It’s late on a clear night. You’re driving down a winding county highway—no headlights for miles—and you steer the car over to the shoulder. You get out, wait for the dome light to blink off, and actually look up at that sky for the first time in a while. The stars shine down in patterns humans have tried to make sense of for millennia. There are so many of them, each a slightly or much bigger or smaller version of the sun, burning very far away.
Whoa, you think.
Around most of them, planets orbit, slightly or much bigger or smaller versions of those in our solar system.
Also whoa, you think.
And then, weirded out, you think some more. “Is anybody out there?” you shout, like you might if you suspect someone’s inside your house, but this time you’re yelling at the speckled darkness.
You’re being ridiculous: Nobody’s going to answer you tonight. But Science might answer your question someday. Researchers are trying to find evidence of smart aliens, and have been trying for around 60 years. Still, the work they’ve done so far barely registers on the cosmic scale. Space is very big—the stars you can see are a tiny fraction of the ones just in our own galaxy. And intelligent aliens, if they exist, could be sending a message, or spewing inadvertent signals, on any frequency. Or they could be using gravitational waves, or neutrinos, or dark matter, or some phenomenon humans haven’t discovered yet to get our attention or communicate with each other. Who knows!
Astronomers recently revised the estimate of their progress in scouring the universe for fingerprints of alien technology (including just the search for radio waves). They’ve sampled a portion of the galaxy equivalent to a hot tub’s worth of ocean water. Congratulations, SETI!
But since it would take 166,875,000,000,000,000 hot tubs to fill the ocean, you might wonder why SETI scientists even bother.
Well, the thing is that, if smart extraterrestrials are out there, and if humans ever find them, it’s statistically likely their civilization will be a lot older than ours. And given that extra time in existence, they’ll probably have much radder innovations, ones we would barely be able to fathom (wormhole borers, consciousness stored on silicon, social media companies with consciences). Those inventions might fall under science fiction author Arthur C. Clarke’s Third Law: “Any sufficiently advanced technology may be indistinguishable from magic.”
SETI is, in that way, the scientific version of the search for a god. What is a god, after all, if not a powerful, superior being who represents the best version of us, and inhabits a plane of existence we could ascend to given enough time and trials? The aliengods, according to many SETI scientists’ logic, would not be like the bickering, petty, vengeful deities of the ancient-Greek variety: If they have lived long enough to both grow old and maintain technological prowess, they must have figured out how to use their resources sustainably, not throw their planet’s climate out of whack, avoid nuclear annihilation, and generally deescalate whatever counts as an alien conflict. They give us hope that we could invent their technology. We could learn to get along. We could learn to steward a planet. We could grow up to be them.
If we could find them, we could end our history-long loneliness, and we could imagine—through the example of their very existence—that we, too, could make it to some kind of higher, more heavenly reality.
That is not quite how scientists tend to frame their work. And they do not tend to say that it requires faith, either. An outside observer might think that SETI scientists believe in ET—otherwise, why would they spend years searching? But most actually reserve judgment, and maintain at least outward agnosticism. What keeps most motivated is not belief, or dogmatic pursuit of a foregone conclusion, but the importance of the potential discovery: There’s a low probability any given scientist in any given era will succeed in finding alien life, but—if they do—the consequences are significant. You know, like transforming our conception of life, the universe, and everything.
Despite the magnitude of that potential finding, federal science has mostly left SETI out of its spreadsheets for decades. But in a 2018 reversal, NASA hosted a workshop to determine how best to search for alien technology. And outside of that support, scientists have also started a slew of new projects, and begun training more fledgling researchers. The alien hunt, in other words, is having a bit of a moment.
The History of the Hunt for Aliens
It all began in the middle of nowhere: Green Bank, West Virginia. The site’s remoteness is precisely why, in the 1950s, astronomers decided to build radio telescopes way out here, far from the contaminating influence of human technology. One of Green Bank’s early employees was a man named Frank Drake. Drake, like many scientists, read a 1959 Nature paper by physicists Guiseppe Cocconi and Philip Morrison, who suggested that if a person wanted to find intelligent aliens (here, “intelligent” means capable of using technology to transmit an identifiable signal) they might try picking up radio broadcasts, and they suggested a range of frequencies scientists could search. This fired Drake up, and in 1960 the observatory’s director agreed to let him point an 85-foot telescope at two sun-esque stars, tuning it in to the kinds of transmissions that could come from technology and not from stars, gas, or galaxies.
It didn’t, but the effort, called Project Ozma, kicked off the modern SETI enterprise. A year later, Green Bank hosted a secret National Academy of Sciences meeting at which Drake presented the now-famous and now-eponymous Drake Equation. It posits that if you know how often stars are born in the galaxy, what percentage have planets, what number of those planets are habitable, what fraction of habitable planets are inhabited, what fraction of inhabitants are intelligent, what fraction develop interstellar communication, and how long technologically intelligent civilizations survive, you could figure out how many extraterrestrial societies await your discovery. It was never meant to be be precise math: It was just a meeting agenda.
Around a decade later, NASA convened a study called “Project Cyclops.” In it, scientists laid out what alien contact might look like and how, engineering-wise, they might accomplish it. They devised a hypothetical radio telescope made of many antennas that work together as one. While at full scale, it would be cost between $36 billion and $60 billion in 2018 dollars, the attendees suggested it be made in modular fashion—a few antennas here, check for aliens. No aliens? Add a few more, look some more. Still nothing? Break ground again. Etc.
The project never happened, but it did inspire Berkeley professor Stuart Bowyer and Berkeley student Jill Tarter to start a smaller-scale program called SERENDIP: the Search for Extraterrestrial Radio Emissions from Nearby Developed Intelligent Populations. Berkeley now has a SETI Research Center, and SERENDIP still exists—in its sixth iteration, using both the Green Bank Telescope and the Arecibo telescope in Puerto Rico. Since the turn of the century, the program has also let you help process data through the SETI@Home program, which uses your idle CPU to hunt for potential communications.
In the 70s, Ohio State started a SETI project at its Big Ear Observatory, and caught the famous WOW! Signal—a mysterious burst of radio waves that has captured attention for decades but, sorry, is not aliens. For a while, NASA had a nascent SETI program, and when it officially began operations in 1992, astronomers had good reason to hope for a “hello” from light-years away: Around this time, scientists discovered the first-ever planet beyond our solar system, around a pulsar, and would soon find another one, this time orbiting a star like the Sun. All those aliens, turns out, might have at least a few places to live. Plus, back on Earth, scientists were learning more about the badass microbes that live in hot, cold, acidic, basic, salty, radioactive, and just generally unpleasant spots. If life could find a way in all that mess, why not around Zeta Reticuli?
But politicians did not always favor pursuit of such extraterrestrials, extremophile and/or intelligent and/or otherwise. And the next year, Congress voted to terminate the NASA project’s funding.
Since then—a little more than 25 years ago—NASA has had no SETI programs. Scientists, though, aren’t easy to stop—especially not when the end result of their quest could be some kind of cosmic salvation. And so the former NASA team privatized their efforts, and began a program called Project Phoenix, backed by some of Silicon Valley’s early tycoons. For nine years, from 1995-2004, they did the work they’d planned to do under NASA’s banner on their own terms, through the nonprofit SETI Institute. From Arecibo, Green Bank, Jodrell Bank Observatory in England, and the Parkes radio telescope in Australia, they sought after radio broadcasts from the great beyond.
After the dawn of the new millennium, the SETI Institute built its own telescope in partnership with Berkeley, funded by the late Paul Allen. While the team intended to construct 350 antennas, cost overruns mean the Allen Telescope Array stopped at 42 dishes. In 2011, Berkeley and the Institute parted ways, and SRI—one of those big-time defense-oriented nonprofits, and also the one that did the DoD’s men-who-stare-at-goats projects—operates the telescope for the SETI Institute, sharing observation time with the scientists.
Today, these scientists aim the antennas at friendly-seeming planets the Kepler Space Telescope has found, nearby dwarf-star systems, and whatever some scientist says is weird and so is (maybe, perhaps) aliens.
The Institute now has company, though: In 2015, billionaire Yuri Milner announced that he was giving $100 million to other SETI scientists, to look for extraterrestrial radio and lasery signals over the next 10 years. Today, strangely, the same scientist—Andrew Siemion—leads both the SETI Institute’s alien-hunting division and Milner’s Breakthrough Listen program.
That’s not quite the consolidation of power it would have been just a few years ago—because more groups are turning their scopes skyward and searching for smart life. Astronomer Shelley Wright leads a laser search called NIROSETI from the University of California, San Diego, and her team is starting up a wide-view search called PANOSETI. An organization called METI International, meanwhile, also does optical searches, primarily with the Boquete Observatory in Panama and with volunteers’ personally owned telescopes. UC Santa Barbara scientists are planning the Trillion Planet Survey, to look for extremely energetic signs of smart life.. At Penn State, astronomer Jason Wright helped start the PSETI Center, which does research and has a formalized SETI education program. Telescopes in Sardinia, the Netherlands, and Western Australia have also done some looking.
In short, the people searching for smart aliens are multiplying. Which is good for any field’s research trajectory: the more minds you have in more different places having different conversations and making different plans, the more creative and diverse your strategy set will be. That’s particularly important for SETI, given that we know legit little about if and how all this seeking might turn into a find.
The Future of Aliens
In addition to these new programs, the US government has also been more interested than usual in hunting down alien “technosignatures”—the signals that might come from extraterrestrial technology. In April 2018, Congress expressed a desire for NASA to fold technosignature searches into its schemes (the agency already has robust “biosignature” search plans, to look for chemical signs of life dumb or smart). That desire made its way into the 2018 Authorization Act. And, official interest in hand, NASA held a workshop to investigate where SETI stands, what research paths seem most potentially fruitful, and what outside partnerships might be helpful. The October meeting, livestreamed on NASA TV, had hundreds of watchers, and a Reddit AMA netted 234 comments.
In the official report, scientists noted which kinds of technosignatures deserve focus, laying out the options on one of those hot-or-not-type charts you often seen at the backs of magazines. The axes: “scientific” and “practical.” Ideal signals optimize the combination of the two.
Those optimal technosignatures could be found with near-term, not-too-costly technology. And they should be signals that aren’t too ephemeral (so not spaceships shifting into warp drive), and that don’t require aliens to decide to talk at us (so not a welcome beacon). Bright/loud signatures that are unambiguous and packed with info are ideal, and the quest for them should, as a side effect, produce scientific results other fields can use.
Done and done.
The report goes on to list modern techno-search programs—and how traditional telescopes, doing non-alien astronomy, could help the SETI effort without much extra effort themselves. With the field moving more from fringe to center, that kind of collaboration might be more likely to happen in the future. And with advances in data analysis, telescopes can become better anomaly detectors, and astronomers can better find things that make them go “huh.” No “huh” has yet been aliens, but one, someday, might be.
A lot of these “huh” signals have been in the news recently. There’s the ’Oumuamua rock that Harvard astronomer Avi Loeb insists could be an interstellar spaceship but is probably an interstellar asteroid. Then there’s Tabby’s Star, which has something in its orbit that blocks its light. Some astronomers suggested the something could be an “alien megastructure,” but it’s almost certainly just a whole lot of dust. Don’t forget the WOW!-like burst that was just a satellite, and the ultrapowerful “fast radio bursts” that we still don’t understand but also almost certainly aren’t aliens.
Public discussion of these strange signals sometimes veers into the irresponsible. But—in an ideal world—presenting “maybe aliens” as a hypothesis (one among the much more plausible mundane explanations) is a useful exercise. And one day, “but it’s aliens” could be the right answer, instead of just the stuff of Giorgio A. Tsoukalos memes.
After all, even the serious scientists at the NASA workshop considered out-there possibilities for making contact. And that is, really, a sign of maturation: SETI began as a radio endeavor, became additionally an optical endeavor, and is diversifying beyond the “traditional” signals it sought in both regimes.
Maybe, the NASA-sponsored group suggested, scientists could find physical artifacts in the solar system—the alien version of the Voyager Golden Records that scientists shipped off from Earth in the 1970s. Maybe as our artificial intelligence matures, it’ll be better able to recognize alien AI (whatever that means). Megastructures could truly be out there, even if Tabby’s star didn’t have one. Planetary surfaces could have a “network of alien civilization heat islands”—cities, essentially, showing up as solar-energy stations. They could also have artificial light sources, like much more powerful versions of the fake Moon China has proposed. Or they could have engineered multiple planets in their solar system to have similar characteristics.
Mostly, though, scientists don’t know what aliens might do, or how to detect them. Finding hypothetical space beings could happen the way your grandma always told you you’d find love: when and where you’re not looking for it. But like you probably did, despite your grandma’s advice, SETI scientists are going to keep looking anyway—and hoping, if not believing, that someday they’ll find what they’re looking for.
Unlike your quest for love, though, SETI may be a many-generational endeavor, demanding that scientists keep projects going, and keep track of them, for an undetermined but possible large number of years. To endure, they’ll need people who know what they’re doing, which is why Penn State has started its PSETI Center, with an undergrad-through-PhD SETI curriculum (a thing that has never existed anywhere). They’ll also need stable funding, with which NASA’s still-semi-tenuous interest helps (billionaires may be great backers for a while, but ultimately, their whims can whip in a different direction). And they have to keep track of where they’ve been so they know where they’re going, which is why the SETI Institute recently launched its TechnoSearch database, which will host queryable records of work past, present, and future.
That time-machine database may only contain a hot tub’s worth of the SETI sea—less, really, when you consider all the options beyond radio waves. But astronomers are filling new containers faster than ever. And maybe someday, in a community-pool-sized container of observations, they’ll find something swimming.
Green Bank Observatory Embraces Its Alien-Hunting Future
The search for ET started in 1960, in a tiny Appalachian telescope-town. Today, that same observatory is a big part of a $100 million SETI program called Breakthrough Listen.
NASA’s New Top Astrobiologist Is Spelunking for Alien Life on Earth
To learn about the strange forms way-foreign biology might take, scientists turn to the extreme spots on Earth, and the extreme microbes that live in conditions not totally dissimilar from those on other planets.
An Astrobiologist’s Plan to Find Life on Mars
Those planets might not even be that far away. One SETI Institute astrobiologist still holds out hope for the Red Planet.
E.T. Hunters Join Forces to Probe the Heavens
Traditional astronomers have sometimes, historically, turned up their noses at SETI. But because the galaxy’s many planets have helped make the hunt for aliens more acceptable, the two groups are finding ways to work together.
METI’s First Message Is Music for Aliens
Humans don’t just wait for extraterrestrial messages to arrive, unprompted, all the time. Sometimes, we send out our own, to whoever’s listening.
Last updated June 4, 2019.
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