Yet there are some who feel strongly that he has been speaking out of turn. And they would like the rest of us to get involved. Some members of the SETI community were offended by Zaitsev’s efforts to initiate galactic conversation without at least first attempting to consult with the people of Earth.
The conflict came to a boil in October 2006, at a SETI meeting in Valencia, Spain, where there was a debate over active SETI and a contentious vote over new guidelines for initiating broadcasts from Earth. Later that month, Nature published a scolding editorial criticizing the SETI community for a lack of openness. According to the Nature editors,
the risk posed by active SETI is real. It is not obvious that all extraterrestrial civilizations will be benign—or that contact with even a benign one would not have serious repercussions for people here on Earth… yet the Valencia meeting voted against trying to set up any process for deliberating over the style or content of any spontaneous outgoing messages. In effect, anyone with a big enough dish can appoint themselves ambassador for Earth.
The SETI community should assess [the risks] in a discussion that is open and transparent enough for outsiders to listen to and, if so moved, to actively participate.
As a lifelong SETI enthusiast, I found it disconcerting to see the field so publicly chewed out. I reached out to several of the people involved to see if I could understand what had happened.
The Barn Door
Zaitsev, and other proponents of active SETI, like to point out that Earth has already been sending out radio broadcasts. So, in effect, we’ve already outed ourselves. As Sagan and Shklovsky put it in their 1966 book,
It is of no use to maintain an interstellar radio silence; the signal has already been sent. Forty light years out from Earth, the news of a new technical civilization is winging its way among the stars. If there are beings out there… they will know of it, whether for good or for ill.
This is often called the “barn door objection,” as in: it doesn’t do any good to close the door once the horse has already left the barn. We no longer have the choice to evade detection. The aliens are already learning all about us by watching The Brady Bunch and Gilligan’s Island.
Yet this does not persuade those who urge caution. It is true that an unstoppable sphere of radio signals is spreading out from Earth, its radius growing at the speed of light. Since Shklovsky and Sagan wrote the words above, it has traveled another fifty light-years. So isn’t it too late? That depends on how sensitive the alien radio detectors are. Our television signals are diffuse and not targeted at any star system. It would take a huge antenna, much larger than anything we’ve built or planned, to pick up on them. From a radio point of view our planet is not completely hidden, but it is hardly conspicuous. This could easily change. Targeted messages sent directly toward nearby stars would cause Earth suddenly to turn on like a spotlight, becoming an obvious beacon announcing, for better or worse, “We are here!” So, while it’s true that we no longer have the choice of maintaining complete radio silence, it is also true that programs such as Zaitsev’s, if continued and vastly expanded, would fundamentally change the radio visibility of our planet. We would go from barely detectable to highly conspicuous for any alien SETI programs.
In fact, several targeted radio messages have already been sent, and are racing through space, unstoppable, toward their selected destinations. The first, “the Arecibo message,” was sent by Frank Drake from the massive radio telescope (Earth’s largest) in Arecibo, Puerto Rico, on November 16, 1974. The message, designed by Drake and Sagan, contained digitally encoded two-dimensional pictographs of some simple math (to get the small talk out of the way), amino acids, DNA, stick figure humans, the solar system, and a radio telescope. In the extremely narrow direction of the beam, the Arecibo message was the most powerful signal ever sent from Earth. It was aimed at M13, a globular star cluster about twenty-five thousand light-years away—which means that, at the earliest, we can expect a reply in fifty thousand years.
The Arecibo broadcast lasted all of 169 seconds and was never repeated. So even if someday it fortuitously crossed the receivers of alien radio astronomers, they might dismiss it as a momentary fluke. We would. Our current detection and verification protocols acknowledge only repeating or long-term continuous messages. In order to avoid hoaxes, mistakes, and false alarms, if we see something fleeting that seems like a possible message, we immediately try to get a repeat observation. If we can’t, we don’t consider it to have been a bona fide detection, no matter how promising it first seemed. So, as clever and powerful as Drake’s broadcast is, if we caught a whisper of something similar, coming at us from a distant star cluster, we might not declare a successful SETI discovery. Earth astronomers seeing such a brief and powerful pulse of seeming coherence might say, “Wow! What was that?!” but probably not “Get me the White House!”*
Drake’s message may never get the attention of extraterrestrial astronomers, but it was certainly noticed by Earth’s astronomy community and the wider public. It elicited a furious letter of protest from Nobel laureate and British astronomer royal, Sir Martin Ryle, who described the transmission as reckless because “any creatures out there might be malevolent, or hungry,” and called for an international ban on any further broadcasts. The editors of the New York Times (November 22, 1976) responded with an editorial entitled “Should Mankind Hide?” arguing that, “On balance, the chances of gain from communication with alien intelligence greatly exceed the chances of harm”; that “the universe seems too rich to require an advanced race to look hungrily on Earth’s meager patrimony”; and that “Despite Sir Martin’s eminence there is no reason to assume that alien intelligence among the stars must be hostile or predatory.”
In reality, Drake’s Arecibo broadcast was more of a demonstration project than a real attempt to open a cosmic communication channel. As a symbolic stunt to show off the reality of SETI technology and message construction theory, it worked brilliantly. In recent years, however, Drake has said he regrets sending this message. He sees it as pointless and frivolous, likely to add to misconceptions about SETI and to distract from the important work, which to him means continued and expanded search programs.
Danger
There are really three reasons that SETI might possibly be best advised to maintain a listen-only policy. The first is practical: the expected asymmetry between our capabilities and those of any other civilizations. As I discuss in the previous chapter, it is likely that young civilizations will have more success in listening than broadcasting. Second is the possible threat to SETI itself from a public perception of putting humanity at risk. SETI has always had to worry about respectability. Even back at Byurakan II, in 1971, there was discussion about downplaying any perception of risk so as not to threaten public support. One Soviet participant urged that:
There is nothing more dangerous than to speak about the danger of communication… If we would like not to lose off the problem all together, forever, our obligation is, I feel, to stress that, in any sensible way, this problem has no danger for human society. I believe we can give a full guarantee of this.
Third, also as discussed in the previous chapter, there is the possibility that real danger may lurk.
Yet what are we really worried about? Alien invaders? Unfortunately, it is hard to raise this possibility without invoking associations with bad science fiction. The problem with movie aliens is that they are generally just minor variations on Earth life. Creatures from planets around other stars will be products of alien evolutionary convolutions. They are not going to come eat us or subject us to cruel sexual slavery. Still, there are some contact scenarios that cannot be entirely dismissed, in which meeting up with an alien civilization would be dangerous or disastrous. This ground has been explored in numerous scientific papers and in decades of good “hard science fiction,” the branch of SF literature whose writers and readers pride themselves on, even in their wild imaginings, being constrained by science and logic. In fact, on
e of the most adamant and vocal opponents of laissez-faire active SETI is a well-known science-fiction writer. David Brin has published both peer-reviewed astronomy papers and award-winning, best-selling science-fiction novels, including The Postman, which was made into a Hollywood movie starring Kevin Costner. Brin—that’s Dr. Brin to you—has a PhD in planetary astronomy, and his fiction draws on a solid background in physics and astronomy coupled with a freewheeling imaginative mind. Nobody alive today better represents the convergence of hard science and fictional speculation.
I first met Brin at a space resources workshop at the Scripps Research Institute in summer 1984, when I was in grad school and he was collaborating with my adviser, John Lewis, on a study about mining asteroids.1 Back then he was already a famous sci-fi writer, and in the decades since, I have enjoyed watching his star rising further. In 2007, when I learned he had become embroiled in the controversy over active SETI, I contacted him by e-mail, reminded him that we had met twenty-three years earlier, dropped John Lewis’s name (to make sure he knew I was not just another fanboy), and asked if I could call him to discuss the issue.
When we first spoke, he had just returned home to California from science-fiction conferences in Japan and China. He was obviously multitasking when he answered the phone, judging from the sounds of rustling, typing, and padding about. Yet he answered my questions in thoughtful, measured, fully composed paragraphs. His ability to do this, speak in paragraphs that seemed as if they had been written and carefully edited, reminded me of Sagan’s.
Brin pointed out to me that he is “familiar with literally hundreds of contact scenarios.” This is why, he said, “if there ever is a delegation of people chosen to first meet with the aliens, there should be some science-fiction writers among them.”
In Brin’s widely referenced 1983 paper, “The Great Silence,” he provided a thorough taxonomy of Fermi answers. These include the more disturbing possibilities that I described above as Fermi Answer 6: that nobody is on the air because there is something out there that seeks and destroys everyone who broadcasts, or everyone is being quiet because they are aware of, or concerned about, some threat. As long as we cannot dismiss these possibilities, shouldn’t we think twice before we naïvely start transmitting loudly in search of conversation?
Brin points out, rightly, that those using the “barn door” defense of METI to justify new broadcasts are being inconsistent. On the one hand, they deny that they are creating any additional risk because they claim that Earth is already widely observable due to our “leakage.” On the other hand, they want to start dedicated broadcasts in order to get the attention of ETIs who have not yet noticed us. If they believe that they can change Earth’s visibility (which is, after all the point), how can they also claim that Earth is already completely visible to anyone out there?
Another tactic used by METI proponents that really annoys Brin is to ridicule his concerns with references to all the silly sci-fi movies about evil aliens—or, as he puts it, by reducing all the subtle and sophisticated arguments that can be found in the literature expressing concern about METI dangers to “fear of slathering Cardassian invaders.”
On the other side of the debate is Seth Shostak, from the SETI Institute. A handsome man with a graying Beatle haircut, Seth is quick-witted, gregarious, bright, and charismatic.* He has been involved in the science and policy of SETI for many years, but given his outstanding communication and media skills, he has increasingly taken on the role of public spokesman for the institute and, seemingly, for SETI in general. This is not always an easy task, given that “aliens” are such a cultural lightning rod and that the SETI Institute is dependent on the largesse of private donors. As comfortable answering questions from New Agers on Art Bell’s Coast to Coast AM as he is speaking to the intelligentsia on NPR, Shostak skillfully uses humor to disarm potential critics and defuse tensions, while also retaining the gravitas of quantitative, skeptical science.
When I asked him about the uproar surrounding active SETI, Shostak insisted that Nature got it wrong in their editorial, that in Valencia there was no organized effort to encourage active SETI broadcasts or to discourage open and transparent debate about the wisdom of sending signals. Others clearly saw it differently, and felt that the mainstream SETI community was tacitly endorsing rogue broadcasters such as Zaitsev, and failing to consult the wider communities who have a stake in the way Earth represents itself (namely, everybody).
Back in the Former USSR
Meanwhile, Alexander Zaitsev was not waiting for any stinking international consultations. He had already begun sending greetings to the stars, at least to a few of them. Later that fall, in October 2007, I finally met Zaitsev in person, when the science team for a spacecraft I was working on met in Moscow. Our meeting was timed to coincide with the fiftieth anniversary of the launch of Sputnik, and the Russian space agency, hurting since the collapse of the Soviet Union but justifiably proud of their history, pulled out all the stops to celebrate the anniversary. Speeches and performances showcased the strangely mixed legacy of the space race, when humanity’s beautiful dreams of reaching beyond Earth first soared on rockets fueled by threats of destruction and doomsday. In the surreal, larger-than-life, space deco environs of the Russian Academy of Sciences—I kept thinking, “Have I been transported to the Klingon embassy?”—we were treated to military marches, folk dance performances, and speeches interspersing Tsiolkovsky’s futuristic utopian schemes about humankind’s cosmic destiny with nostalgia about the Cold War.
Sasha Zaitsev is considered by some in the SETI field to be an irresponsible and irritating rogue operator. But—what can I say? I like the guy. Kind and bright, he was a good host. He walked me around town, showing me the sprawling Moscow House of Teen Activity youth center where, in 2001, he worked with a group of at-risk teenagers to create the “Teen Age Message to the Stars.” This included greetings in Russian and English,* simple pictograms portraying Earth and its location in the galaxy, and idealized images of human family life, including a child holding hands with two parents. The Teen Age Message also included a fifteen-minute theremin concert for aliens, with classical and folk musical selections chosen by the teens. According to Zaitsev, the theremin is the ideal instrument for interstellar concerts because it consists of a simple sinusoidal wave easily converted from a radio signal back into sound. We might add that, conveniently for the only audience the Message is sure to get, it is instantly recognizable as the spacey instrument used in the music for the original Star Trek series. Teen Age Message was broadcast in August and September 2001, from the seventy-meter radio dish of Yevpatoria Deep Space Center in Crimea, aimed toward six Sun-like stars (selected with the help of the teenagers) at distances between forty-five and seventy light-years.
Zaitsev invited me to give a seminar to his colleagues at the famed Sternberg Astronomical Institute, where Iosif Shklovsky worked throughout his career and where SETI research continues today. Walking there, across a city square with boom-box-toting teens doing skateboard tricks off a Lenin statue, past elegant old Russian Orthodox churches coexisting with McDonald’s restaurants, I thought of the dampened but simmering historical conflicts between our societies. In an elegant wood-paneled auditorium that felt out of another time, I scrawled a few equations on the blackboard—yes, a real chalk-dusty, scratchy blackboard—and presented my thoughts about immortal civilizations and the consequences for Earth and SETI. The audience of mostly older scientists was attentive and full of great, challenging questions. Afterward, they showed me Shklovsky’s modest, cozy, book-lined office, which has been preserved, shrinelike. The walls and shelves were unchanged in the intervening twenty-two years since his death, and it felt intimate, like slipping into his lively, luminous mind. They invited me to sit in the great man’s chair. From his neat wooden desk, I gazed out through a dense tangle of poplar branches nodding rhythmically against a darkening fall sky. I imagined Shklovsky looking out on these same tall trees while writing his timeless Un
iverse, Life, Mind, which grew into his classic collaboration with Sagan. On this space race anniversary, I felt the presence of futures past, the rushing ephemera of our lives against the patience of the cosmos. Looking up, I noticed a photograph taped to a glass cabinet filled with scientific reports: an eleven-by-fourteen glossy author photograph, slightly yellowed at the edges, of a radiantly smiling and handsome Carl Sagan.
Alexander Zaitsev (left) with the author outside the Moscow youth center, where teens worked on a message from Earth.
Sagan smiling down over Shklovsky’s desk (Sternberg Institute, Moscow, October 2007).
As Shklovsky and Sagan stated in the early 1960s, and SETI has accepted ever since, our first and most obvious role is to listen, not transmit. The rationale for this did not stem originally from concerns about ethics or existential risk. It was more about knowing our station in life. As Seth Shostak puts it, “We’ve had radio for a hundred years. They’ve had it for at least a thousand years. Let them do the heavy lifting.”
Zaitsev, however, believes that broadcasting to the stars is a good idea. The way he describes it, there is almost a moral imperative to transmit. At least, he feels, there is a logical necessity: if every civilization in the galaxy is listening but not sending, then there is no chance of success. He gave me a thick stack of papers he’d published on the rationale for METI. In one of them, he stated that “such an unselfish activity is natural for a developed civilization.”
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