Breakthrough Starshot is Now Looking for the Companies to Build its Laser-Powered Solar Sails to Other Stars

In 2015, Russian billionaire Yuri Milner established Breakthrough Initiatives, a non-profit organization dedicated to enhancing the search for extraterrestrial intelligence (SETI). In April of the following year, he and the organization be founded announced the creation of Breakthrough Starshot, a program to create a lightsail-driven “wafercraft” that would make the journey to the nearest star system – Proxima Centauri – within our lifetime.

In the latest development, on Wednesday May 23rd, Breakthrough Starshot held an “industry day” to outline their plans for developing the Starshot laser sail. During this event, the Starshot committee submitted a Request For Proposals (RFP) to potential bidders, outlining their specifications for the sail that will carry the wafercraft as it makes the journey to Proxima Centauri within our lifetimes.

As we have noted in several previous articles, Breakthrough Starshot calls for the creation of a gram-scale nanocraft being towed by a laser sail. This sail will be accelerated by an Earth-based laser array to a velocity of about 60,000 km/s (37,282 mps) – or 20% the speed of light (o.2 c). This concept builds upon the idea of a solar sail, a spacecraft that relies on solar wind to push itself through space.

An artist’s illustration of a light-sail powered by a radio beam (red) generated on the surface of a planet. Credit: M. Weiss/CfA

At this speed, the nanocraft would be able to reach the closest star system to our own – Proxima Centauri, located 4.246 light-years away – in just 20 years time. Since its inception, the team behind Breakthrough Starshot has invested considerable time and energy addressing the conceptual and engineering challenges such a mission would entail. And with this latest briefing, they are now looking to move the project from concept to reality.

In addition to being the Frank B. Baird, Jr. Professor of Science at Harvard University, Abraham Loeb is also the Chair of the Breakthrough Starshot Advisory Committee. As he explained to Universe Today via email:

“Starshot is an initiative to send a probe to the nearest star system at a fifth of the speed of light so that it will get there within a human lifetime of a couple of decades. The goal is to obtain photos of exo-planets like Proxima b, which is in the habitable zone of the nearest star Proxima Centauri, four light years away. The technology adopted for fulfilling this challenge uses a powerful (100 Giga-watt) laser beam pushing on a lightweight (1 gram) sail to which a lightweight electronics chip is attached (with a camera, navigation and communication devices). The related technology development is currently funded at $100M by Yuri Milner through the Breakthrough Foundation.”

In addition to outlining BI’s many efforts to find ETI – which include Breakthrough Listen, Breakthrough Message and Breakthrough Watch – the RFP focused on Starshot’s Objectives. As was stated in the RFP:

“The scope of this RFP addresses the Technology Development phase – to explore LightSail concepts, materials, fabrication and measurement methods, with accompanying analysis and simulation that creates advances toward a viable path to a scalable and ultimately deployable LightSail.”

A phased laser array, perhaps in the high desert of Chile, propels sails on their journey. Credit: Breakthrough Initiatives

As Loeb indicated, this RFP comes not long after another “industry day” that was related to the development of the technology of the laser – termed the “Photon Engine”. In contrast, this particular RFP was dedicated to the design of the laser sail itself, which will carry the nanocraft to Proxima Centauri.

“The Industry Day was intended to inform potential partners about the project and request for proposals (RFP) associated with research on the sail materials and design,” added Loeb. “Within the next few years we hope to demonstrate the feasibility of the required sail and laser technologies. The project will allocate funds to experimental teams who will conduct the related research and development work. ”

The RFP also addressed Starshot’s long-term goals and its schedule for research and development in the coming years. These include the investment in $100 million over the next five years to determine the feasibility of the laser and sail, to invest the value of the European Extremely Large Telescope (EELT) from year 6 to year 11 and build a low-power prototype for space testing, and invest the value of the Large Hardon Collider (LHC) over a 20 year period to develop the final spacecraft.

“The European Extremely Large Telescope (EELT) will cost on order of a billion [dollars] and the Large Hadron Collider cost was ten times higher,’ said Loeb. “These projects were mentioned to calibrate the scale of the cost for the future phases in the Starshot project, where the second phase will involve producing a demo system and the final step will involve the complete launch system.”

Artist’s impression of Proxima b, which was discovered using the Radial Velocity method. Credit: ESO/M. Kornmesser

The research and development schedule for the sail was also outlined, with three major phases identified over the next 5 years. Phase 1 (which was the subject of the RFP) would entail the development of concepts, models and subscale testing. Phase 2 would involve hardware validation in a laboratory setting, while Phase 3 would consist of field demonstrations.

With this latest “industry day” complete, Starshot is now open for submissions from industry partners looking to help them realize their vision. Step A proposals, which are to consist of a five-page summary, are due on June 22nd and will be assessed by Harry Atwater (the Chair of the Sail Subcommittee) as well as Kevin Parkin (head of Parkin Research), Jim Benford (muWave Sciences) and Pete Klupar (the Project Manager).

Step B proposals, which are to consist of a more detailed, fifteen-page summary, will be due on July 10th. From these, the finalists will be selected by Pete Worden, the Executive Director of Breakthrough Starshot. If all goes according to plan, the initiative hopes to launch the first lasersail-driven nanocraft in to Proxima Centauri in 30 years and see it arrive there in 50 years.

So if you’re an aerospace engineer, or someone who happens to run a private aerospace firm, be sure to get your proposals ready! To learn more about Starshot, the engineering challenges they are addressing, and their research, follow the links provided to the BI page. To see the slides and charts from the RFP, check out Starshot’s Solicitations page.

Further Reading: Centauri Dreams, Breakthrough Starshot

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

The WOW Signal Probably Didn’t Come from Aliens, or Comets as You Recently Heard

On August 15th, 1977, astronomers using the Big Ear radio telescope at Ohio State University detected a 72-second radio signal coming from space. This powerful signal, which quickly earned the nickname the “Wow! signal”, appeared to be coming from the direction of the Sagittarius Constellation, and some went so far as to suggest that it might be extra-terrestrial in origin.

Since then, the Wow! signal has been an ongoing source of controversy among SETI researchers and astronomers. While some have maintained that it is evidence of extra-terrestrial intelligence (ETI), others have sought to find a natural explanation for it. And thanks a team of researchers from the Center of Planetary Science (CPS), a natural explanation may finally have been found.

In the past, possible explanations have ranged from asteroids and exoplanets to stars and even signals from Earth – but these have all been ruled out. And then in 2016, the Center for Planetary Science – a Florida-based non-profit scientific and astronomical organization – proposed a hypothesis arguing that a comet and/or its hydrogen cloud could be the cause.

This was based on the fact that the Wow! signal was transmitting at a frequency of 1,420 MHz, which happens to be the same frequency as hydrogen. This explanation was also appealing because the movement of the comet served as a possible explanation for why the signal has not been detected since. To validate this hypothesis, the CPS team reportedly conducted 200 observations using a 10-meter radio telescope.

This telescope, they claim, was equipped with a spectrometer and a custom feed horn designed to collect a radio signal centered at 1420.25 MHz. Between Nov. 27th, 2016, and Feb. 24th, 2017, they monitored the area of space where the Wow! signal was detected, and found that a pair of Solar comets (which had not been discovered in 1977) happened to conform to their observations, and could therefore have been the source.

Spectra obtained from these comets – P/2008 Y2(Gibbs) and 266/P Christensen – indicated that they were emitting a radio frequency that was consistent with the Wow! signal. As Antonio Paris (a professor at the CPS), described in a recent paper that appeared in the Journal of the Washington Academy of Sciences:

“The investigation discovered that comet 266/P Christensen emitted a radio signal at 1420.25 MHz. All radio emissions detected were within 1° (60 arcminutes) of the known celestial coordinates of the comet as it transited the neighborhood of the ‘Wow!’ Signal. During observations of the comet, a series of experiments determined that known celestial sources at 1420 MHz (i.e., pulsars and/or active galactic nuclei) were not within 15° of comet 266/P Christensen.”

The Wow! signal represented as “6EQUJ5”. Credit: Big Ear Radio Observatory/NAAPO

The team also examined three other comets to see if they emitted similar radio signals. These comets – P/2013 EW90 (Tenagra), P/2016 J1-A (PANSTARRS), and 237P/LINEAR – were selected randomly from the JPL Small Bodies database, and were confirmed to emit a radio signal at 1420 MHz. Therefore, the results of this investigation conclude that the 1977 “Wow!” Signal was a natural phenomenon from a Solar System body.

However, not everyone is convinced. In response to the paper, Yvette Cendes – a PhD student with the Dunlap Institute at the University of Toronto – wrote a lengthy response on reddit as to why it fails to properly address the Wow! signal. For starters, she cites how the research team measured the signal strength in terms of decibels:

“I have never, ever, EVER used dB in a paper, nor have I ever read a paper in radio astronomy that measured signal strength in dB (except perhaps in the context of an instrumentation paper describing the systems of a radio telescope, i.e. not science but engineering.) We use a different unit in astronomy for flux density, the Jansky (Jy), where 1 Jy= ?230 dBm/(m2·Hz). (dB is a log scale, and Janskys are not.)”

Another point of criticism is the lack of detail in the paper, which would make reproducing the results very difficult – a central requirement where scientific research is concerned. Specifically, they do not indicate where the 10-meter radio telescope they used came from – i.e. which observatory of facility it belonged to, or even if it belonged to one at all – and are rather vague about its technical specification.

Spectra obtained from an area in the direction of the Sagittarius constellation. Credit: The Center for Planetary Science

Last, but not least, there is the matter of the environment in which the observations took place, which are not specified. This is also very important for radio astronomy, as it raised the issue of interference. As Cendes put it:

“This might sound pedantic, but this is insanely important in radio astronomy, where most signals we ever search for are a tiny fraction of the man-made ones, which can be millions of times brighter than an astronomical signal. (A cell phone on the moon would be one of the brighter radio astronomy sources in the sky, to give you an idea!) Radio Frequency Interference (RFI) is super important for the field, so much that people can spend their careers on it (I’ve written a chapter on my thesis on this myself), and the “radio environment” of an observatory can be worth a paper in itself.”

Beyond these apparent incongruities, Cendes also states that the hypothesis for the experiment was flawed. Essentially, the Big Ear searched for the same signal for a period of 22 years, but found nothing. If the comet hypothesis held true, there should be an explanation as to why no trace of the signal was found until this time. Alas, one is lacking, as far as this most recent study is concerned.

“And now you likely have an idea on why one-off events are so hard to prove in science,” she claims. “But then, this is really the major reason the Wow! signal is unsolved to this day- without a plausible explanation, [without] additional data, we just will never know.”

Though it may be hard to accept, it is entirely possible that we may never know what the Wow! signal truly was – whether it was a one-off event, a naturally-occurring phenomena, or something else entirely. And if the comet hypothesis should prove to be unverifiable, then that is certainly good news for the SETI enthusiasts!

While the elimination of natural explanations doesn’t prove that things like Wow! signal are proof of alien civilizations, it at least indicates that this possibility cannot be ruled out just yet. And for those hopeful that evidence of intelligent life will be someday found, that’s really the best we can hope for… for now!

Further Reading: Journal of the Washington Academy of Sciences, Astronomer Here!

Did We Arrive Early To The Universe’s Life Party?

The Fermi Paradox essentially states that given the age of the Universe, and the sheer number of stars in it, there really ought to be evidence of intelligent life out there. This argument is based in part on the fact that there is a large gap between the age of the Universe (13.8 billion years) and the age of our Solar System (4.5 billion years ago). Surely, in that intervening 9.3 billion years, life has had plenty of time to evolve in other star system!

However, new theoretical work performed by researchers from the Harvard-Smithsonian Center for Astrophysics (CfA) offers a different take on Fermi’s Paradox. According to their study, which will appear soon in the Journal of Cosmology and Astrophysics, they argue that life as we know it may have been a bit premature to the whole “intelligence party”, at least from a cosmological perspective.

For the sake of their study, titled “Relative Likelihood for Life as a Function of Cosmic Time“, the team calculated the likelihood of Earth-like planets forming within our Universe, starting from when the first stars formed (30 million years after the Big Bang) and continuing into the distant future. What they found was, barring any unforeseen restrictions, life as we know is determined by the mass of a star.

The Very Large Telescoping Interferometer firing it's adaptive optics laser. Credit: ESO/G. Hüdepohl
The Very Large Telescoping Interferometer firing it’s adaptive optics laser. Credit: ESO/G. Hüdepohl

As Avi Loeb – a scientist with the Harvard-Smithsonian Center for Astrophysics and the lead author on the paper – explained in a CfA press release:

“If you ask, ‘When is life most likely to emerge?’ you might naively say, ‘Now’. But we find that the chance of life grows much higher in the distant future. So then you may ask, why aren’t we living in the future next to a low-mass star? One possibility is we’re premature. Another possibility is that the environment around a low-mass star is hazardous to life.”

Essentially, higher-mass stars – i.e. those that have three or more times the mass of our Sun – have a shorter life-span, which means that they will likely die before life has a chance to form on a planet orbiting them. Lower mass stars, which are a class of red dwarfs that have 0.1 Solar masses, have much longer lifespans, with some astrophysical models indicating that they may stay in their main sequence phase for six to twelve trillion years.

In other words, the probability of life existing in our Universe grows over time. For the sake of their study, Loeb and his colleagues concluded that certain red dwarfs that are in their main sequence today could likely live for another 10 trillion years. By this time, the probability that life will have developed on some of their planets increased by a factor of 1000 over what it is today.

Hence, we could say that life as we know it – i.e. carbon-based organisms that evolved on Earth over the course of billions of years – emerged early in terms of cosmic history, rather than late. This might explain why it is that we haven’t found any evidence of intelligent life yet – maybe it just hasn’t had enough time to emerge. It’s certainly a better prospect than the possibility that they were killed off during the early phases of their star’s evolution (as other researchers have suggested).

NASA's James Webb Space Telescope, scheduled for launch in 2018, will be capable of measuring the spectrum of the atmospheres of Earthlike exoplanets orbiting small stars. Credit: NASA, Northrop Grumman
NASA’s James Webb Space Telescope, scheduled for launch in 2018, will be capable of measuring the spectrum of the atmospheres of Earthlike exoplanets orbiting small stars.
Credit: NASA/Northrop Grumman

However, as Dr. Loeb explained, the team also determined that there was an alternative to this hypothesis, which has to do with the particular risks faced by plants that form around low-mass stars. For instance, low-mass stars emit strong flares of UV radiation in their early life, which could adversely effect any planet orbiting it by stripping away its atmosphere.

So, in addition to life being premature on Earth, its possible that life on other planets is being wiped out before they have a chance to reach maturity. Ultimately, the only way to know for sure which possibility is correct is to continue hunting for Earth-like exoplanets and conducting spectroscopic searches of their atmospheres for biosignatures.

In this respect, missions like the Transiting Exoplanet Survey Satellite (TESS) and the James Webb Space Telescope will have their work cut out for them! Loeb also published a similar study titled “On the Habitability of Our Universe” as a preface for an upcoming book on the subject.

The Harvard-Smithsonian Center for Astrophysics, located in Cambridge, Massachusetts, is a joint collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. It’s scientists are dedicating to studying the origin, evolution and future of the universe.

Further Reading: CFA, arXiv

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.

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.

Communicating Across the Cosmos, Part 1: Shouting into the Darkness

Over the last 20 years, astronomers have discovered several thousand planets orbiting other stars. We now know that potentially habitable Earth-like planets are abundant in the cosmos. Such findings lend a new plausibility to the idea that intelligent life might exist on other worlds. Suppose that SETI (Search for Extraterrestrial Intelligence) researchers succeed in their quest to find a message from a distant exoplanet. How much information can we hope to receive or send? Can we hope to decipher its meaning? Can humans compose interstellar messages that are comprehensible to alien minds?

Such concerns were the topic of a two day academic conference on interstellar messages held at the SETI Institute in Mountain View, California; ‘Communicating across the Cosmos’. The conference drew 17 speakers from a wide variety of disciplines, including linguistics, anthropology, archeology, mathematics, cognitive science, philosophy, radio astronomy, and art. This article is the first of a series of installments about the conference. Today, we’ll explore the ways in which our society is already sending messages to extraterrestrial civilizations, both accidentally and on purpose.

Sending radio messages over sizable interstellar distances is feasible with present day technology. According to SETI Institute radio astronomer Seth Shostak, who presented at the conference, we are already — by accident — constantly signaling our presence to any extraterrestrial astronomers that might exist in our neighborhood of the galaxy. Some radio signals intended for domestic uses leak into space. The most powerful come from radars used for military purposes, air traffic control, and weather forecasting. Because these radars sweep across broad swaths of the sky, their signals travel out into space in many directions.

With radio telescopes no more sensitive than those astronomers on Earth use today, extraterrestrials out to distances of tens of light years could detect them and figure out that they were artificial. The Arecibo radar telescope in Puerto Rico is designed specifically to send a narrow beam of radio waves into space, usually to bounce them off celestial bodies and learn about their surfaces. For a receiver within its beam, it could be detected hundreds of light-years away.

FM radio and television broadcasts also leak out into space, but they are weaker and couldn’t be detected more than about one tenth of a light year away with present day human technology. This is quite a bit less than the distance to the nearest star. The size and sensitivity of radio telescopes is progressing rapidly. An alien civilization just a few centuries more advanced than us in radio technology could detect even these weak signals over vast distances in the galaxy. As our signals spread outward at the speed of light, they will reach progressively larger numbers of stars and planets, any one of which might be home to ETI. If they really are out there, they are likely to find us eventually.

Humans have been fascinated with formulating messages for extraterrestrials for a surprisingly long time. Eighteenth and nineteenth century scientists drew up proposals to make huge fire pits or plantings in the shapes of geometric figures that they hoped would be visible in the telescopes of the inhabitants of neighboring worlds. In the early days of radio, attempts were made to contact Mars and Venus.

As prospects for intelligent life within the solar system dimmed, attention turned to the stars. In the early 1970’s the first two spacecraft to escape the sun’s gravitational pull, Pioneer 10 and 11, each carried an engraved plaque designed to tell aliens where Earth is, and what human beings look like. Voyager 1 and 2 carried a more ambitious message of images and sounds encoded on a phonograph record. Both the Pioneer plaques and the Voyager records were devised by teams led by astronomers Carl Sagan and Frank Drake, both SETI pioneers. In 1974, the powerful Arecibo radio telescope beamed a brief 3 minute message towards a star cluster 21,000 light years away as part of a dedication ceremony for a major upgrade. The binary coded message was an image, including a stick figure of a human, our solar system, and some chemicals important to earthly life. The distant target was chosen simply because it was overhead at the time of the ceremony.

The plaque affixed to the Pioneer 10 and 11 spacecraft, the first spacecraft to leave our solar system. In the upper left corner is a diagram depicting the hydrogen atom, the most abundant element in the universe. The diagram symbolizes the transition of the electron from a spin-up to a spin-down state. This transition is responsible for radio emissions at the wavelength of 21 cm by clouds of hydrogen in interstellar space. This phenomenon is familiar to radio astronomers and provides a distance standard for indicating the size of the humans.  In the middle left is a representation of position of the sun with respect to the center of the galaxy and 14 pulsars.  At the bottom is a map of the solar system indicating the origin of the spacecraft at the sun's third planet.  The planets relative distances from the sun are given as binary numbers with the unit being one tenth of Mercury's distance from the sun.  At the right is a depiction of a human couple with the man's arm raised in gesture of friendly greeting and the pioneer spacecraft drawn in outline as a backdrop.
The plaque affixed to the Pioneer 10 and 11 spacecraft, the first spacecraft to leave our solar system. In the upper left corner is a diagram depicting the hydrogen atom, the most abundant element in the universe. The diagram symbolizes the transition of the electron from a spin-up to a spin-down state. This transition is responsible for radio emissions at the wavelength of 21 cm by clouds of hydrogen gas in interstellar space. This phenomenon is very familiar to radio astronomers and provides a distance standard used to indicate the sizes of the human beings. In the middle left is a representation of position of the sun with respect to the center of the galaxy and 14 pulsars. At the bottom is a map of the solar system indicating the origin of the spacecraft as the sun’s third planet. The relative distances of the planets from the sun are indicated as binary numbers with a unit one tenth the distance of Mercury from the sun. At the right is a depiction of a human couple with the man’s arm raised in a gesture of friendly greeting and the pioneer spacecraft drawn in outline as a backdrop NASA Ames Research Center.

Cultural anthropologist and conference speaker Klara Anna Capova said that in recent years, messaging to extraterrestrials has moved beyond science and become a commercial enterprise. In 1999 and 2003, a private company solicited content from the general public and transmitted these ‘Cosmic Call’ messages to several nearby sun-like stars from the 70 meter radio telescope of the Evpatoria Deep Space Center in Crimea, Ukraine.

In 2009, another private company transmitted 25,000 messages, collected via a website, towards the red dwarf star Gliese 581, 20 light years away. In 2008, a Dorito’s commercial was beamed to a sun-like star 42 light years away, and in 2009 Penguin books transmitted 1000 messages as part of a book promotion. In 2010, a greeting, spoken in the fictional Klingon language, was beamed towards the star Arcturus, 37 light years away. The message was sent to promote the opening of what was billed as the first authentic Klingon opera on Earth. As one conference speaker noted, there are no regulations on the transmission or content of such messages.

Actively messaging extraterrestrials is a controversial practice, and the director of the Evpatoria Center, Alexander Zaitsev, has faced criticism from some members of the scientific community for his actions. Traditionally, SETI researchers have simply listened for alien messages. A received message might allow humans to learn something about the nature and motives of its extraterrestrial senders. That might give us a basis for deciding whether or not it was wise and prudent to reply.

Drake’s Arecibo message, by intent, was beamed at a star cluster tens of thousands of light years away and was meant simply to demonstrate the capacity for interstellar messaging. The Pioneer and Voyager spacecraft likewise will not reach the stars for tens of thousands of years. On the other hand, the recent transmissions were directed at nearby stars, from which we might receive a reply in less than a century. At the conference, Seth Shostak advanced what he confessed was a provocative position. He said we shouldn’t worry too much about the recent transmissions, because the much weaker signals that constantly emanate from Earth would be detectable by extraterrestrial civilizations with more advanced radio technology anyway. “That horse”, he said “has already left the barn”.

In the next installment, we will explore the SETI Institute’s current and planned efforts to conduct our human search for extraterrestrial signals. We will consider the limits of our own signaling capacity, and learn that the amount of information we could send the aliens is truly vast.

References and Further Reading:

Communicating across the Cosmos: How can we make ourselves understood by other civilizations in the galaxy (2014), SETI Institute Conference Website

N. Atkinson (2008), Message from Earth beamed to alien world, Universe Today.

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

M. J. Crowe (1986) The Extraterrestrial Life Debate 1750-1900: The Idea of a Plurality of Worlds From Kant to Lowell, University of Cambridge, Cambridge, UK.

C. Sagan, F. Drake, A. Druyan, T. Ferris, J. Lomberg, L. S. Sagan (1978), Murmurs of Earth: The Voyager Interstellar Record, Random House, New York, NY.

W. T. Sullivan III; S. Brown, and C. Wetherill, (1978) Eavesdropping: The radio signature of Earth, Science 199(4327): 377-388.