What Happens If We Detect Extraterrestrial Intelligence?

Finding communicative aliens is a long shot, but if we do, here are a few next steps to consider.

The Green Bank Telescope. Photo by eawortman/flickr/CC BY-NC-SA 2.0

Fifty-six years ago, in a remote West Virginian wilderness, astronomer Frank Drake carved out some time with the Green Bank Telescope—the world’s largest fully steerable radio telescope—to search for signs of communicative aliens. Six hours a day for several months, his team scanned the skies for signals from two nearby, sun-like stars—Tau Ceti and Epsilon Eridani. Though the team turned up nothing but static, they set a precedent for a search for extraterrestrial intelligence (SETI) that continues today.

The Green Bank Telescope is now getting a SETI-centered update, thanks to the Breakthrough Listen project, “the world’s most comprehensive, sensitive, and intensive search for extraterrestrial intelligence in history,” according to its head of science, Andrew Siemion, who’s also the director of the Berkeley SETI Research Center at the University of California, Berkeley.

Green Bank is a powerful scope, capable of scanning billions of radio frequencies, from the 100 megahertz range all the way up to 100 gigahertz. Now, Breakthrough Listen is currently equipping the telescope with new electronics so that it can peruse those frequencies more efficiently.

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Siemion is part of a trio of researchers that’s currently using Green Bank to conduct a SETI investigation focused on a star located nearly 1,500 light-years away, in a swan-shaped constellation called Cygnus. It’s been in the news a lot over the past year for some seriously strange behavior.

In early 2016, an international team of researchers published a paper in Monthly Notices of the Royal Astronomical Society describing how, over the course of several years, the star—KIC 8462852 (also known as “Boyajian’s Star,” for the paper’s lead author, Tabetha Boyajian)—revealed inexplicable dips in brightness that lasted for a few days to nearly three months. In a couple cases, its brightness waned by about 20 percent, an amount likely too large to peg on an orbiting planet.

What’s more, over the past year, other researchers have uncovered another anomaly: Boyajian’s Star seems to be losing luster over time. One study reported that dimming has occurred over the course of a century (another paper rebutted that claim), while a more recent study looked at the four years that the Kepler Telescope observed the star (2009-2013) and also discovered sustained loss of light. The thing is, Boyajian’s Star is a main sequence star, meaning that it should steadily burn until entering its death throes.

If long-term dimming is indeed occurring, then whatever’s causing it is also probably causing the temporary dips in the star’s luminosity, says Boyajian, who was a post-doc at Yale when her paper came out and is now an assistant professor of astrophysics at Louisiana State University. “Basically, whatever theory you come up with to explain one [phenomenon] has to actually explain both of them, just due to Occam’s razor” (the idea that the simplest of two competing theories is preferred), she says.

So far, no one has developed a convincing astrophysical explanation for both the dimming and the dips, leading some researchers to broach the idea that alien-built structures might be responsible for the star’s peculiar behavior. One general idea is that otherworldly beings are harnessing KIC 8462852’s light to power starships (which could explain the dimming), and in so doing, periodically obscuring its brightness as they orbit (which could explain the dips).

While Boyajian was at first hesitant to engage in conversation about aliens, curiosity finally got the better of her. The star seemed a worthy candidate for a SETI investigation, so she and her colleague, Penn State astronomer Jason Wright (who co-authored a paper suggesting that KIC 8462852’s weird light curve could be indicative of a “swarm” of artificial megastructures ) asked Siemion to join them in putting together a proposal.

“KIC 8462852 is a very, very interesting star. It’s a singular object in astronomy. We know of no other object—no other star—that is like it,” says Siemion. “So that makes it intrinsically very exciting for astronomy, and, I think, also very exciting for SETI.”

The odds of finding intelligent life circling Boyajian’s Star (or any place else, for that matter) are, in a word, slim.

“It’s a one in a million shot,” says Boyajian, but “why not look?” After all, whether or not we’re alone in the universe is arguably the biggest question humanity faces.

But say that, one day, researchers actually do find a signal—either from Boyajian’s star or from somewhere else—and that other scientists verify it as the product of something undisputedly extraterrestrial and intelligent. Then what?

Let’s get one thing out of the way: The feds won’t try to cover it up. “The government has never shown any interest in any signals we’ve gotten. Even in 1997, when we had a signal that we thought might be real,” says Seth Shostak, a senior astronomer at the SETI Institute in Mountain View, California.

Rather, if such a discovery is made, “it will be a very messy business,” he says. “It will be a very chaotic unveiling of this story, because there’s no policy of secrecy in the whole SETI enterprise, and that means that every time you get a signal that looks the least bit promising, the media are on it.”

Many people won’t be surprised by the news. For instance, a 2015 poll conducted by YouGov found that more than half of American respondents think that intelligent life exists. And some people, Shostak adds, believe that aliens have already visited our planet. (They haven’t.)

But for others, “there may be a sense that our specialness is going to be challenged,” says Douglas Vakoch, president of METI International, which researches how to construct interstellar messages (METI stands for Messaging Extraterrestrial Intelligence). “I think it would be easy to fall into a cosmic inferiority complex,” he says, particularly because, considering the brief timespan we earthlings have been communicative, the civilization we encounter is likely to be much more technologically advanced.

And if that’s the case, they already know that we’re here.

“Our radio signals, our TV signals are leaking off into space, and so anyone who’s looking for artificial signals similar to the kind of signals we look for in our radio SETI searches should be able to detect those, if they’re even [just] a couple hundred years more advanced than we are,” says Vakoch.

“In some ways, any message we get from an extraterrestrial will be like a cosmic Rorschach ink blot test.”

According to Vakoch, we should ask ourselves, “do we want to be content with the accidental messages that we’re giving them, or do we want to put our best foot forward” by sending a tailored reply to our intergalactic neighbors?

Controversy surrounds the issue. For instance, some researchers think that using a high-powered telescope to fire off a painstakingly crafted message to another civilization is a waste of resources. Others worry that such a strong signal could antagonize the aliens. (And to be clear, we’ve space-mailed missives in the past, just not to anyone specific. In 1974, for instance, Frank Drake was involved in crafting a message that was beamed out from the Arecibo Observatory, the world’s largest single-dish radio telescope. )

Vakoch, for one, favors responding, and suggests that we begin by acknowledging receipt, so to speak. “What we might want to do is start by replaying whatever it was that they sent so that they would recognize it and say, ‘Aha! This is not just another sitcom or the nightly news, but they actually got our signal,’” he says.

Whatever we send after that should be delivered in a language more universal than, say, English—it’s highly unlikely they’d understand our languages, says Vakoch. He suggests we relay a message built on basic math, reasoning that if the aliens are smart enough to send and receive a signal, “they probably know that one plus one equals two.”

Of course, engaging in a game of interstellar telephone will take some time. Given that our nearest star (after the sun) is located about 4.2 light-years away, “the round-trip exchange is at a minimum just under a decade, but it could be hundreds or thousands of years if the target is a very distant star,” says Vakoch. (If we detect life around Boyajian’s Star, for instance, sending a message and receiving another in reply—if they even deign to respond—would take about 3,000 years.)

And we may never figure out what they’re telling us. “There’s going to be a lot of guesswork in trying to interpret another civilization. In some ways, any message we get from an extraterrestrial will be like a cosmic Rorschach ink blot test,” says Vakoch.

But, he adds, “if we could really come to understand another civilization in its own terms, we would have our awareness opened up to a radically new way of encountering the universe.”

In the search for intelligent life, it’s important to remember that the absence of signals doesn’t prove that extraterrestrial organisms don’t exist.

Indeed, our own galaxy is teeming with precursors to life—“polycyclic aromatic hydrocarbons, carbon chains, precursors to amino acids, they are everywhere,” says exoplanet hunter Debra Fischer, an astronomy professor at Yale University and a co-author on the paper about KIC 8462852’s light dips.

“Biochemists are beginning to understand that life may have been a natural outcome—not a freak accident—of prebiotic chemistry, given the conditions on Earth,” she says. And for that reason, “it seems likely that biological organisms will evolve on some fraction of worlds that are similar to the Earth.”

Most life in the universe likely isn’t of the intelligent sort, however. Rather, it probably consists of primitive organisms like the kind that dominated the surface of our planet for the majority of its history. If that’s the case, they obviously won’t be sending us any transmissions, so we’ll have to find them through other means.

Regardless of the outcome, the quest after E.T. is revelatory, says Vakoch. “I think the whole prospect of searching, whether we find them or not, forces us to look at ourselves more clearly, to think about how do we encounter the world, how do we make sense of the world, what do we value in the world, what would we want to share about the world.” Ultimately, the search is within.


*This article was updated on November 30, 2016, with the following correction: The nearest star to us (besides our sun) is about 4.2 light-years away, not 4.5, as originally stated.

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About Julie Leibach

Julie Leibach is a freelance science journalist and the former managing editor of online content for Science Friday.

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