Adam Frank is an astrophysicist at the University of Rochester and the author of Light of the Stars: Alien Worlds and the Fate of the Earth.
Prosthetic foreheads, that’s the problem. When thinking about life and intelligence in the universe, decades of bad sci-fi television have left us all with a case of the giggles, as we equate the word alien with actors bearing spikes or antennae. From little green men in flying saucers, with their triangular heads, to Klingons and their eyebrow ridges, we’ve learned as a culture to associate aliens with crazy conspiracy theories or deep nerdology.
It’s time to move past those associations because they’re beside the point now. From the newest science of other planets to our own experience with climate change on this one, our thinking about life, civilizations and the universe is in the midst of a profound transformation. Culturally and scientifically, we’re no longer giggling about alien life.
There’s a new interest in extraterrestrial civilizations and planets, wherever they might be found, and it’s driven by a remarkable new reality: Our power as a species has become nothing less than astonishing. Humanity has become a truly global technological civilization. There are literally half a million of us flying through the air in jet planes at any moment. Most of us carry computers in our pockets that give us instant access to a seemingly infinite trove of information and let us exist remotely, anywhere on the planet. We’ve flung thousands of machines into orbit. Our robots now wander the plains of Mars and orbit the skies of Jupiter. If all goes well, our grandchildren are just as likely to vacation in space as we holiday in Europe.
And in that way, we are building what we so long imagined was possible for powerful futuristic civilizations. Spaceships, talking computers, buildings stretching to the sky: We are becoming the aliens we’ve always dreamed about.
And then there are all the alien news stories stoking our fascination. Last month, Canadian astronomers detailed how their telescopes had captured a mysterious squeal of energy called a fast radio burst from across the cosmos. Unlike most astronomy stories, this one made global headlines in part because it included the possibility of aliens. And about a year ago, astronomers detected an object diving across the solar system that must have come from another star system. It was the first such visitor humans had ever seen. Once again headlines blared, asking if the object, named Oumuamua (Hawaiian for “infinite heaven”), was just an asteroid or perhaps an artifact of a distant intelligence. And, just a year or so before Oumuamua appeared, astronomers discovered the strange blinking behaviour of the so-called “WTF star,” which quickly introduced the term “alien megastructures” into the media’s lexicon.
In light of all these stories, you’d be justified asking if science is making progress in answering the ancient question of humanity’s cosmic uniqueness – or if it’s all just hype. But to answer this question, you have to venture deeper than yesterday’s science news and the easy lure of hyperbole. We do, in fact, live in a remarkable moment when it comes to attitudes about life and the universe – but not for the reasons you usually read about.
The palpable sense of humanity standing at the lip of some great transformation carries a special anxiety that makes our interest in aliens much more acute. The ultimate fate of civilizations on other worlds has always been part of their fascination for us. Are they long-lived or do their societies flare out after just a few thousand years? That question has recently taken on a new urgency.
In driving climate change, humanity faces an existential crisis unlike anything in our 300,000-year history. Global warming is a consequence of our becoming a true power on the planet. Our technosphere – the collective energy-intensive activity we’ve wrapped around the planet – is now driving dramatic changes in the Earth’s complex natural systems, such as its biosphere and atmosphere. That means we’ve altered the evolution of an entire planet, and now we wonder what comes next for us. But to ask if humanity can make it as a species on this planet makes one wonder if any species anywhere in the galaxy can. With climate change, the generic question about cosmic civilizations and their planetary fates suddenly becomes a lot less abstract. The answer to “Are we alone?” matters in an entirely new light.
But are we getting any closer to answering that question?
To seriously and scientifically address any issue about other civilizations in the cosmos, you have to have the time and resources to do the serious science. Nothing has stood in the way of this work like the cringeworthy history of UFOs. Sightings of unidentified flying objects have been with us since just after the Second World War, but there has never been any science to them. As astrophysicist Jason Wright points out, nobody watches the skies as much, or with better instruments, than astronomers. And while we do see things we can’t initially identify, a little detective work almost always sorts things out (spent rocket boosters and the like). So, unless you’re willing to dive into the black hole of conspiracy theories, those “lights in the sky” are a huge waste of time (and if UFOs really are aliens trying to hide, someone should tell them to turn off the running lights on their spaceships).
UFOs have driven the giggle factor, as associations with little green men have always plagued attempts to build a science focused on other civilizations. It was in 1959 that astronomer Frank Drake laid down the radio-based, signal-hunting strategy that became the “classic” mode for the search for extraterrestrial intelligence (SETI). But even as pioneering scientists such as Mr. Drake, Carl Sagan and Jill Tarter worked diligently to establish a solid scientific footing for SETI, many astronomers remained skeptical or even hostile to the endeavour.
And while NASA was enthusiastic about it for some time, in the 1980s and 1990s a series of politicians made SETI into a “waste-of-tax-dollars” punching bag. This left the space agency gun shy about funding new research. People often think astronomers have carried out exhaustive searches for extraterrestrial intelligence, but nothing could be further from the truth. We’ve barely even begun to start looking – because no one was willing to pay for the work. For decades, there has essentially been no public money for SETI and only whiffs of private funding.
Things, however, are just starting to change – for the best of reasons. New and revolutionary science has transformed our understanding of life and the universe.
While the search for intelligence in the universe was being starved to death, something remarkable happened in the study of less advanced forms of life. Beginning in the 1990s, the field of astrobiology – the study of life in its astronomical context – began piling up one revolutionary discovery after another. From the recognition that Mars was once a very wet planet to the discovery of extremophile bacteria living in the harshest conditions on Earth, astrobiology rewrote our understanding of how life and planets can go together. But the most important element of the astrobiological revolution – and the one most relevant to the study of intelligence and extraterrestrial civilizations – came with the stunning discovery of exoplanets.
The question of other planets orbiting other stars is so old that even ancient Greek philosophers beat each other up about it. Then, in 1995, we answered it when two Swiss astronomers found a Jupiter-sized world orbiting a relatively nearby star. We finally knew we were not alone, at least when it came to planets. Soon, new exoplanets were discovered on a weekly basis, including worlds in the all-important Goldilocks Zone. These were planets with temperatures just right for liquid H2O and, perhaps, life to exist. By 2010, scientists had found so many exoplanets that they could say with confidence that every star you see at night hosts at least one world. And if you count just five of those stars, one of them will have a planet in the Goldilocks Zone.
In the past few years, astrobiologists have moved past simply discovering planets wholesale. Now, the emphasis is to unpack the detailed nature of individual worlds. With sophisticated new observational techniques, we’re learning how to see the atoms and molecules making up an exoplanet’s atmosphere. The process, called atmospheric characterization, means we may be just a few decades away from having real data to argue over about life on distant worlds.
The importance of this possibility cannot be overstated. After thousands of years, and thousands of people just voicing their opinions about life in the universe, in a few decades we may have actual evidence. We can’t say which way it will point. And because it is science, years will be needed to sort out the implications. But one way or another, the exoplanet revolution means evidence in the form of carefully collected data is on its way. That is a game-changer, and it demands an end to the skepticism that can still swirl around attempts to think scientifically about extraterrestrial intelligence.
To see how this change emerges, you need to first see how atmospheric characterization actually works. Atmospheric oxygen is a consequence of Earth’s abundant life – its biosphere. Without the biosphere, the oxygen would quickly react away. That means the detection of oxygen in an exoplanet’s atmosphere might signal the presence of its own biosphere – an exo-biosphere. With a flotilla of new and more powerful telescopes on the horizon for atmospheric characterization, scientists are now readying themselves by exploring different pathways for the evolution of biospheres on other worlds. The game now is to find how different forms of alien life can leave imprints – called biosignatures – in the light we catch from those distant worlds.
But as these studies deepen, it becomes painfully obvious that staring hard at exoplanets to find biosignatures might just as easily mean we trip over evidence of something more remarkable: technosignatures. A technosignature would be any unintentional byproduct of an industrial civilization’s activity on an exoplanet. It could be atmospheric “pollution” in the form of chemicals so weird that no natural process could explain them. It could be the imprint, in reflected star light, of vast farms of solar energy collectors on a planet. It could even be the glow of city lights on an exoplanet’s night side. While all of these technosignatures are highly speculative, over the past few years, it’s become hard for detractors to say we should never consider them. In fact, being smart in science often means preparing for possibilities before you do an experiment or make observations. That way you’re ready when something new pops up.
Last fall, NASA convened a special “Technosignature Workshop” in Houston, Tex. It was the agency’s first SETI funding-oriented meeting in decades. The workshop brought more than 40 researchers like me together to help NASA map ways a scientific search for technosignatures might be carried out. But it wasn’t just the search for unintentional exo-civilization signals that were discussed. The classic form of SETI is changing, too, thanks in no small part to a US$100-million grant from Yuri Milner’s Breakthrough Listen project. Advances in artificial intelligence now allow vast amounts of data to be automatically collected, processed and screened for interesting signals.
And the rest of the world is catching on. Technosignatures were one possibility when Tabetha Boyajian and Jason Wright’s planet-hunting observations of the star KIC 8462852 showed its light rapidly dimming and returning in totally unexpected ways. The star’s behaviour was like nothing anyone had seen before. When the astronomers reported their results and considered all the different explanations (a swarm of comets, orbiting clouds of dust, etc.), they also carefully included the possibility of orbiting artificial large-scale structures on the list. It was a watershed moment, as two professional astronomers were explicitly saying, yes, an exo-civilization should be on the table at this point. The story broke via a thoughtful piece in The Atlantic by Ross Andersen, but that didn’t stop some in the world’s media from blaring breathless headlines about the discovery of alien megastructures.
Something similar happened when Harvard astronomer Avi Loeb and collaborators recently explored the possibility that Oumuamua was not an asteroid but might be an artificial “light-sail” launched by an exo-civilization. And there are still those who claim that any scientist studying exo-civilizations is just in it for the media attention. But for someone such as Prof. Loeb, the time has passed for fearing the giggle factor in talking about exo-civilizations. He is pushing boundaries because, in his view, we have come too far to not discuss them as a scientific possibility.
Astronomer Milan Cirkovic likes to emphasize how the question of other civilizations touches our deepest and most enduring questions about humanity and our place in the universe. What all the headlines about aliens demonstrate is that, culturally and scientifically, we’ve entered a new epoch in our approach to these questions. The exoplanet revolution has forced us to see that our world may be just one of many and is perhaps not so different. And with our civilization’s growing power, evidenced through climate change, we may also be ready to explore new ways of understanding the meaning of being a true planetary species. Our intense interest in other civilizations may really be a reflection of our hunger to understand what’s next for ourselves.
We are standing on a frontier when it comes to the study of life and the universe. But like all great challenges, the frontier makes demands of us. The question of alien life and civilizations is head-spinningly exciting, but the only way it will be answered is with science. And science, by design, is slow, deliberate and precise. In other words, it can be very boring. So while it is time to abandon the dismissive giggling or pointless hostility over thinking about other intelligent beings in the universe, it is also time for all of us to become savvy consumers of science news. Whatever discoveries lie ahead, they are going to be thrilling, as they change our view of ourselves and our future.
The road ahead will be long and arduous, but that is just as it should be. On all fronts, we finally have our work to do.