In October 1992, astronomers kicked off an ambitious project years in the making. Two radio telescopes, one in Puerto Rico and the other in California, started scouring the night sky for potential signals from alien civilizations somewhere deep in the cosmos.
“We begin the search,” declared Jill Tarter, the project scientist, as the telescopes started listening around glimmering stars many light-years from Earth.
A year later, the search was suddenly over. A senator from Nevada wiped out all funding for any efforts in the search for extraterrestrial intelligence, or SETI, in NASA’s budget, including this new project.
“The Great Martian Chase may finally come to an end,” declared Senator Richard Bryan, after Congress approved a NASA funding bill with zero mention of SETI. “As of today, millions have been spent and we have yet to bag a single little green fellow. Not a single Martian has said take me to your leader, and not a single flying saucer has applied for FAA approval.”
The search for extraterrestrial life, in general, would continue, of course, carried out by academic institutions around the world, by people like Tarter, one of the field’s best-known SETI researchers (and the inspiration for Ellie Arroway, the protagonist in Contact, Carl Sagan’s 1985 classic science-fiction novel). But they wouldn’t get any help from the feds.
“[Bryan] made it clear to the administration that if they came back with SETI in their budget again, it wouldn’t be good for the NASA budget,” Tarter says now. “So we instantly became the four-letter S-word that you couldn’t say at headquarters anymore, and that has stuck for quite a while.”
That could soon change. Lawmakers in the House of Representatives recently proposed legislation for NASA’s future that includes some intriguing language. The space agency, the bill recommends, should spend $10 million on the “search for technosignatures, such as radio transmissions” in the next two fiscal years.
The House bill—should it survive a vote in the House and passage in the Senate—can only make recommendations for how agencies should use federal funding. But for SETI researchers like Tarter, the fact that it even exists is thrilling. It’s the first time congressional lawmakers have proposed using federal cash to fund SETI in 25 years.
Since SETI research emerged in the United States in the 1960s, astronomers have targeted one particular signature of technology: communication signals, especially those that span a narrow range of radio frequencies. Astronomers suspect such narrow-band signals are produced, as they are here on Earth, by artificial means, and would stand out among the universe’s natural radio sources, which are mostly broadband. The hope is to detect radio signals broadcast by another civilization to attract the attention of cosmic neighbors, or maybe even eavesdrop on radio communications between two spacefaring civilizations.
Beyond that, technosignatures refer to a wide assortment of potential markers of advanced beings that could conceivably be spotted by telescopes, on the ground or in space. Perhaps other technologically advanced civilizations use laser transmissions to communicate. Maybe they have forged blast shields to protect themselves from invaders, or built enormous spheres to harness their star’s light and power their operations. Maybe, like us, they’ve lit their surfaces with shimmering city lights or padded their atmosphere with pollutants. Their worlds may be coated in layers of radioactive ash and smoke after a destructive nuclear war. With power and precise instruments, humans could someday detect these types of technosignatures—if they’re out there, of course.
In 1971, NASA asked astronomers, including Sagan, to brainstorm techniques for surveying the sky for SETI signals. They came up with an ambitious plan: the construction of a giant array of 1,000 radio telescopes. By the end of that decade, they hit a snag. Bill Proxmire, a Democratic senator from Wisconsin, gave the space agency one of his made-up Golden Fleece awards, reserved for federally funded projects he thought were useless. Proxmire then tried to terminate SETI funding altogether, but Sagan convinced him to back down.
The astronomers’ vision for a forest of telescopes never materialized, but the report they produced for NASA became the foundation for future SETI programs—including the one Tarter helped lead before it was gutted.
In the years since, SETI astronomers have depended on private sources to fund their research and operations. Often, these sources are rich people. Paul Allen, the Microsoft co-founder, donated $30 million to build the Allen Telescope Array, a collection of radio telescopes in California dedicated exclusively to SETI observations, after Tarter asked him. (The array shut down for several months in 2011, due to lack of funds.) Yuri Milner, a Russian tech billionaire, is spending $100 million over a decade on SETI research at several organizations.
As available resources for SETI shrunk, funding for the other side of the search for life—the search for biosignatures, particularly signs of early microbial life—blossomed. NASA established an astrobiology institute in 1998 and has since supported the work of dozens of research teams with millions of dollars in grants. Some of the most exciting future exploration targets in our solar system are now ocean moons like Enceladus and Europa, particularly because of their potential to house microbial life. Indeed, the chances of detecting tiny microorganisms in our own solar system are probably better than receiving a call from technologically advanced beings many light-years away.
But that doesn’t mean we should give up on supporting SETI altogether, says Avi Loeb, the chair of Harvard’s astronomy department and one of Milner’s advisers on Breakthrough Listen, the decade-long effort to fund SETI research. “I don’t see a reason to do one and not the other, because it’s also very challenging to look for primitive life,” Loeb says. “It’s not as if it’s a piece of cake, an easy task. Otherwise, we would have done it already.”
So, why now, after 25 years, do lawmakers appear willing to lift SETI’s taboo status?
The short answer is that someone in Congress is into it. The provision comes from Lamar Smith, a Republican congressman from Texas, who worked with the SETI Institute to craft the language, according to SETI researchers. Smith is a controversial figure in the scientific community because of his climate-change denial, but he is a fervent supporter of astronomy research (though he’s retiring in November). Seth Shostak, the senior astronomer at the SETI Institute in California, says Smith has visited the institute and once sat next to Shostak’s mother during a SETI talk at the Library of Congress. (Smith’s office did not confirm whether the measure originated with him, but shared a statement from the senator about astrobiology. “It’s clear that the scientific community and the public is very interested in this research,” Smith said.)
The longer, more meaningful answer has to do with how much the field of astronomy has changed in the last 25 years. Our knowledge and understanding about the cosmos has changed dramatically since Bryan’s crusade.
As humans developed more powerful telescopes and techniques, as they looked deeper into the cosmos, as far as the earliest stars, the friendlier to life, or at least the possibility of its emergence, the cosmos began to seem. When Bryan terminated NASA’s SETI funding, the only planets we know of were those in our solar system. Today, there are 3,725 known exoplanets and counting. More than 900 of those are thought to have solid, rocky surfaces like Earth. The majority of these discoveries come from Kepler, a NASA spacecraft that launched nearly a decade ago.
“Kepler showed us that planets are as common as cheap motels, so that was a step along the road to finding other life because at least there’s the real estate,” says Shostak. “That doesn’t mean there’s any life there, but at least there are planets.”
In the last few years, several astronomical discoveries have permeated major news cycles and garnered considerable attention. There was Tabby’s Star, a distant star with a jumble of objects floating around it (that astronomers later determined was probably just dust.) There was TRAPPIST-1, a system of seven planets, with several orbiting in their star’s habitable zone. And there was ‘Oumuamua, the first known interstellar object that Milner instructed astronomers to check for signs of artificial technology. They didn’t detect any, but for a time, the thought of getting a positive result, however unlikely, was exhilarating.
Since its inception, SETI has suffered from a giggle factor. Today, after 25 years of discoveries and breakthroughs and progress, the suggestion that we might someday—and perhaps someday soon—stumble upon an alien civilization, even the remains of one, doesn’t seem quite so silly anymore.
Still, the perception of SETI as unscientific and frivolous, remains in some corners, particularly on Capitol Hill, where the subject is often held up as an example of misguided government spending. During a committee hearing for the proposed legislation in April, Eddie Bernice Johnson, a Democratic congresswoman from Texas, invoked the technosignatures measure as she criticized her Republican colleagues’ for wanting to cut earth- and climate-science funding.
“Where does all this money go? The majority diverts it to searching for space aliens and to the president’s unexamined initiative to build an orbiting moon base, among other things,” Johnson said. “I wish I were joking.”
For SETI researchers, it was déjà vu. “Space aliens” is not so different from “little green men.”
As recently as January of this year, Tarter suggested a rebranding for SETI. “SETI is not the search for extraterrestrial intelligence. We can’t define intelligence, and we sure as hell don’t know how to detect it remotely,” she said. SETI “is searching for evidence of someone else’s technology. We use technology as a proxy for intelligence.” Call it SETT instead, she said.
Tarter spoke at a meeting of the National Academy of Sciences’ Committee on Astrobiology Science Strategy for the Search for Life in the Universe—a desperately long name for a group that collects input from scientists about what the United States should study next. She and several other representatives of SETI organizations submitted a report to the committee to reconsider NASA policy, which currently doesn’t recognize SETI as part of astrobiology.
“This is an arbitrary distinction that artificially limits the selection of appropriate tools for astrobiology to employ in the search for life beyond Earth, one that it is not supported scientifically,” they wrote. “The science of astrobiology recognizes life as a continuum from microbes to mathematicians.”
With the House bill on the table, Tarter says she will do what she can, as she has for years, to rally support among the decision-makers, especially the people who hold the purse strings. SETI needs funding from both private and government sources, she says. And, after years of starts and stops, triumphs and disappointments, SETI needs consistency.
“$10 million at once for one year won’t do much,” Tarter said. “But $10 million a year, as an ongoing funding stream, could do a great deal. It could allow people to build special-purpose instrumentation, and then use it on the sky for a long time.”
Emphasis on a long time. Astronomers have spent about 60 years—a negligible amount of time in cosmic terms—searching for signs of intelligent alien life in a tiny fraction of the observable universe. They’ve barely begun the search.
“So far we’ve examined in detail one glass of water out of the ocean,” Tarter said. “If your question was, are there fish in the ocean?, and you scooped up a glass and you looked in it and you didn’t find a fish … I don’t think you’d conclude that there are no fish in the ocean.”