Technosignatures and the Search for Extraterrestrial Intelligence

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A rendering of a potential Dyson sphere, named after Freeman A. Dyson. As proposed by the physicist and astromomer decades ago, they would collect solar energy on a solar system wide scale for highly advanced civilizations. (SentientDevelopments.com)

The word “SETI” pretty much brings to mind the search for radio signals come from distant planets, the movie “Contact,” Jill Tarter, Frank Drake and perhaps the SETI Institute, where the effort lives and breathes.

But there was a time when SETI — the Search for Extraterrestrial Intelligence — was a significantly broader concept, that brought in other ways to look for intelligent life beyond Earth.

In the late 1950s and early 1960s — a time of great interest in UFOs, flying saucers and the like — scientists not only came up with the idea of searching for distant intelligent life via unnatural radio signals, but also by looking for signs of unexpectedly elevated heat signatures and for optical anomalies in the night sky.

The history of this search has seen many sharp turns, with radio SETI at one time embraced by NASA, subsequently de-funded because of congressional opposition, and then developed into a privately and philanthropically funded project of rigor and breadth at the SETI Institute.  The other modes of SETI went pretty much underground and SETI became synonymous with radio searches for ET life.

But this history may be about to take another sharp turn as some in Congress and NASA have become increasingly interested in what are now called “technosignatures,” potentially detectable signatures and signals of the presence of distant advanced civilizations.  Technosignatures are a subset of the larger and far more mature search for biosignatures — evidence of microbial or other primitive life that might exist on some of the billions of exoplanets we now know exist.

And as a sign of this renewed interest, a technosignatures conference was scheduled by NASA at the request of Congress (and especially retiring Republican Rep. Lamar Smith of Texas.)  The conference took place in Houston late last month, and it was most interesting in terms of the new and increasingly sophisticated ideas being explored by scientists involved with broad-based SETI.

“There has been no SETI conference this big and this good in a very long time,” said Jason Wright, an astrophysicist and professor at Pennsylvania State University and chair of the conference’s science organizing committee.  “We’re trying to rebuild the larger SETI community, and this was a good start.”

 

At this point, the search for technosignatures is often likened to that looking for a needle in a haystack. But what scientists are trying to do is define their haystack, determine its essential characteristics, and learn how to best explore it. (Wiki Commons)

 

During the three day meeting in Houston, scientists and interested private and philanthropic reps. heard talks that ranged from the trials and possibilities of traditional radio SETI to quasi philosophical discussions about what potentially detectable planetary transformations and by-products might be signs of an advanced civilization. (An agenda and videos of the talks are here.)

The subjects ranged from surveying the sky for potential millisecond infrared emissions from distant planets that could be purposeful signals, to how the presence of certain unnatural, pollutant chemicals in an exoplanet atmosphere that could be a sign of civilization.  From the search for thermal signatures coming from megacities or other by-products of technological activity, to the possible presence of “megastructures” built to collect a star’s energy by highly evolved beings.

Michael New is Deputy Associate Administrator for Research within NASA’s Science Mission Directorate. He was initially trained in chemical physics. (NASA)

All but the near infrared SETI are for the distant future — or perhaps are on the science fiction side — but astronomy and the search for distant life do tend to move forward slowly.  Theory and inference most often coming well before observation and detection.

So thinking about the basic questions about what scientists might be looking for, Wright said, is an essential part of the process.

Indeed, it is precisely what Michael New, Deputy Associate Administrator for Research within NASA’s Science Mission Directorate, told the conference. 

He said that he, NASA and Congress wanted the broad sweep of ideas and research out there regarding technosignatures, from the current state of the field to potential near-term findings, and known limitations and possibilities.

“The time is really ripe scientifically for revisiting the ideas of technosignatures and how to search for them,” he said.

He offered the promise of NASA help  (admittedly depending to some extent on what Congress and the administration decide) for research into new surveys, new technologies, data-mining algorithms, theories and modelling to advance the hunt for technosignatures.

 

Crew members aboard the International Space Station took this nighttime photograph of much of the Atlantic coast of the United States. The ability to detect the heat and light from this kind of activity on distant exoplanets does not exist today, but some day it might and could potentially help discover an advanced extraterrestrial civilization. (NASA)

 

Among the several dozen scientists who discussed potential signals to search for were the astronomer Jill Tarter, former director of the Center for SETI Research, Planetary Science Institute astrobiologist David Grinspoon and University of Rochester astrophysicist Adam Frank.  They all looked at the big picture, what artifacts in atmospheres, on surfaces and perhaps in space that advanced civilizations would likely produce by dint of their being “advanced.”

All spoke of the harvesting of energy to perform work as a defining feature of a technological planet, with that “work” describing transportation, construction, manufacturing and more.

Beings that have reached the high level of, in Frank’s words, exo-civilization produce heat, pollutants, changes to their planets and surroundings in the process of doing that work.  And so a detection of highly unusual atmospheric, thermal, surface and orbital conditions could be a signal.

One example mentioned by several speakers is the family of chemical chloroflourohydrocarbons (CFCs,)  which are used as commercial refrigerants, propellants and solvents.

Astronomner Jill Tarter is an iconic figure in the SETI world and led the SETI Institute for 30 years. (AFP)

These CFCs are a hazardous and unnatural pollutant on Earth because they destroy the ozone layer, and they could be doing something similar on an exoplanet.  And as described in the conference, the James Webb Space Telescope — once it’s launch and working — could most likely detect such an atmospheric compound if it’s in high concentration and the project was given sufficient telescope time.

A similar single finding described by Tarter that could be revolutionary is the radioactive isotope tritium, which is a by-product of the nuclear fusion process.  It has a short half-life and so any distant discovery would point to a recent use of nuclear energy (as long as it’s not associated with a recent supernova event, which can also produce tritium.)

But there many other less precise ideas put forward.

Glints on the surface of planets could be the product of technology,  as might be weather on an exoplanet that has been extremely well stabilized, modified planetary orbits and chemical disequilibriums in the atmosphere based on the by-products of life and work.  (These disequilibriums are a well-established feature of biosignature research, but Frank presented the idea of a technosphere which would process energy and create by-products at a greater level than its supporting biosphere.)

Another unlikely but most interesting example of a possible technosignature put forward by Tarter and Grinspoon involved the seven planets of the Trappist-1 solar system, all tidally locked and so lit on only one side.  She said that they could potentially be found to be remarkably similar in their basic structure, alignment and dynamics. As Tarter suggested, this could be a sign of highly advanced solar engineering.

 

Artist rendering of the imagined Trappist-1 solar system that had been terraformed to make the planets similar and habitable.  The system is one of the closest found to our own — about 40 light years.

 

Grinspoon seconded that notion about Trappist-1, but in a somewhat different context.

He has worked a great deal on the question of today’s anthroprocene era — when humans actively change the planet — and he expanded on his thinking about Earth into the galaxies.

Grinspoon said that he had just come back from Japan, where he had visited Hiroshima and its atomic bomb sites, and came away with doubts that we were the “intelligent” civilization we often describe ourselves in SETI terms.  A civilization that may well self destruct — a fate he sees as potentially common throughout the cosmos — might be considered “proto-intelligent,” but not smart enough to keep the civilization going over a long time.

Projecting that into the cosmos, Grinspoon argued that there may well be many such doomed civilizations, and then perhaps a far smaller number of those civilizations that make it through the biological-technological bottleneck that we seem to be facing in the centuries ahead.

These civilizations, which he calls semi-immortal, would develop inherently sustainable methods of continuing, including modifying major climate cycles, developing highly sophisticated radars and other tools for mitigating risks, terraforming nearby planets, and even finding ways to evolve the planet as its place in the habitable zone of its host star becomes threatened by the brightening or dulling of that star.

The trick to trying to find such truly evolved civilizations, he said, would be to look for technosignatures that reflect anomalous stability and not rampant growth. In the larger sense, these civilizations would have integrated themselves into the functioning of the planet, just as oxygen, first primitive and then complex life integrated themselves into the essential systems of Earth.

And returning to the technological civilizations that don’t survive, they could produce physical artifacts that now permeate the galaxy.

 

MeerKAT, originally the Karoo Array Telescope, is a radio telescope consisting of 64 antennas now being tested and verified in the Northern Cape of South Africa. When fully functional it will be the largest and most sensitive radio telescope in the southern hemisphere until the Square Kilometre Array is completed in approximately 2024. (South African Radio Astronomy Observatory)

 

This is exciting – the next phase Square kilometer Array (SKA2) will be able to detect Earth-level radio leakage from nearby stars. (South African Radio Astronomy Observatory)

 

While the conference focused on technosignature theory, models, and distant possibilities, news was also shared about two concrete developments involving research today.

The first involved the radio telescope array in South Africa now called MeerKAT,  a prototype of sorts that will eventually become the gigantic Square Kilometer Array.

Breakthrough Listen, the global initiative to seek signs of intelligent life in the universe, would soon announce the commencement of  a major new program with the MeerKAT telescope, in partnership with the South African Radio Astronomy Observatory (SARAO).

Breakthrough Listen’s MeerKAT survey will examine a million individual stars – 1,000 times the number of targets in any previous search – in the quietest part of the radio spectrum, monitoring for signs of extraterrestrial technology. With the addition of MeerKAT’s observations to its existing surveys, Listen will operate 24 hours a day, seven days a week, in parallel with other surveys.

This clearly has the possibility of greatly expanded the amount of SETI listening being done.  The SETI Institute, with its radio astronomy array in northern California and various partners, have been listening for almost 60 years, without detecting a signal from our galaxy.

That might seem like a disappointing intimation that nothing or nobody else is out there, but not if you listen to Tarter explain how much listening has actually been done.  Almost ten years ago, she calculated that if the Milky Way galaxy and everything in it was an ocean, then SETI would have listened to a cup full of water from that ocean.  Jason Wright and his students did an updated calculation recently, and now the radio listening amounts to a small swimming pool within that enormous ocean.

 

The NIROSETI team with their new infrared detector inside the dome at Lick Observatory. Left to right: Remington Stone, Dan Wertheimer, Jérome Maire, Shelley Wright, Patrick Dorval and Richard Treffers. (Laurie Hatch)

The other news came from Shelley Wright of the University of California, San Diego, who has been working on an optical SETI instrument for the Lick Observatory.

The Near-Infrared Optical SETI (NIROSETI) instrument she and her colleagues have developed is the first instrument of its kind designed to search for signals from extraterrestrials at near-Infrared wavelengths. The near-infrared regime is an excellenr spectral region to search for signals from extraterrestrials, since it offers a unique window for interstellar communication.

The NIROSETI instrument utilizes two near-infrared photodiodes to be able to detect artificial, very fast (nanosecond) pulses of infrared radiation.

The NIROSETI instrument, which is mounted on the Nickel telescope at Lick Observatory, splits the incoming near-infrared light onto two channels, and then checks for coincident events, which indicate signals that are identified by both detectors simultaneously.

Jason Wright is an assistant professor of astronomy and astrophysics at Penn State. His reading list is here.

Wright of Penn State was especially impressed by the project, which he said can look at much of the sky at once and was put together with on very limited budget.

Wright, who teaches a course on SETI at Penn State and is a co-author of a recent paper trying to formalize SETI terminology, said his own take-away from the conference is that it may well represent an important and positive moment in the history of technosignatures.

“Without NASA support, the whole field has lacked the normal structure by which astronomy advances,” he said.  “No teaching of the subject, no standard terms, no textbook to formalize findings and understandings.

“The Seti Institiute carried us through the dark times, and they did that outside of normal, formal structures. The Institute remains essential, but hopefully that reflex identification will start to change.”

 

Participants in the technosignatures conference in Houston last month, the largest SETI gathering in years.  And this one was sponsored by NASA and put together by the NExSS for Exoplanet Systems Science (NExSS,)  an interdisciplinary agency initiative. (Delia Enriquez)
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SETI Reconceived and Broadened; A Call for Community Proposals

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A screenshot from a time lapse video of radio telescopes by Harun Mehmedinovic and Gavin Heffernan of Sunchaser Pictures was shot at several different radio astronomy facilities—the Very Large Array (VLA) Observatory in New Mexico, Owens Valley Observatory in Owens Valley California, and Green Bank Observatory in West Virginia. All three of these facilities have been or are still being partly used by the SETI (Search for the Extraterrestrial Intelligence) program. You can watch the video at: https://www.youtube.com/watch?v=SrxpgUJoHRc
A screenshot from a time lapse video of radio telescopes by Harun Mehmedinovic and Gavin Heffernan of Sunchaser Pictures that was shot at several different radio astronomy facilities—the Very Large Array (VLA) Observatory in New Mexico, Owens Valley Observatory in Owens Valley California, and Green Bank Observatory in West Virginia. All three of these facilities have been or are still being partly used by the SETI (Search for the Extraterrestrial Intelligence) program.

Earlier this summer, Natalie Cabrol, the director of the Carl Sagan Center of the SETI Institute, described a new direction for her organization in Astrobiology Magazine, and I wrote a Many World column about the changes to come.

Cabrol’s Alien Mindscapes – Perspective on the Search for Extraterrestrial Intelligence” laid out a plan for the new approach to SETI that would take advantage of the goldmine of new exoplanet discoveries in the past decade, as well as the data from fast-advancing technologies.  These fresh angles and masses of information come, she wrote,  from the worlds of astronomy and astrophysics, as well as astrobiology and the biological, geological, environmental, cognitive, mathematical, social, and computational sciences.

In her article,  Cabrol said that a call would be coming for community input on how to develop of a Virtual Institute for SETI Research. Its primary goal, she said, would be to “understand how intelligent life interacts with its environment and communicates.”

That call for white papers has now gone out in a release from SETI, which laid out the questions the organization is looking to address:

Question 1: How abundant and diverse is intelligent life in the Universe?

The Virtual Institute will use data synergistically from astrobiology, biological sciences, space and planetary exploration, and geosciences to quantitatively characterize the potential abundance and diversity of intelligent life in the Universe. The spatiotemporal distribution of potential intelligent life will be considered using models of the physicochemical evolution of the Universe.

Question 2: How does intelligent life communicate?

By drawing from a combination of cognitive sciences, neuroscience, communication and information theory, mathematical sciences, bio-neural computing, data mining, and machine learning (among others), we will proactively explore and analyze communication in intelligent terrestrial species. Building upon these analyses, we will consider the physiochemical and biochemical models of newly discovered exoplanet environments to generate and map probabilistic neural and homolog systems, and infer the resulting range of viable alien sensing systems.

Question 3: How can we detect intelligent life?

Using the results (data and databases) of research conducted under Questions 1 and 2, we will consider the design and promising exploration strategies, instruments, exploration strategies, instruments, experimental protocols, technologies, and messaging (content and support) that may optimize the probabilities of detecting intelligent life beyond Earth.

And here is what SETI hopes interested scientists will do:

To support the goals and address the questions outlined above, we seek white papers that will serve as a foundation for the intellectual framework of the Virtual Institute’s roadmap – and that specifically describe: (a) scientific rationales (theories, hypotheses) as foundations for investigations; (b) concepts of experimental designs (methods, protocols, and metrics); (c) universal markers, signals, instruments, systems, technologies for communication; (d) target identification; and (e) ground- and space-based instrumentation, observing scenarios, instrument requirements, and exploration strategies.

To better understand the possible existence of intelligence and technology in the universe, and to learn how to detect it, we expect that proposals may draw from diverse scientific fields. These include astrobiology, astronomy/astrophysics, cognitive sciences, epistemology, geo- and environmental sciences, biosciences, mathematical sciences, social sciences, space sciences, communication theory, bioneural computing, machine learning, big data analytics, technology, instrument and software development, and other relevant fields.

White papers should be submitted in electronic form as PDF files to Dr. Nathalie Cabrol at ncabrol@seti.org. They should be no more than three pages in length, with a minimum 10-point font size. A figure can be included if of critical importance. It is anticipated that there will be an opportunity for interested respondents to present their contribution in person during a planned workshop in the summer of 2017.

Notification of opportunities to present will be made after the white paper deadline of February 17, 2017, and those most responsive to this call will be published in the Astrobiology Journal. Questions related to this call should be addressed to SETI Institute President and CEO Bill Diamond at bdiamond@seti.org

Here is the column I wrote when the Astrobiology Magazine paper came out in August:

Allen Telescope Array
SETI’s partially-built Allen Telescope Array in Northern California, the focus of the organization’s effort to collect signals from distant planets, and especially signals that just might have been created by intelligent beings.  (SETI)

For decades, the Search for Extraterrestrial Intelligence (SETI)  and its SETI Institute home base have been synonymous with the search for intelligent, technologically advanced life beyond Earth.  The pathway to some day finding that potentially sophisticated life has been radio astronomy and the parsing of any seemingly unnatural signals arriving from faraway star system — signals that just might be the product of intelligent extraterrestrial life.

It has been a lonely five decade search by now, with some tantalizing anomalies to decipher but no “eurekas.”  After Congress defunded SETI in the early 1990s — a Nevada senator led the charge against spending taxpayer money to look for “little green men” — the program has also been chronically in need of, and looking for, private supporters and benefactors.

But to those who know it better, the SETI Institute in Mountain View, California has long been more than that well-known listening program.  The Institute’s Carl Sagan Center for Research is home to scores of respected space, communication, and astrobiology scientists, and most have little or nothing to do with the specific message-analyzing arm of the organization.

And now, the new head of the Carl Sagan Center has proposed an ambitious effort to further re-define and re-position SETI and the Institute.  In a recent paper in the Astrobiology Journal, Nathalie Cabrol has proposed a much broader approach to the search for extraterrestrial intelligence, incorporating disciplines including psychology, social sciences, communication theory and even neuroscience to the traditional astronomical approach.

“To find ET, we must open our minds beyond a deeply-rooted, Earth-centric perspective, expand our research methods and deploy new tools,” she wrote. “Never before has so much data been available in so many scientific disciplines to help us grasp the role of probabilistic events in the development of extraterrestrial intelligence.

“These data tell us that each world is a unique planetary experiment. Advanced intelligent life is likely plentiful in the universe, but may be very different from us, based on what we now know of the coevolution of life and environment.”

The galaxay as viewed by the Hubble Space Telescope
With billions upon billions of galaxies, stars and exoplanets out there, some wonder if the absence of a SETI signal means none are populated by intelligent being.  Others say the search remains in its infancy, and needs new approaches.  The galaxy as viewed by the Hubble Space Telescope. (NASA/STScI)

She also wants to approach SETI with the highly interdisciplinary manner found in the burgeoning field of astrobiology — the search for signs of any kind of life beyond Earth. And in a nod to NASA’s Astrobiology Institute, which has funded most of her work, Cabrol went on to call for the establishment of a SETI Virtual Institute with participation from the global scientific community.

I had the opportunity recently to speak with Cabrol, who is a French-American astrobiologist with many years of research experience working with the NASA Mars rover program and with extremophile research as a senior SETI scientist.  She sees the SETI search for technologically advanced life as very much connected with the broader goals of the astrobiology field, which are focused generally on signs of potential microbial extraterrestrial life.  Yes, she said, SETI has thus far a distinctive and largely separate role in the overall astrobiology effort, but now she wants that role to be significantly updated and broadened.

“The time is right for a new chapter for us,” she said. “The origins of SETI were visionary — using the hot technology of the day {radio astronomy} to listen for signals.  But we don’t exactly know what to look and listen for.  We don’t know the ways that ET might interact with its own environment, and that’s a drawback when looking for potential communications we might detect.”

Cabrol foresees future SETI Institute research into neural systems and how they interact with the environment (“bioneural computing,”) much more on the theory and mechanisms of communication, as well as on big data analysis and machine learning.  And, of course, into how potential biosignatures might be detected on distant planets.

The ultimate goal, however, remains the same:  detecting intelligent life (if it’s out there.)

Nathalie Cabrol, director of SETI's Carl Sagan Institute, wants to expand and update SETI's approach to searching for intelligent life beyond our solar system. (NASA)
Nathalie Cabrol, director of SETI’s Carl Sagan Center, wants to expand and update SETI’s approach to searching for intelligent life beyond our solar system. (NASA)

But with so much progress in the sciences that could help improve the chances of finding evolved extraterrestrial life, she said, it’s time for SETI to focus on them as a way to expand the SETI vision and its strategies.

“The purpose is to expand the vision and strategies for SETI research and to break through the constraints imposed by imagining ET to be similar to ourselves,” she wrote. The new approach will “probe the alien landscapes and mindscapes, and generally further understanding of life in the universe.”

The Institute will soon put out a call for white papers on how to expand the SETI search beyond radio astronomy, with an emphasis on “life as we don’t know it.”  After getting those white papers — hopefully from scientists ranging from astronomers to evolutionary biologists — the Sagan Center  plans a workshop to create a roadmap.

Cabrol was emphatic in saying that the SETI search is not turning away from the original vision of its founders — especially astrophysicists Frank Drake, Jill Tarter and Carl Sagan — who were looking for a way to quantify the likelihood of intelligent and technologically-proficient life on distant planets.  Rather, it’s an effort to return to and update the initial SETI formulation, especially as expressed in the famed Drake Equation.

Drake Equation
The Drake Equatio,, as first presented in 1961 to a gathering of scientists at the National Radio Astronomy Observatory in Green Bank, W. Va.

“What Frank proposed was actually a roadmap itself,” Cabrol said.  “The equation takes into account how suitable stars are formed, how many planets they might have, how many might be Earth-like planets, and how many are habitable or inhabited.”

Drake’s equation was formulated for the pioneering Green Bank Conference more than 50 years ago, when basically none of the components of his formula had a number or range that could be associated with it.  That has changed for many of those components, but the answer to the original question — Are We Alone? — remains little closer to being answered.

“I’ve talked a great deal with my colleagues about what type of life can be out there,” she said.  “How different from Earth can it be?”

“Now we’re looking for habitable environments with life as we know it. But it’s time to add life as we don”t know it, too.  And that can help augment our targeting, help pinpoint better what we’re looking for.”

“We think one of the key issues is how ET communicates with its environment, and the great advances in neuroscience can help inform what we do.  The same with evolutionary biology.  Given an environment with life, we want to know, what kind of evolution might be anticipated.”

Connectivity network between disciplines showing the bridges and research avenues that link together space, planetary, and life sciences, geosciences, astrobiology, and cognitive and mathematical sciences. This representation is an expanded version of the Drake equation. It integrates all the historical factors now broken down in measurable terms and expanded to include the search for life we do not know using universal markers, and the disciplines, fields, and methods that will allow us to quantify them.
A diagram of the proposed SETI  “connectivity network” between disciplines showing the bridges and research avenues that link together space, planetary, and life sciences, geosciences, astrobiology, and cognitive and mathematical sciences. Cabrol describes it as  an expanded version of the Drake equation.  (Astrobiology Journal/SETI Institute.)

These are, of course, very long-term goals.  No extraterrestrial life has been detected, and researchers are just now beginning to debate and formulate what might constitute a biosignature on a faraway exoplanet or, what has more recently been coined, a “bio-hint.”

In her paper, Cabrol is also frank about the entirely practical, real-world reasons what SETI needs to change.

“Decades of perspective on both astrobiology and the Search for Extraterrestrial Intelligence (SETI) show how the former has blossomed into a dynamic and self-regenerating field that continues to create new research areas with time, whereas funding struggles  have left the latter starved of young researchers and in search of both a long-term vision and a development program.

“A more foundational reason may be that, from the outset, SETI is an all-or-nothing venture where finding a signal would be a world-changing discovery, while astrobiology is associated with related fields of inquiry in which incremental progress is always being made.”

Whatever changes arrive at the SETI Institute, it will continue with its trademark efforts — most importantly operating the Allen Telescope Array in Northern California and collaborations with numerous other SETI groups.  The array began its work in 2007 with 42 interconnected small radio telescopes, and  continues its constant search for incoming signals.  The SETI Institute had hoped to build the array up to 350 telescopes, but the funding has not been forthcoming.

Cabrol is clearly a scientific adventurer and risk taker.  During her extremophile research in Chile, she went scuba diving and free diving — that is, diving without scuba equipment — in the Licancabur Lake, some 20,000 feet above sea level.  It is believed to be an unofficial altitude record high-altitude for both kinds of diving.

With this kind of view of life, she is a logical candidate to bring substantial change to SETI.  The new primary questions for SETI and the institute to probe are: How abundant is intelligent life in the universe?  How does it communicate? How can we detect intelligent life?

As she concluded in her Astrobiology Journal article:

‘Ultimately, SETI’s vision should no longer be constrained by whether ET has technology, resembles us, or thinks like us. The approach presented here will make these attributes less relevant, which will vastly expand the potential sampling pool and search methods, ultimately increasing the odds of detection.

“Advanced, intelligent life beyond Earth is most likely plentiful, but we have not yet opened ourselves to the full potential of its diversity.”

 

 

 

 

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