is, they are sexually attracted by intelligence and its products. The preference for selecting intelligent mates produced greater intelligence, which in turn allowed our ancestors to become more discerning in selecting more intelligent mates, producing a kind of amplifying feedback loop, and an explosion of intelligence.

On this account, language, music, dancing, humor, art, literature, and perhaps even morality and ethics exist because those who were good at them were deemed sexier, or more trustworthy and reliable, and were thus more successful in securing mates than those who weren’t. The elaborate human brain is like the elaborate peacock’s tail. It exists for wooing mates and not for survival. There are some important ways in which protohumans were different from peafowl. Both males and females are choosy and both have large brains. Protohumans, unlike peafowl, probably formed monogamous pair bonds. Miller’s theory has complexities that space won’t permit us to explore here. To show that his theory can work, Miller needed to develop a computer model.

Human evolution
The evolution of protohuman intelligence through geography and time. Homo egaster lived in the early Pleistocene between 1.9 and 1.4 million years ago and had a brain about half the size of modern Homo sapiens. It developed advanced stone tools, and may have domesticated fire. It was closely related to Homo erectus. Homo antecessor lived from 1.2 million to 800,000 years ago and spread from Africa into Europe. It’s brain was also about half as large as that of ours. Homo rhodesiensis lived about 120,000 to 300,000 years ago. Our species, Homo sapiens, arose in Africa about 200,000 years ago and spread throughout much of the world. Homo neanderthalensis had a brain capacity somewhat larger than that of modern humans, and its larger eye sockets suggest keener vision. They disappeared about 30,000 years ago, and may have died out, in part, through competition with Homo sapiens and cooling of the climate. Public Library of Science 2003.

If Miller is right, then just how probable is the evolution of a technological civilization, and how likely is it that we will find them elsewhere in the galaxy? Miller thinks that if complex life exists on other planets or moons, it is likely to evolve reproduction through sex, just as has happened here on Earth. For complex organisms that depend on a large and complicated body of genetic information, most mutations will be neutral or harmful. In sexual reproduction half the genes of one’s offspring come from each parent. Without this mixing of genes from other individuals, asexual lineages are likely to falter and go extinct due to an accumulation of harmful mutations. Unless sexually reproducing creatures choose their mates purely at random, sexual selection is an inevitability. So, the basic conditions for runaway sexual selection to produce a brain suited to language and technology probably exists on other worlds with complex life.

One problem, though, that Anna Dornhaus pointed out, is that in sexual selection, the trait that gets exaggerated is essentially arbitrary. There are many bird species with elaborate plumage, but none exactly like the peacock. There are many species where brains and cognitive traits matter for mating success, like the singing ability of nightingales and many other birds, or gibbons, or whales. Male bower birds build complicated structures, called bowers, out of found items, like sticks and leaves and stones and shells, to attract a female. Chimpanzees engage in complex power struggles that involve negotiation, grooming, and fighting their way to the top.

But despite the selective success of cognition and braininess in many species, our specific human sort of intelligence, with language and technology, has happened only once on Earth, and therefore might be rare in the universe. If our ancestors had found big noses rather than big brains sexy, then we might now have enormous noses rather than enormous radio telescopes capable of signaling to other worlds.

Miller is more optimistic. “It’s a rare accident” he writes, in the sense that mate preferences only rarely turn ‘sapiosexual’, focused so heavily on conspicuous displays of general intelligence… On the other hand, I think it’s likely that in any biosphere, sexual selection would eventually stumble into sapiosexual mate preferences, and then you’d get human-level intelligence and language of some sort. It might only arise in 1 out of every 100 million species though,…I suspect that in any biosphere with sexually reproducing complex organisms and a wide variety of species, you’d quite likely get at least one lineage stumbling into the sapiosexual niche within a billion years”.

A planet or moon is currently deemed potentially habitable if it orbits its parent star within the right distance range for liquid water to exist on its surface. This distance range is called the habitable zone. Since stars evolve with time, the duration of habitability is limited. Such matters can be explored through climate modeling, informed by what we know of the climates of Earth and other worlds within our solar system, and about the evolution of stars.

Current thinking is that Earth’s total duration of habitability is 6.3 to 7.8 billion years, and that our world may remain habitable for another 1.75 billion years. Since complex life has already existed on Earth for 600 million years, this seems a generous amount of time for complex life on a similar planet to stumble upon Miller’s sapiosexual niche. Stars of smaller mass than the sun are stable on longer timescales, some perhaps capable of sustaining worlds with liquid water for a hundred billion years. If Miller’s estimates are reasonable, then there may be worlds enough and time for an abundance of sapiosexual alien civilizations in our galaxy.

A central message of the METI Institute workshop is that, animals evolve whatever sort of intelligence is necessary for them to survive and reproduce under the circumstances in which they find themselves. Human-style intelligence, with language and technology, is a peculiar quirk of particular and improbable evolutionary circumstances. But we don’t know just how improbable. Given the vastness of time and number of worlds potentially available for the roll of the evolutionary dice, alien civilizations might be reasonably abundant, or they might be once-in-a-billion galaxies rare. We just don’t know. Better knowledge of the evolution of life and intelligence here on Earth might allow us to improve our estimates.

If alien civilizations do exist, what can life on Earth tell us about what their minds and senses are likely to be like? Are they, like us, visually oriented creatures, or might they rely on other senses? Can we expect that their minds might be similar enough to ours to make meaningful communication possible? These intriguing questions will be the subject of the third and final installment of this series.

For further reading:

Hooper, P. L. (2008) Mutual mate choice can drive costly signalling even under perfect monogamy. Adaptive Behavior, 16: p. 53-70.

Marris, E. (2013) Earth’s days are numbered. Nature News.

Miller, G. F. (2000) The Mating Mind: How Sexual Choice Shaped the Evolution of Human Nature. Random House, New York.

Miller, G. F. (2007) Sexual selection for moral virtues, The Quarterly Review of Biology, 82(2): p. 97-125.

Patton, P. E. (2016) Alien Minds I: Are Extraterrestrial Civilizations Likely to Evolve? Universe Today.

P. Patton (2014) Communicating across the cosmos, Part 1: Shouting into the darkness, Part 2: Petabytes from the Stars, Part 3: Bridging the Vast Gulf, Part 4: Quest for a Rosetta Stone, Universe Today.

Rushby, A. J., Claire, M. W., Osborn, H., Watson, A. J. (2013) Habitable zone lifetimes of exoplanets around main sequence stars. Astrobiology, 13(9), p. 833-849.

Yirka, B. (2016) Yeast study offers evidence of the superiority of sexual reproduction versus cloning in speed of adaptation. Phys.org.

Alien Minds I: Are Extraterrestrial Civilizations Likely to Evolve?

The face of a jumping spider

Is it likely that human level intelligence and technological civilization has evolved on other worlds? If so, what kinds of sensory and cognitive systems might extraterrestrials have? This was the subject of the workshop ‘The Intelligence of SETI: Cognition and Communication in Extraterrestrial Intelligence’ held in Puerto Rico on May 18, 2016. The conference was sponsored by the newly founded METI International (Messaging to ExtraTerrestrial Intelligence). One of the organization’s central goals is to build an interdisciplinary community of scholars concerned with designing interstellar messages that can be understood by non-human minds.

METI International
METI International


At present, the only clues we have to the nature of extraterrestrial minds and perception are those that can be garnered by a careful study of the evolution of mind and perception here on Earth. The workshop included nine speakers from universities in the United States and Sweden, specializing in biology, psychology, cognitive science, and linguistics. It had sessions on the evolution of cognition and the likely communicative and cognitive abilities of extraterrestrials.

Doug Vakoch, a psychologist and the founder and president of METI International, notes that astronomers and physicists properly concern themselves largely with the technologies needed to detect alien intelligence. However, finding and successfully communicating with aliens may require attention to the evolution and possible nature of alien intelligence. “The exciting thing about this workshop”, Vakoch writes, “is that the speakers are giving concrete guidelines about how to apply insights from basic research in biology and linguistics to constructing interstellar messages”. In this, the first installment dealing with the conference, we’ll focus on the question of whether the evolution of technological societies on other planets is likely to be common, or rare.

Doug Vakoch, President METI Institute
Dr. Douglas Vakoch is a Professor of clinical psychology and the founder and president of METI International. Photo by Mara Lavitt, used with permission.

We now know that most stars have planets, and rocky planets similar to or somewhat larger than the Earth or Venus are commonplace. Within this abundant class of worlds, there are likely to be tens of billions with conditions suitable for sustaining liquid water on their surfaces in our galaxy. We don’t yet know how likely it is that life will arise on such worlds. But suppose, as many scientists suspect, that simple life is abundant. How likely is it that alien civilizations will appear; civilizations with which we could communicate and exchange ideas, and which could make their presence known to us by signaling into space? This was a central question explored at the conference.

In addressing such questions, scientists have two main sets of clues to draw on. The first comes from the study of the enormous diversity of behavior and nervous and sensory systems of the animal species that inhabit our Earth; an endeavor that has been called cognitive ecology. The second set of clues come from modern biology’s central principle; the theory of evolution. Evolutionary theory can provide scientific explanations of how and why various senses and cognitive systems have come to exist here on Earth, and can guide our expectations about what might exist elsewhere.

Artist's impression of three newly-discovered exoplanets orbiting an ultracool dwarf star TRAPPIST-1. Credit: ESO/M. Kornmesser/N. Risinger (skysurvey.org).
Artist’s impression of three newly-discovered exoplanets orbiting an ultracool dwarf star TRAPPIST-1. Credit: ESO/M. Kornmesser/N. Risinger (skysurvey.org).
The basics of the electrochemical signalling that make animal nervous systems possible have deep evolutionary roots. Even plants and bacteria have electrochemical signalling systems that share some basic features with those in our brains. Conference presenter Dr. Anna Dornhaus studies how social insects make decisions collectively as an associate professor at the University of Arizona. She defines cognitive ability as the ability to solve problems with a nervous system, and sometimes also by social cooperation. An animal is more ‘intelligent’ if its problem solving abilities are more generalized. Defined this way, intelligence is widespread among animals. Skills traditionally thought to be the sole province of primates (monkeys and apes, including human beings) have now been shown to be surprisingly common.
Dr. Anna Dornhaus
Dr. Anna Dornhaus is an Associate Professor of Ecology and Evolutionary Biology at the University of Arizona, and a presenter at the Puerto Rico conference

For example, cognitive skills like social learning and teaching, generalizing from examples, using tools, recognizing individuals of one’s species, making plans, and understanding spatial relationships have all been shown to exist in arthropods (an animal group consisting of insects, spiders, and crustaceans). The evidence shows the surprising power of the diminutive brains of insects, and indicates that we know little of the relationship between brain size and cognitive ability.

But different animals often have different sets of cognitive skills, and if a species is good at one cognitive skill, that doesn’t necessarily mean it will be good at others. Human beings are special, not because we have some specific cognitive ability that other animals lack, but because we possess a wide range of cognitive abilities that are more exaggerated and highly developed than in other animals.

The cathedral termite mound
Termite mounds demonstrate that architecture and agriculture are not unique to humans. Housing one to two million inhabitants, they can reach 5 meters (17 feet) or more in height, and also extend beneath the surface of the ground. They are organized to ensure that appropriate levels of oxygen, moisture, and temperature are maintained. Although the inhabitants of a termite mound collectively weigh only 15 kilograms (33 lb), a typical mound will, in an average year, move a quarter of a metric ton (550 lb) of soil, and several tons of water. Using carefully prepared plant materials, termites “farm” a species of fungus that occupies eight times more space in the mound than they do. Photo taken by Brain Voon Yee Yap of cathedral termite mounds in the Northern Territories of Australia for open use.

Although the Earth, as a planet, has existed for 4.6 billion years, complex animals with hard body parts don’t appear in the fossil record until 600 million years ago, and complex life didn’t appear on land until about 400 million years ago. Looking across the animal kingdom as a whole, three groups of animals, following separate evolutionary paths, have evolved especially complex nervous systems and behaviors. We’ve already mentioned arthropods, and the sophisticated behaviors mediated by their diminutive yet powerful brains.

Molluscs, a group of animals that includes slugs and shellfish, have also produced a group of brainy animals; the cephalopods. The cephalopods include octopuses, squids, and cuttlefish. The octopus has the most complex nervous system of any animal without a backbone. As the product of a different evolutionary path, the octopus’s sophisticated brain has a plan of organization that is completely alien to that of more familiar animals with backbones.

The third group to have produced sophisticated brains are the vertebrates; animals with backbones. They include fishes, amphibians, reptiles, birds, and mammals, including human beings. Although all vertebrate brains bear a family resemblance, complex brains have evolved from simpler brains many separate times along different paths of vertebrate evolution, and each such brain has its own unique characteristics.

Along one path, birds have evolved a sophisticated forebrain, and with it, a flexible and creative capacity to make and use tools, an ability to classify and categorize objects, and even a rudimentary understanding of numbers. Following a different path, and based on a different plan of forebrain organization, mammals have also evolved sophisticated intelligence. Three groups of mammals; elephants, cetaceans (a group of aquatic mammals including dophins, porpoises, and whales), and primates (monkeys and apes, including human beings) have evolved the most complex brains on Earth.

Given the evidence that intelligent problem solving skills of various sorts have evolved many times over, along many different evolutionary pathways, in an amazing range of animal groups, one might suspect that Dornhaus believes that human-style cognitive abilities and civilizations are widespread in the universe. In fact, she doesn’t. She thinks that humans with their exaggerated cognitive abilities and unique ability to use language to express complex and novel sorts of information are a quirky and unusual fluke of evolution, and might, for all we know, be wildly improbable. Her argument that alien civilizations probably aren’t widespread resembles one stated by the imminent and influential American evolutionary biologist Ernst Mayr in his 1988 book Towards a New Philosophy of Biology.

There are currently more than 10 million different species of animals on Earth. All but one have failed to evolve the human level of intelligence. This makes the chance of evolving human intelligence less than one in 10 million. Over the last six hundred million years since complex life has appeared on Earth, there have been tens of million different animal species, each existing for roughly 1-10 million years. But, so far as we know, only one of them, Homo sapiens, ever produced a technological society. The human lineage diverged from that of other great ape species about 8 million years ago, but we don’t see evidence of distinctly human innovation until about 50,000 years ago, which is, perhaps, another indication of its rarity.

Despite the apparent improbability of human level intelligence evolving in any one lineage, Earth, as a whole, with its vast array of evolutionary lineages, has nonetheless produced a technological civilization. But that still doesn’t tell us very much. For the present, Earth is the only habitable planet that we know much of anything about. And, since Earth produced us, we are working with a biased sample. So we can’t be at all confident that the presence of human civilization on Earth implies that similar civilizations are likely to occur elsewhere.

For all we know, the quirky set of events that produced human beings might be so wildly improbable that human civilization is unique in a hundred billion galaxies. But, we don’t know for sure that alien civilizations are wildly improbable either. Dornhaus freely concedes that neither she nor anybody has a good idea of just how improbable human intelligence might be, since the evolution of intelligence is still so poorly understood.

Most current evolutionary thinking, following in the footsteps of Mayr and others, holds that human civilization was not the inevitable product of a long-term evolutionary trend, but rather the quirky consequence of a particular and improbable set of evolutionary events. What sort of events might those have been, and just how improbable were they? Dornhaus supports a popular theory proposed by Dr. Geoffrey Miller, an evolutionary psychologist who is an associate professor in the Department of Psychology at the University of New Mexico and who also spoke at the METI institute workshop.

In our next installment we’ll explore Miller’s theories in a bit more detail, and see why the abundance of extraterrestrial civilizations might depend on whether or not aliens think big brains are sexy.

For further reading:
Baluska, F. and Mancuso, S. (2009) Deep evolutionary origins of neurobiology. Communicative and Integrative Biology, 2:1, 60-65.

Chittka, L. and Niven, J. (2009) Are bigger brains better?, Current Biology. 19:21 p. R995-R1008.

Margonelli, L. (2014) Collective mind in the mound: How do termites build their huge structures. National Geographic.

Mayr, E. (1988) The probability of extraterrestrial intelligent life. In Towards a New Philosophy of Biology, Harvard University Press, Cambridge, MA.

Patton, P. E. (2015) Who speaks for Earth? The controversy over interstellar messaging. Universe Today.

P. Patton (2014) Communicating across the cosmos, Part 1: Shouting into the darkness, Part 2: Petabytes from the Stars, Part 3: Bridging the Vast Gulf, Part 4: Quest for a Rosetta Stone, Universe Today.

Tonn, S. (2015) Termites are teaching architects to design super-efficient skyscrapers. Wired Magazine.

Is There a Kraken in Kraken Mare? What Kind of Life Would We Find on Titan?

The left image shows a mosaic of images of Titan taken by the Cassini spacecraft in near infrared light. Titan’s polar seas are visible as sunlight glints off of them. The right image is a radar image of Kraken Mare. Credit: NASA Jet Propulsion Laboratory.

Could there be life on Saturn’s large moon Titan? Asking the question forces astrobiologists and chemists to think carefully and creatively about the chemistry of life, and how it might be different on other worlds than it is on Earth. In February, a team of researchers from Cornell University, including chemical engineering graduate student James Stevenson, planetary scientist Jonathan Lunine, and chemical engineer Paulette Clancy, published a pioneering study arguing that cell membranes could form under the exotic chemical conditions present on this remarkable moon.

In many ways, Titan is Earth’s twin. It’s the second largest moon in the solar system and bigger than the planet Mercury. Like Earth, it has a substantial atmosphere, with a surface atmospheric pressure a bit higher than Earth’s. Besides Earth, Titan is the only object in our solar system known to have accumulations of liquid on its surface. NASA’s Cassini space probe discovered abundant lakes and even rivers in Titan’s polar regions. The largest lake, or sea, called Kraken Mare, is larger than Earth’s Caspian Sea. Researchers know from both spacecraft observations and laboratory experiments that Titan’s atmosphere is rich in complex organic molecules, which are the building blocks of life.

All these features might make it seem as though Titan is tantalizingly suitable for life. The name ‘Kraken’, which refers to a legendary sea monster, fancifully reflects the eager hopes of astrobiologists. But, Titan is Earth’s alien twin. Being almost ten times further from the sun than Earth is, its surface temperature is a frigid -180 degrees Celsius. Liquid water is vital to life as we know it, but on Titan’s surface all water is frozen solid. Water ice takes on the role that silicon-containing rock does on Earth, making up the outer layers of the crust.

The liquid that fills Titan’s lakes and rivers is not water, but liquid methane, probably mixed with other substances like liquid ethane, all of which are gases here on Earth. If there is life in Titan’s seas, it is not life as we know it. It must be an alien form of life, with organic molecules dissolved in liquid methane instead of liquid water. Is such a thing even possible?

The Cornell team took up one key part of this challenging question by investigating whether cell membranes can exist in liquid methane. Every living cell is, essentially, a self-sustaining network of chemical reactions, contained within bounding membranes. Scientists think that cell membranes emerged very early in the history of life on Earth, and their formation might even have been the first step in the origin of life.

Here on Earth, cell membranes are as familiar as high school biology class. They are made of large molecules called phospholipids. Each phospholipid molecule has a ‘head’ and a ‘tail’. The head contains a phosphate group, with a phosphorus atom linked to several oxygen atoms. The tail consists of one or more strings of carbon atoms, typically 15 to 20 atoms long, with hydrogen atoms linked on each side. The head, due to the negative charge of its phosphate group, has an unequal distribution of electrical charge, and we say that it is polar. The tail, on the other hand, is electrically neutral.

phospholipid membrane
Here on Earth, cell membranes are composed of phospholipid molecules dissolved in liquid water. A phospholipid has a backbone of carbon atoms (gray), and also contains hydrogen (sky blue), phosphorus (yellow), oxygen (red), and nitrogen (blue). Due to the positive charge associated with the nitrogen containing choline group, and the negative charge associated with the phosphate group, the head is polar, and attracts water. It is therefore hydrophilic. The hydrocarbon tail is electrically neutral and hydrophobic. The structure of a cell membrane is due these electrical properties of phospholipids and water. The molecules form a double layer, with the hydrophilic heads facing outward, towards water, and the hydrophobic tails facing inward, towards one another. Credit: Ties van Brussel

These electrical properties determine how phospholipid molecules will behave when they are dissolved in water. Electrically speaking, water is a polar molecule. The electrons in the water molecule are more strongly attracted to its oxygen atom than to its two hydrogen atoms. So, the side of the molecule where the two hydrogen atoms are has a slight positive charge, and the oxygen side has a small negative charge. These polar properties of water cause it to attract the polar head of the phospholipid molecule, which is said to be hydrophilic, and repel its nonpolar tail, which is said to be hydrophobic.

When phospholipid molecules are dissolved in water, the electrical properties of the two substances work together to cause the phospholipid molecules to organize themselves into a membrane. The membrane closes onto itself into a little sphere called a liposome. The phospholipid molecules form a bilayer two molecules thick. The polar hydrophilic heads face outward towards the water on both the inner and outer surface of the membrane. The hydrophobic tails are sandwiched between, facing each other. While the phospholipid molecules remain fixed in their layer, with their heads facing out and their tails facing in, they can still move around with respect to each other, giving the membrane the fluid flexibility needed for life.

Phospholipid bilayer membranes are the basis of all terrestrial cell membranes. Even on its own, a liposome can grow, reproduce and aid certain chemical reactions important to life, which is why some biochemists think that the formation of liposomes might have been the first step towards life. At any rate, the formation of cell membranes must surely been an early step in life’s emergence on Earth.

water and methane
At the left, water, consisting of hydrogen (H) and oxygen (O), is a polar solvent. Oxygen attracts electrons more strongly than hydrogen does, giving the hydrogen side of the molecule a net positive charge and the oxygen side a net negative charge. The delta symbol ( ) indicates that the charge is partial, that is less than a full unit of positive or negative charge. At right, methane is a non-polar solvent, due to the symmetrical distribution of hydrogen atoms (H) around a central carbon atom (C). Credit: Jynto as modified by Paul Patton.

If some form of life exists on Titan, whether sea monster or (more likely) microbe, it would almost certainly need to have a cell membrane, just like every living thing on Earth does. Could phospholipid bilayer membranes form in liquid methane on Titan? The answer is no. Unlike water, the methane molecule has an even distribution of electrical charges. It lacks water’s polar qualities, and so couldn’t attract the polar heads of phospholipid molecule. This attraction is needed for the phospholipids to form an Earth-style cell membrane.

Experiments have been conducted where phospholipids are dissolved in non-polar liquids at Earthly room temperature. Under these conditions, the phospholipids form an ‘inside-out’ two layer membrane. The polar heads of the phospholipid molecules are at the center, attracted to one another by their electrical charges. The non-polar tails face outward on each side of the inside-out membrane, facing the non-polar solvent.

membranes in polar and non-polar solvents
At left, phospholipids are dissolved in water, a polar solvent. They form a bilayer membrane, with their polar, hydrophilic heads facing outward towards water, and their hydrophobic tails facing each other. At right, when phospholipids are dissolved in a non-polar solvent at Earthly room temperature, they form an inside-out membrane, with the polar heads attracting one another, and the non-polar tails facing outwards towards the non-polar solvent. Based on figure 2 from Stevenson, Lunine, and Clancy (2015). Credit: Paul Patton

Could Titanian life have an inside out phospholipid membrane? The Cornell team concluded that this wouldn’t work, for two reasons. The first is that at the cryogenic temperatures of liquid methane, the tails of phospholipids become rigid, depriving any inside-out membrane that might form of the fluid flexibility needed for life. The second is that two key ingredients of phospholipids; phosphorus and oxygen, are probably unavailable in the methane lakes of Titan. In their search for Titanian cell membranes, the Cornell team needed to probe beyond the familiar realm of high school biology.

Although not composed of phospholipids, the scientists reasoned that any Titanian cell membrane would nevertheless be like the inside-out phospholipid membranes created in the lab. It would consist of polar molecules clinging together electrically in a solution of non-polar liquid methane. What molecules might those be? For answers the researchers looked to data from the Cassini spacecraft and from laboratory experiments that reproduced the chemistry of Titan’s atmosphere.

Titan’s atmosphere is known to have a very complex chemistry. It is made mostly of nitrogen and methane gas. When the Cassini spacecraft analyzed its composition using spectroscopy it found traces of a variety of compounds of carbon, nitrogen, and hydrogen, called nitriles and amines. Researchers have simulated the chemistry of Titan’s atmosphere in the lab by exposing mixtures of nitrogen and methane to sources of energy simulating sunlight on Titan. A stew of organic molecules called ‘tholins’ is formed. It consists of compounds of hydrogen and carbon, called hydrocarbons, as well as nitriles and amines.

The Cornell investigators saw nitriles and amines as potential candidates for their Titanian cell membranes. Both are polar molecules that might stick together to form a membrane in non-polar liquid methane due to the polarity of nitrogen containing groups found in both of them. They reasoned that candidate molecules must be much smaller than phospholipids, so that they could form fluid membranes at liquid methane temperatures. They considered nitriles and amines containing strings of between three and six carbon atoms. Nitrogen containing groups are called ‘azoto’ –groups, so the team named their hypothetical Titanian counterpart to the liposome the ‘azotosome’.

Synthesizing azotosomes for experimental study would have been difficult and expensive, because the experiments would need to be conducted at the cryogenic temperatures of liquid methane. But since the candidate molecules have been studied extensively for other reasons, the Cornell researchers felt justified in turning to the tools of computational chemistry to determine whether their candidate molecules could cohere as a flexible membrane in liquid methane. Computational models have been used successfully to study conventional phospholipid cell membranes.

acrylonitrile
Acrylonitrile has been identified as a possible basis for cell membranes in liquid methane on Titan. It is known to be present in Titan’s atmosphere at a concentration of 10 parts per million and has been produced in laboratory simulations of the effects of energy sources on Titan’s nitrogen-methane atmosphere. As a small polar molecule capable of dissolving in liquid methane, it is a candidate substance for the formation of cell membranes in an alternative biochemistry on Titan. Light blue: carbon atoms, dark blue: nitrogen atom, white: hydrogen atoms. Credit: Ben Mills as modified by Paul Patton.

acrylonitrile membrane
Polar acrylonitrile molecules align ‘head’ to ‘tail’ to form a membrane in non-polar liquid methane. Light blue: carbon atoms, dark blue: nitrogen atoms, white: hydrogen atoms. Credit: James Stevenson.

The group’s computational simulations showed that some candidate substances could be ruled out because they would not cohere as a membrane, would be too rigid, or would form a solid. Nevertheless, the simulations also showed that a number of substances would form membranes with suitable properties. One suitable substance is acrylonitrile, which Cassini showed is present in Titan’s atmosphere at 10 parts per million concentration. Despite the huge difference in temperature between cryogenic azotozomes and room temperature liposomes, the simulations showed them to exhibit strikingly similar properties of stability and response to mechanical stress. Cell membranes, then, are possible for life in liquid methane.

azotosome
Computational chemistry simulations show that acrylonitrile and some other small polar nitrogen containing organic molecules are capable of forming ‘azotosomes’ when they are dissolved on liquid methane. Azotosomes are small membrane bounded spherules like the liposomes formed by phospholipids when they are dissolved in water. The simulations show that acrylonitrile azotosomes would be both stable and flexible in cryogenically cold liquid methane, giving them the properties they need to function as cell membranes for hypothetical Titanian life, or for life on any world with liquid methane on its surface. The azotosome shown is 9 nanometers in size, about the size of a virus. Light blue: carbon atoms, dark blue: nitrogen atoms, white: hydrogen atoms. Credit: James Stevenson.

The scientists from Cornell view their findings as nothing more than a first step towards showing that life in liquid methane is possible, and towards developing the methods that future spacecraft will need to search for it on Titan. If life is possible in liquid methane, the implications ultimately extend far beyond Titan.

When seeking conditions suitable for life in the galaxy, astronomers typically search for exoplanets within a star’s habitable zone, defined as the narrow range of distances over which a planet with an Earth-like atmosphere would have a surface temperature suitable for liquid water. If methane life is possible, then stars would also have a methane habitable zone, a region where methane could exist as a liquid on a planet or moon, making methane life possible. The number of habitable worlds in the galaxy would be greatly increased. Perhaps, on some worlds, methane life evolves into complex forms that we can scarcely imagine. Maybe some of them are even a bit like sea monsters.

References and Further Reading:

N. Atkinson (2010) Alien Life on Titan? Hang on Just a Minute, Universe Today.

N. Atkinson (2010) Life on Titan Could be Smelly and Explosive, Universe Today.

M. L. Cable, S. M. Horst, R. Hodyss, P. M. Beauchamp, M. A. Smith, P. A. Willis, (2012) Titan tholins: Simulating Titan organic chemistry in the Cassini-Huygens era, Chemical Reviews, 112:1882-1909.

E. Howell (2014) Titan’s Majestic Mirror-Like Lakes Will Come Under Cassini’s Scrutiny This Week, Universe Today.

J. Major (2013) Titan’s North Pole is Loaded With Lakes, Universe Today.

C. P. McKay, H. D. Smith, (2005) Possibilities for methanogenic life in liquid methane on the surface of Titan, Icarus 178: 274-276.

J. Stevenson, J. Lunine, P. Clancy, (2015) Membrane alternatives in worlds without oxygen: Creation of an azotosome, Science Advances 1(1):e1400067.

S. Oleson (2014) Titan submarine: Exploring the depths of Kraken, NASA Glenn Research Center, Press release.

Cassini Solstice Mission, NASA Jet Propulsion Laboratory

NASA and ESA celebrate 10 years since Titan landing, NASA 2015

Beyond “Fermi’s Paradox” II: Questioning the Hart-Tipler Conjecture

It’s become a legend of the space age. The brilliant physicist Enrico Fermi, during a lunchtime conversation at Los Alamos National Laboratory in 1950, is supposed to have posed a conundrum for proponents of the existence of extraterrestrial civilizations.

If space traveling aliens exist, so the argument goes, they would spread through the galaxy, colonizing every habitable world. They should then have colonized Earth. They should be here, but because they aren’t, they must not exist.

This is the argument that has come to be known as “Fermi’s paradox”. The problem is, as we saw in the first installment, Fermi never made it. As his surviving lunch companions recall (Fermi himself died of cancer just four years later, and never published anything on the topic of extraterrestrial intelligence), he simply raised a question, “Where is everybody?” to which there are many possible answers.

Fermi didn’t doubt that extraterrestrial civilizations might exist, but supposed that interstellar travel wasn’t feasible or that alien travelers had simply never found Earth in the vastness of the galaxy.

The argument claiming that extraterrestrials don’t exist was actually proposed by the astronomer Michael Hart, in a paper he published in 1975. Hart supposed that if an extraterrestrial civilization arose in the galaxy it would develop interstellar travel and launch colonizing expeditions to nearby stars. These colonies would, in turn, launch their own starships spreading a wave of colonization across the galaxy.

How long would the wave take to cross the galaxy? Assuming that the starships traveled at one tenth the speed of light and that no time was lost in building new ships upon arriving at the destination, the wave, Hart surmised, could cross the galaxy in 650,000 years.

Even allowing for a modicum of time for each colony to establish itself before building more ships, the galaxy could be crossed in two million years, a miniscule interval on a cosmic or evolutionary timescale. Hart asserted that because extraterrestrials aren’t already here on Earth, none exist in our galaxy.

Hart’s argument was extended by cosmologist Frank Tipler in 1980. Tipler supposed that alien colonists would be assisted by self-reproducing robots. His conclusion was announced in the title of his paper ‘Extraterrestrial intelligent beings do not exist’.

Why is it important that Hart’s argument wasn’t really also formulated by the eminent Enrico Fermi? Because Fermi’s name lends a credibility to the argument that it might not deserve. Supporters of the search for extraterrestrial intelligence (SETI) want to search for evidence that alien civilizations exist by using radio telescopes to listen for radio messages that extraterrestrials may have transmitted into space. Interstellar signaling is vastly cheaper than a starship, and is feasible with technology we have today.

Hart drew public policy consequences from his argument that extraterrestrials don’t exist. His paper concluded that “an extensive search for radio messages from other civilizations is probably a waste of time and money”.

Our political leaders heeded Hart’s advice. When Senator William Proxmire led the successful drive to kill funding for NASA’s fledgling SETI program in 1981, he used the Hart-Tipler argument. A second NASA SETI effort was scuttled by congress in 1993, and no public money has been allocated to the search for extraterrestrial radio signals ever since.

The Arecibo Radio Telescope in Puerto Rico was the site of NASA's High Resolution Microwave Survey, a search for extraterrestrial radio messages.  Funding was cut off for the project in 1993 following criticism in congress.  Credit: Unites States National Science Foundation
The Arecibo Radio Telescope in Puerto Rico was the site of NASA’s High Resolution Microwave Survey, a search for extraterrestrial radio messages. Funding was cut off for the project in 1993 following criticism in congress. Credit: Unites States National Science Foundation

Just how convincing is the Hart-Tipler conjecture? Like Hart, Carl Sagan was an optimist about the prospects for interstellar travel, and Sagan published his analysis of the consequences of interstellar travel for extraterrestrial intelligence a whole decade earlier than Hart, in 1963. Sagan and his co-author, the Russian astronomer Iosef Shklovskii devoted a chapter to the topic in their 1966 classic Intelligent Life in the Universe.

Like Hart, Sagan concluded that “if colonization is the rule, then even one spacefaring civilization would rapidly spread, in a time much shorter than the age of the galaxy, throughout the Milky Way. There would be colonies of colonies of colonies…”. So why didn’t Sagan, like Hart, assert that extraterrestrials don’t exist because they aren’t already here?

The answer is that Sagan, unlike Hart, considered unlimited colonization as only one of many possible ways that extraterrestrial spacefarers might act. He wrote that “habitable planets lacking technical civilizations will frequently be encountered by spacefaring civilizations. It is not clear what their response will be…Perhaps strict injunctions against colonization of populated but pre-technical planets are in effect in some Codex Galactica. But we are in no position to judge extraterrestrial ethics. Perhaps attempts are made to colonize every habitable planet…A whole spectrum of intermediate cases can also be imagined”.

Besides assuming that interstellar travel is feasible, Hart’s argument is based on very specific and highly speculative ideas about how extraterrestrials must behave. He assumed that they would pursue a policy of unlimited expansion, that they would expand quickly, and that once their colonies were established, they would last for millions or even billions of years. If any of his speculations about how extraterrestrials will act aren’t right, then his argument that they don’t exist fails.

The evolutionary biologist Stephen Jay Gould was scathing in his criticism of Hart’s speculation. He wrote that ”I must confess that I simply don’t know how to react to such arguments. I have enough trouble predicting the plans and reactions of the people closest to me. I am usually baffled by the thoughts and accomplishments of humans in different cultures. I’ll be damned if I can state with certainty what some extraterrestrial source of intelligence might do”.

In 1981, Sagan and planetary scientist William Newman published a response to Hart and Tipler. While Hart used a very simple mathematical argument, assuming that an alien civilization would spread almost as fast as its ships could travel, Newman and Sagan used a mathematical model like the ones that population biologists use to analyze the spread of animal populations to model interstellar colonization.

They concluded that the rates of expansion assumed by Hart are highly unrealistic. Expansion will be drastically slower, for example, if civilizations control their population growth rates on any given planet to avoid ecological collapse, if colonies have a finite life span, and if alien societies eventually outgrow expansionist tendencies. Hart’s assumption that an alien civilization would spread almost as fast as its ships can travel isn’t plausible. It’s possible to walk across Rome in a day, Newman and Sagan noted, but Rome wasn’t built in a day. It grew much more slowly.

If the evolution of intelligent life is at all likely, other civilizations could emerge before any hypothetical first wave of expansion swept slowly over the galaxy. If several worlds produced waves of colonization, they might encounter one another. What would happen then? Nobody knows. The history of the galaxy can’t be predicted from a few equations.

For Newman and Sagan, the absence of extraterrestrials on Earth doesn’t mean that they don’t exist elsewhere in the galaxy, or that they never launch starships. It just means that they don’t behave in the way Hart expected. They conclude that “except possibly in the very early history of the Galaxy, there are no very old galactic civilizations with a consistent policy of conquest of inhabited worlds; there is no Galactic Empire”.

So, Enrico Fermi never did produce a powerful argument that extraterrestrial intelligence probably doesn’t exist. Neither did Michael Hart. The simple truth is that nobody knows whether or not extraterrestrials exist in the galaxy. If they do exist though, it’s possible that discovering their radio messages would give us the evidence we need. Then we could stop speculating and start learning something.

References and Further Reading:

F. Cain (2013) Where are all the aliens? The Fermi paradox, Universe Today.

F. Cain (2014) Are intelligent civilizations doomed? Universe Today.

R. H. Gray (2012) The Elusive WOW, Searching for Extraterrestrial Intelligence, Palmer Square Press, Chicago, Illinois.

R. H. Gray (2015) The Fermi Paradox is neither Fermi’s nor a paradox, Astrobiology, 15(3): 195-199.

M. H. Hart, (1975) An explanation for the absence of extraterrestrials on Earth, Quarterly Journal of the Royal Astronomical Society, 16:128-135.

W. I. Newman and C. Sagan (1981) Galactic civilizations: Population dynamics and interstellar diffusion, Icarus, 46:293-327.

C. Sagan (1963) Direct contact among galactic civilizations by relativistic interstellar spaceflight, Planetary and Space Science, 11:485-489.

I. S. Shklovskii and C. Sagan (1966) Intelligent Life in the Universe. Delta Publishing Company, Inc. New York, NY.

F. Tipler (1980) Extraterrestrial intelligent beings do not exist, Quarterly Journal of the Royal Astronomical Society, 21:267-281.

S. Webb (2010) If the Universe is Teeming with Aliens…Where is Everybody? Fifty Solutions to the Fermi Paradox and the Problem of Extraterrestrial Life. Copernicus Books, New York, NY.

Beyond “Fermi’s Paradox” I: A Lunchtime Conversation- Enrico Fermi and Extraterrestrial Intelligence

It’s become a kind of legend, like Newton and the apple or George Washington and the cherry tree. One day in 1950, the great physicist Enrico Fermi sat down to lunch with colleagues at the Fuller Lodge at Los Alamos National Laboratory in New Mexico and came up with a powerful argument about the existence of extraterrestrial intelligence, the so-called “Fermi paradox”. But like many legends, it’s only partly true. Robert Gray explained the real history in a recent paper in the journal Astrobiology.

Enrico Fermi was the winner of the 1938 Nobel Prize for physics, led the team that developed the world’s first nuclear reactor at the University of Chicago, and was a key contributor to the Manhattan Project that developed the atomic bomb during World War II. The Los Alamos Lab where he worked was founded as the headquarters of that project.

The line of reasoning often attributed to Fermi, in his lunchtime conversation, runs like this: There may be many habitable Earth-like planets in our Milky Way galaxy. If intelligent life and technological civilization arise on any one of them, that civilization will eventually invent a means of interstellar travel. It will colonize nearby stellar systems. These colonies will send out their own colonizing expeditions, and the process will continue inevitably until every habitable planet in the galaxy has been reached.

The fact that there aren’t already aliens here on Earth was therefore supposed to be strong evidence that they don’t exist anywhere in the galaxy. This argument actually isn’t Fermi’s and was published more than 25 years later by astronomer Michael Hart. It was elaborated in a paper published by the cosmologist Frank Tipler in 1980.

Fermi’s lunch conversation really did happen. Although he died just four years later of cancer, physicist Eric Jones published the recollections of the physicist’s luncheon companions more than thirty five years later. Among these companions were Edward Teller, Emil Konopinski, and Herbert York, all eminent physicists and veterans of the Manhattan Project. Teller played a central role in the development of the hydrogen bomb. Konopinski studied the structure of the atomic nucleus, and York became director of Lawrence Livermore National Laboratory.

Edward Teller was the head of the Theoretical Physics Division at Los Alamos National Laboratory during the Manhattan Project that developed the atomic bomb for World War II. After the war he was central to the development of the hydrogen bomb.
Edward Teller headed a group in the Theoretical Physics Division at Los Alamos National Laboratory during the Manhattan Project that developed the atomic bomb for World War II. After the war he was central to the development of the hydrogen bomb. He was one of Enrico Fermi’s lunch companions when he posed the famed question”Where is everybody?” Credit: Lawrence Livermore National Laboratory

During the walk to the Fuller Lodge, the physicists discussed a recent spate of UFO sightings, and a cartoon in the New Yorker Magazine depicting aliens and a flying saucer. Although the topic of conversation moved on as the group sat down for lunch, Edward Teller recalls “in the middle of the conversation, Fermi came out with the quite unexpected question ‘Where is everybody?’…The result of his question was general laughter because of the strange fact that in spite of Fermi’s question coming out of the clear blue, everybody around the table seemed to understand at once that he was talking about extraterrestrial life”.

In his account of the famed luncheon, Teller wrote “I do not believe much came from this conversation, except perhaps a statement that the distances to the next location of living beings may be very great and that, indeed, as far as our galaxy is concerned, we are living somewhere in the sticks, far removed from the metropolitan area of the galactic center”.

York recalled a somewhat more expansive discussion in which Fermi “followed up with a series of calculations on the probability of earthlike planets, the probability of life given an earth, the probability of humans given life, the likely rise and duration of high technology, and so on. He concluded on the basis of these calculations that we ought to have been visited long ago and many times over”.

According to York, Fermi supposed the reason we hadn’t been visited “might be the interstellar flight is impossible, or if it is possible, always judged not worth the effort, or technological civilization doesn’t last long enough for it to happen”.

So Fermi, unlike Hart, wasn’t skeptical about the existence of extraterrestrials, and didn’t view their absence from Earth as paradoxical. There is no Fermi paradox, there is simply Fermi’s question “Where is everybody?”, to which there are many possible answers. The answer that Fermi preferred seems to be that, either interstellar travel isn’t feasible because of the enormous distances involved, or Earth simply had never been reached by alien travelers.

Herbert York was a Manhattan Project physicist, the co-discoverer of the neutral pi meson, and the first director of the Lawrence Livermore National Laboratory.  He was one of Fermi's lunch companions the day he posed his famed question about extraterrestrials.  Credit: National Nuclear Security Administration
Herbert York was a Manhattan Project physicist, the co-discoverer of the neutral pi meson, and the first director of the Lawrence Livermore National Laboratory. He was one of Fermi’s lunch companions the day he posed his famed question about extraterrestrials. Credit: National Nuclear Security Administration

Interstellar distances are truly vast. If the entire solar system out to the orbit of Neptune were reduced to the size of an American quarter, the nearest star, Proxima Centauri, would still be about the length of a football field away. A practical starship would either need to travel very fast, at an appreciable fraction of the speed of light, or be capable of supporting its crew for a very long time. While either is theoretically possible, interstellar travel seems to present day humanity to be such a grandiose undertaking that it’s not clear whether any civilization would be able or willing to muster the enormous resources needed.

Where did the confusing of Fermi’s question with Hart’s argument come from? Carl Sagan mentioned Fermi’s question in a footnote to a 1963 paper. After the publication of Hart’s paper in 1975, Fermi’s question and Hart’s speculative answer became associated in many writer’s minds. Fermi’s question seemed to beg Hart’s answer, and “Fermi’s paradox” was born. According to Robert Gray, the term was coined by D. G. Stephenson, in a paper published two years after Hart’s.

Why is it important that Hart’s argument was never really made by the eminent physicist Enrico Fermi? Did Michael Hart and Frank Tipler really make a compelling case that extraterrestrial civilizations don’t exist in our galaxy? We’ll answer those questions in the second installment.

References and Further Reading:

F. Cain (2013) How Could We Find Aliens? The Search for Extraterrestrial Intelligence (SETI). Universe Today.

R. H. Gray (2012) The Elusive WOW, Searching for Extraterrestrial Intelligence, Palmer Square Press, Chicago, Illinois.

R. H. Gray (2015) The Fermi Paradox is neither Fermi’s nor a paradox, Astrobiology, 15(3): 195-199.

M. H. Hart, (1975) An explanation for the absence of extraterrestrials on Earth, Quarterly Journal of the Royal Astronomical Society, 16:128-135.

E. M. Jones (1985) “Where is everybody?” An account of Fermi’s question, Los Alamos National Laboratory.

P. Patton (2014) Communicating Across the Cosmos, Part 1, Part 2, Part 3, Part 4. Universe Today.

F. Tipler (1980) Extraterrestrial intelligent beings do not exist, Quarterly Journal of the Royal Astronomical Society, 21:267-281.

S. Webb (2010) If the Universe is Teeming with Aliens…Where is Everybody? Fifty Solutions to the Fermi Paradox and the Problem of Extraterrestrial Life. Copernicus Books, New York, NY.

Helicopter Drones on Mars

Mars helicopter drone

NASA’s Jet Propulsion Laboratory recently announced that it is developing a small drone helicopter to scout the way for future Mars rovers. Why would Mars rovers need such a robotic guide? The answer is that driving on Mars is really hard.

Here on Earth, robots exploring volcanic rims, or assisting rescuers, can be driven by remote control, with a joystick. This is because radio signals reach the robot from its control center almost instantly. Driving on the moon isn’t much harder. Radio signals traveling at the speed of light take about two and half seconds to make the round trip to the moon and back. This delay isn’t long enough to seriously interfere with remote control driving. In the 1970’s Soviet controllers drove the Lunokhod moon rovers this way, successfully exploring more than 40 km of lunar terrain.

Driving on Mars is much harder, because it is so much further away. Depending on its position with respect to Earth, signals can take between 8 and 42 minutes for the round trip. Pre-programmed instructions must be sent to the rover, which it then executes on its own. Each Martian drive takes hours of careful planning. Stereo images taken by the rover’s navigation cameras are carefully scrutinized by engineers. Images from spacecraft orbiting Mars sometimes provide additional information.

A rover can be programmed either to simply execute a list of driving commands sent from Earth, or it can use images taken by its navigation cameras and processed by its on-board computers to measure speed and detect obstacles or hazards by itself. It can even plot its own safe path to a specified goal. Drives based on instructions from the ground are the fastest.

The Mars Exploration Rovers Spirit and Opportunity could drive up to 124 meters in an hour this way. This corresponds to about the length of an American football field. But this mode was also the least safe.

When the rover actively guides itself with its cameras, progress is safer, but much slower because of all the image processing needed. It may progress by as little as 10 meters an hour, which is about the distance from the goal line to the 10 yard line on an American football field. This method must be used whenever the rover doesn’t have a clear view of the route ahead, which is often the case due to rough and hilly terrain.

As of early 2015, the farthest Curiosity has driven in a single day is 144 meters. Opportunity’s longest daily drive was 224 meters, a distance the length of two American football fields.

If ground controllers could get a better view of the path ahead, they could devise instructions allowing a future rover to safely drive much further in a day.

That’s where the idea of a drone helicopter comes in. The helicopter could fly out ahead of the rover every day. Images made from its aerial vantage point would be invaluable to ground controllers for identifying points of scientific interest, and planning driving routes to get there.

Flying a helicopter on Mars poses special challenges. One advantage is that Martian gravity is only 38% as strong as that of Earth, so that the helicopter wouldn’t need to generate as much lift as one of the same mass on Earth. A helicopter’s propeller blades generate lift by pushing air downward. This is harder to do on Mars than on Earth, because the Martian atmosphere is on hundred times thinner. To displace enough air, the propeller blades would need to spin very quickly, or to be very large.

The copter must be capable of flying on its own, using prior instructions, maintaining stable flight along a pre-specified route. It must land and take off repeatedly in rocky Martian terrain. Finally it must be capable of surviving the harsh conditions of Mars, where the temperature plummets to 100 degrees Fahrenheit or lower every night.

The JPL engineers designed a copter with a mass of 1 kilogram; a tiny fraction of the 900 kg mass of the Curiosity rover. Its propeller blades span 1.1 meters from blade tip to blade tip, and are capable of spinning at 3400 rotations per minute. The body is about the size of a tissue box.

The copter is solar powered, with a disk of solar cells gathering enough power every day to power a flight of two to three minutes and to heat the vehicle at night. It can fly about half a kilometer in that time, gathering images for transmission to ground control as it goes. Engineers expect that the reconnaissance that the drone copter gathers will be invaluable in planning a rover’s drives, tripling the distance that can be traveled in a day.

References and further reading:
Thanks to Mark Maimone of NASA Jet Propulsion Laboratory for information about the daily driving distances of Curiosity and Opportunity.

J.J. Biesiadecki, P. C. Leger, and M.W. Maimone (2007), ‘tradeoffs between directed and autonomous driving on the Mars exploration rovers’, The International Journal of Robotics Research, 26(1), 91-104

E. Howell, Opportunity Mars rover treks past 41 kilometers towards ‘Marathon Valley’, Universe Today, Dec. 2014.

T. Reyes, An incredible journey, Mars Curiosity rover reaches base of Mount Sharp. Universe Today, Sept. 2014.

Helicopter could be ‘scout’ for Mars rovers. NASA Jet Propulsion Laboratory Press release. January 22, 2015.

Crazy Engineering: The Mars helicopter. NASA Jet Propulsion Laboratory video.

Curiosity- Mars Science Laboratory, NASA.

Mars- Future rover plans. NASA

Who Speaks for Earth? The Controversy over Interstellar Messaging

War of the Worlds

Should we beam messages into deep space, announcing our presence to any extraterrestrial civilizations that might be out there? Or, should we just listen? Since the beginnings of the modern Search for Extraterrestrial Intelligence (SETI), radio astronomers have, for the most part, followed the listening strategy.

In 1999, that consensus was shattered. Without consulting with other members of the community of scientists involved in SETI, a team of radio astronomers at the Evpatoria Radar Telescope in Crimea, led by Alexander Zaitsev, beamed an interstellar message called ‘Cosmic Call’ to four nearby sun-like stars. The project was funded by an American company called Team Encounter and used proceeds obtained by allowing members of the general public to submit text and images for the message in exchange for a fee.

Similar additional transmissions were made from Evpatoria in 2001, 2003, and 2008. In all, transmissions were sent towards twenty stars within less than 100 light years of the sun. The new strategy was called Messaging to Extraterrestrial Intelligence (METI). Although Zaitsev was not the first to transmit an interstellar message, he and his associates where the first to systematically broadcast to nearby stars. The 70 meter radar telescope at Evpatoria is the second largest radar telescope in the world.

In the wake of the Evpatoria transmissions a number of smaller former NASA tracking and research stations collected revenue by making METI transmissions as commercially funded publicity stunts. These included a transmission in the fictional Klingon language from Star Trek to promote the premier of an opera, a Dorito’s commercial, and the entirety of the 2008 remake of the classic science fiction movie “The Day the Earth Stood Still”. The specifications of these commercial signals have not been made public, but they were most likely much too faint to be detectable at interstellar distances with instruments comparable to those possessed by humans.

Zaitsev’s actions stirred divisive controversy among the community of scientists and scholars concerned with the field. The two sides of the debate faced off in a recent special issue of the Journal of the British Interplanetary Society, resulting from a live debate sponsored in 2010 by the Royal Society at Buckinghamshire, north of London, England.

Alexander L. Zaitsev- Chief scientist of the Russian Academy of Science’s Institute of Radio Engineering and Electronics, and head of the group that transmitted interstellar messages using the Evpatoria Planetary Radar telescope. (credit: Rumin)
Alexander L. Zaitsev- Chief scientist of the Russian Academy of Science’s Institute of Radio Engineering and Electronics, and head of the group that transmitted interstellar messages using the Evpatoria Planetary Radar telescope. (credit: Rumin)

Modern SETI got its start in 1959, when astrophysicists Giuseppe Cocconi and Phillip Morrison published a paper in the prestigious scientific journal Nature, in which they showed that the radio telescopes of the time were capable of receiving signals transmitted by similar counterparts at the distances of nearby stars. Just months later, radio astronomer Frank Drake turned an 85 foot radio telescope dish towards two nearby sun-like stars and conducted Project Ozma, the first SETI listening experiment. Morrison, Drake, and the young Carl Sagan supposed that extraterrestrial civilizations would “do the heavy lifting” of establishing powerful and expensive radio beacons announcing their presence. Humans, as cosmic newcomers that had just invented radio telescopes, should search and listen. There was no need to take the risk, however small, of revealing our presence to potentially hostile aliens.

Drake and Sagan did indulge in one seeming exception to their own moratorium. In 1974, the pair devised a brief 1679 bit message that was transmitted from the giant Arecibo Radar Telescope in Puerto Rico. But the transmission was not a serious attempt at interstellar messaging. By intent, it was aimed at a vastly distant star cluster 25,000 light years away. It merely served to demonstrate the new capabilities of the telescope at a rededication ceremony after a major upgrade.

In the 1980’s and 90’s SETI researchers and scholars sought to formulate a set of informal rules for the conduct of their research. The First SETI Protocol specified that any reply to a confirmed alien message must be preceded by international consultations, and an agreement on the content of the reply. It was silent on the issue of transmissions sent prior to the discovery of an extraterrestrial signal.

David Brin- Space scientist, futurist consultant, and science fiction writer (credit: Glogger)
David Brin- Space scientist, futurist consultant, and science fiction writer (credit: Glogger)
A Second SETI Protocol was to have addressed the issue, but, somewhere along the way, critics charge, something went wrong. David Brin, a space scientist, futurist consultant, and science fiction writer was a participant in the protocol discussion. He charged that “collegial discussion started falling apart” and “drastic alterations of earlier consensus agreements were rubber-stamped, with the blatant goal of removing all obstacles from the path of those pursuing METI”.

Brin accuses “the core community that clusters around the SETI Institute in Silicon Valley, California”, including astronomers Jill Tartar and Seth Shostak of “running interference for and enabling others around the world- such as Russian radio astronomer Dr. Alexander Zaitsev” to engage in METI efforts. Shostak denies this, and claims he simply sees no clear criteria for regulating such transmissions.

Brin, along with Michael A. G. Michaud, a former U.S. Foreign Service Officer and diplomat who chaired the committee that formulated the first and second protocol, and John Billingham, the former head of NASA’s short lived SETI effort, resigned their memberships in SETI related committees to protest the alterations to the second protocol.

The founders of SETI felt that extraterrestrial intelligence was likely to be benign. Carl Sagan speculated that extraterrestrial civilizations (ETCs) older than ours would, under the pressure of necessity, become peaceful and environmentally responsible, because those that didn’t would self-destruct. Extraterrestrials, they supposed, would engage in interstellar messaging because of a wish to share their knowledge and learn from others. They supposed that ETCs would establish powerful omnidirectional beacons in order to assist others in finding them and joining a communications network that might span the galaxy. Most SETI searches have been optimized for detecting such steady constantly transmitting beacons.

Over the fifty years since the beginnings of SETI, searches have been sporadic and plagued with constant funding problems. The space of possible directions, frequencies, and coding strategies has only barely been sampled so far. Still, David Brin contends that whole swaths of possibilities have been eliminated “including gaudy tutorial beacons that advanced ETCs would supposedly erect, blaring helpful insights to aid all newcomers along the rocky paths”. The absence of obvious, easily detectable evidence of extraterrestrial intelligence has led some to speak of the “Great Silence”. Something, Brin notes, “has kept the prevalence and visibility of ETCs below our threshold of observation”. If alien civilizations are being quiet, could it be that they know something that we don’t know about some danger?

Alexander Zaitsev thinks that such fears are unfounded, but that other civilizations might suffer from the same reluctance to transmit that he sees as plaguing humanity. Humanity, he thinks, should break the silence by beaming messages to its possible neighbors. He compares the current state of humanity to that of a man trapped in a one-man prison cell. “We”, he writes “do not want to live in a cocoon, in a ‘one –man cell’, without any rights to send a message outside, because such a life is not INTERESTING! Civilizations forced to hide and tremble because of farfetched fears are doomed to extinction”. He notes that in the ‘60’s astronomer Sebastian von Hoerner speculated that civilizations that don’t engage in interstellar communication eventually decline through “loss of interest”.

METI critics maintain that questions of whether or not to send powerful, targeted, narrowly beamed interstellar transmissions, and of what the content of those transmissions should be needs to be the subject of broad international and public discussion. Until such discussion has taken place, they want a temporary moratorium on such transmissions.

Seth Shostak- SETI Institute radio astronomer (credit: B D Engler)
Seth Shostak- SETI Institute radio astronomer (credit: B D Engler)
On the other hand, SETI Institute radio astronomer Seth Shostak thinks that such deliberations would be pointless. Signals already leak into space from radio and television broadcasting, and from civilian and military radar. Although these signals are too faint to be detected at interstellar distances with current human technology, Shostak contends that with the rapid growth in radio telescope technology, ETCs with technology even a few centuries in advance of ours could detect this radio leakage. Billingham and Benford counter that to collect enough energy to tune in on such leakage; an antenna with a surface area of more than 20,000 square kilometers would be needed. This is larger than the city of Chicago. If humans tried to construct such a telescope with current technology it would cost 60 trillion dollars.

Shostak argues that exotic possibilities might be available to a very technologically advanced society. If a telescope were placed at a distance of 550 times the Earth’s distance from the sun, it would be in a position to use the sun’s gravitational field as a gigantic lens. This would give it an effective collecting area vastly larger than the city of Chicago, for free. If advanced extraterrestrials made use of their star’s gravitational field in this way, Shostak maintains “that would give them the capacity to observe many varieties of terrestrial transmissions, and in the optical they would have adequate sensitivity to pick up the glow of street lamps”. Even Brin conceded that this idea was “intriguing”.

Civilizations in a position to do us potential harm through interstellar travel, Shostak contends, would necessarily be technologically advanced enough to have such capabilities. “We cannot pretend that our present level of activity with respect to broadcasting or radar usage is ‘safe’. If danger exists, we’re already vulnerable” he concludes. With no clear means to say what extraterrestrials can or can’t detect, Shostak feels the SETI community has nothing concrete to contribute to the regulation of radio transmissions.

Could extraterrestrials harm us? In 1897 H. G. Wells published his science fiction classic “The War of the Worlds” in which Earth was invaded by Martians fleeing their arid, dying world. Besides being scientifically plausible in terms of its times, Wells’ novel had a political message. An opponent of British colonialism, he wanted his countrymen to imagine what imperialism was like from the other side. Tales of alien invasion have been a staple of science fiction ever since. Some still regard European colonialism as a possible model for how extraterrestrials might treat humanity. The eminent physicist Steven Hawking thinks very advanced civilizations might have mastered interstellar travel. Hawking warned that “If aliens visit us, the outcome would be much as when Columbus landed in America, which didn’t turn out well for the Native Americans”.

Though dismissing Hawking’s fears of alien invasion as an “unlikely speculation”, David Brin notes that interstellar travel by small automated probes is quite feasible, and that such a probe could potentially do harm to us in many ways. It might, for example, steer an asteroid onto a collision course with Earth. A relatively small projectile traveling at one tenth the speed of light could wreak terrible damage by simply colliding with our planet. “The list of unlikely, but physically quite possible scenarios is very long” he warns.

Diplomat Michael Michaud warns that “We can all understand the frustration of not finding any signals after fifty years of intermittent searching” but “Impatience with the search is not a sufficient justification for introducing a new level of potential risk for our entire species”.

METI critics David Brin, James Benford, and James Billingham think that the current lack of results from SETI warrants a different sort of response than METI. They call for a reassessment of the search strategy. From the outset, SETI researchers have assumed that extraterrestrials will use steady beacons transmitting constantly in all directions to attract our attention. Recent studies of interstellar radio propagation and the economics of signaling show that such a beacon, which would need to operate on a vast timescale, is not an efficient way to signal.

Instead, an alien civilization might compile a list of potentially habitable worlds in its neighborhood and train a narrowly beamed signal on each member of the list in succession. Such brief “ping” messages might be repeated, in sequence, once a year, once a decade, or once a millennium. Benford and Billingham note that most SETI searches would miss this sort of signal.

The SETI Institute’s Allen telescope array, for example, is designed to target narrow patches of sky (such as the space around a sun-like star) and search those patches in sequence, for the presence of continuously transmitting beacons. It would miss a transient “ping” signal, because it would be unlikely to be looking in the right place at the right time. Ironically, the Evpatoria messages, transmitted for less than a day, are examples of such transient signals.

Benford and Billingham propose the construction of a new radio telescope array designed to constantly monitor the galactic plane (where stars are most abundant) for transient signals. Such a telescope array, they estimate, would cost about 12 million dollars, whereas a serious, sustained METI program would cost billions.

The METI controversy continues. On February 13, the two camps debated each other at the American Association for the Advancement of Science conference in San Jose, California. At that conference David Brin commented “It’s an area where opinion rules, and everyone has a fierce opinion”. In the wake of the meeting a group of 28 scientists, scholars, and business leaders issued a statement that “We feel the decision whether or not to transmit must be based on a worldwide consensus, and not a decision based on the wishes of a few individuals with access to powerful communications equipment”.

References and Further Reading:

J. Benford, J. Billingham, D. Brin, S. Dumas, M. Michaud, S. Shostak, A. Zaitsev, (2014) Messaging to Extraterrestrial Intelligence special section, Journal of the British Interplanetary Society, 67, p. 5-43.

The SETI Institute

D. Brin, Shouting at the cosmos: How SETI has taken a worrisome turn into dangerous territory.

F. Cain (2013) How could we find aliens? The search for extraterrestrial intelligence (SETI), Universe Today.

E. Hand (2015), Researchers call for interstellar messages to alien civilizations, Science Insider, Science Magazine.

P. Patton (2014) Communicating across the cosmos, Part 1: Shouting into the darkness, Part 2: Petabytes from the Stars, Part 3: Bridging the Vast Gulf, Part 4: Quest for a Rosetta Stone, Universe Today.