The scientists at Arecibo Observatory, a gigantic radio telescope in Puerto Rico, are some of the smartest astronomers and physicists in the world. But they need help with their next big project — and for that, they’re turning to kids.

In 1974, scientists used the 1,000-foot-wide telescope to send a carefully crafted radio broadcast into outer space, a message of zeros and ones meant to alert aliens to our existence.

It was humanity’s first interstellar message intended to be picked up by aliens. We haven’t heard back from E.T. yet. But in honor of the 45th anniversary of that transmission, the researchers at the observatory are pondering how to design a follow-up dispatch. Rather than asking their fellow experts, they’ve launched a global contest inviting youth — from kindergarteners to 16-year-olds — to create the New Arecibo Message.

The grand prize? A chance to have your message broadcast into the stars, and to potentially become the first human being ever to communicate with aliens.

I asked Alessandra Abe Pacini, a researcher at Arecibo who helped generate the idea for the contest, why kids are the best people for the job. “Sometimes the scientists are so focused on their topics and they can see stuff very deep but they cannot see very broad,” she said. “Students know a little bit about everything, so they can see the big picture better. For sure they can design a message that is actually much more important.”

But designing messages to aliens is a tricky business, on multiple levels. How do you write a missive that an alien intelligence will be able to understand? Should you avoid including sensitive information about humanity, in case that emboldens aliens to come to our planet and annihilate our species? Should you avoid transmitting messages into outer space altogether, because even just alerting aliens to our existence is too risky?

These questions are at the heart of a long-running, and sometimes very heated, debate among scientists. There’s no consensus about any of them, or even about the meta-question of who gets to decide on the answers.

One thing is clear, though: The stakes are extremely high. As scientists like the late Stephen Hawking and technologists like Elon Musk have warned, communicating with extraterrestrials could pose a catastrophic risk to humanity. In fact, if we send out a message and it’s received by less-than-friendly aliens, that could pose an existential threat not only to the human species but to every species on Earth.

The original Arecibo Message

When space scientists wanted to celebrate a huge upgrade that had been made to the Arecibo Observatory in 1974, two of their greatest minds stepped up to draft a memo to aliens. It would be broadcast from the telescope during a public ceremony. Frank Drake, who came up with the famous “Drake Equation” for estimating the odds that intelligent life exists in our galaxy, crafted the message with help from Carl Sagan, the astronomer and popular science writer who penned Contact and popularized the Search for Extraterrestrial Intelligence (SETI) organization.

Written in binary code — a series of ones and zeros — the message was designed with the hope of being intelligible to any aliens who might be listening. It sought to give them some basic information about us, like the position of Earth in our solar system, the size of the human population, the shape of the human body, and the double helix structure of DNA. When you look at the message in pictogram form, you can see all these components and more.

But this interstellar postcard was directed at M13, a globular star cluster 25,000 light years away, which may help explain why we haven’t heard back yet — it’ll take 25,000 years for the message to get there and the same amount of time for any reply to get back to us. The scientists chose that destination partly because the star cluster was big and relatively close, and partly just because it was within the telescope’s declination range (the part of the sky it can target) at the time of the ceremony.

In other words, the scientists weren’t really aiming to communicate with an alien civilization in their lifetimes so much as they were trying to publicly showcase the fact that their telescope could now do something incredible: For nearly three minutes, it sent a cosmic hello from humanity into the sky, as the audience assembled on site was moved to tears.

Why do we need a new broadcast?

Unfortunately, some of the information in the original message is now outdated or just plain wrong. For example, it gave the size of the human population as nearly 4.3 billion, but now it’s more like 7.7 billion. And the information it provided about the nucleotides in DNA has since been shown to be false.

Back in 1974, we hadn’t even found any exoplanets (planets outside our solar system). The first of them was discovered at Arecibo in 1992. Today we know there are actually lots of exoplanets in the so-called “Goldilocks zone” — not too hot, not too cold, but just right for the evolution of life.

But this global contest isn’t just about correcting old errors. It’s about getting kids interested in space science and fostering the sense that every earthling in every country around the world has a stake in this project. Teams composed of up to ten students plus one mentor must register soon — by March 20 — and they’re supposed to be international and multi-disciplinary. In fact, the more diverse your team is, the more points it gets. The contest guidelines recommend using social media to find possible teammates in other countries or regions.

Researchers at Arecibo also want to make sure the world knows that despite the devastation Hurricane Maria brought to Puerto Rico in 2017, the observatory is up and running. The natural disaster harmed the telescope’s reflector dish, but that’s been repaired, although parts of a broken antenna were still strewn beside it when I visited in January. “We went through the hurricane, so people maybe think we are closed,” Abe Pacini told me. “We are trying to have a refresh.”

The researchers are also trying to refresh their own ideas about how humans can compose a message that aliens will be able to understand, a field of study known as exosemiotics. It’s possible the design of the original Arecibo Message was based on fundamentally flawed assumptions — for example, that aliens have vision and so will be able to see the pictogram. Kids, who often come at problems from a completely new perspective, may take the blinders off scientists.

Arecibo researchers aren’t yet entirely sure whether they’ll actually broadcast one of the competing teams’ designs into the sky — it depends on the quality of the proposals they receive. If they get a contest entry with an innovative plan for the content of the message as well as a practical plan for where to send it (the destination has to be within Arecibo’s declination range), “that will be crucial to make us fight for the transmission,” Abe Pacini said.

Just as crucial, she added, is a solid assessment of the “risks of exposure” inherent in messaging alien civilizations. One of the main goals of the contest is to educate youth about these risks. To win, they have to show that they’re aware of the concerns and include a proposal for addressing them. Abe Pacini emphasized that the question of whether any message should be sent into space at all is “very controversial,” adding: “Even here among the scientists at Arecibo, there is no consensus.”

So far, the Arecibo contest hasn’t inspired much opposition from scientists who are anti-transmission, partly because the contest guidelines are (perhaps intentionally) vague on the question of whether the winning message will actually be transmitted. But if the observatory does end up deciding to make a broadcast, it may become the target of considerable criticism — and not for the first time. After it broadcast the original Arecibo Message, some scientists expressed concern over the fact that a transmission had gone out without international consultation and buy-in. Even Drake, the man who designed the message, reportedly said he regrets transmitting it.

The case against broadcasting messages to aliens

In the decades since 1974, the critics of transmission have only grown more strident.

In 2010, Hawking famously articulated the risk of advertising our existence to E.T. when he said, “If aliens visit us, the outcome would be much as when Columbus landed in America, which didn’t turn out well for the Native Americans.” Scientists in Hawking’s camp often point out that aliens don’t need to have violent intentions to do us harm; they might just view us the way we view, say, ants — they’d step on us on the way to something else and think nothing of it.

Scientists who favor transmitting messages to aliens think that worry is unwarranted. Douglas Vakoch is an astrobiologist who spent many years at SETI before splitting off to found his own international organization, Messaging Extraterrestrial Intelligence (METI). Rather than just scanning the stars for signs of intelligent life, METI proactively seeks to make contact with aliens by transmitting radio signals from powerful telescopes.

“With respect to Hawking,” Vakoch told me, “the key point he was missing was that any civilization that could do us harm would already know we’re here from our accidental TV and radio leakage.” He was referring to the fact that we’ve long been unintentionally sending out messages that aliens could detect, because our TV shows and radio broadcasts constantly flow out from Earth into space.

But in that case, why bother sending a purposeful transmission like the New Arecibo Message?

“What would be different,” Vakoch said, “is that this would send a strong signal that this isn’t just us communicating with one another — it’s us attempting to make contact. And for some civilizations, maybe that’s the prerequisite” for entering into communication with earthlings. This idea is known as the Zoo Hypothesis, which suggests that extraterrestrials may be keeping an eye on our planet but are waiting for us to indicate that we want to be in contact and that we’re sophisticated enough to merit attention.

Those in the scientific community who oppose intentional broadcasts argue that Vokach is being misleading when he says aliens already know we’re here from our accidental leakage. Yes, our signals have been floating out into space for decades, but they’re weak and not directed at anything in particular. A purposeful transmission from a telescope like Arecibo would be much more powerful and targeted, so it would be easier for aliens to detect — the difference between a shout and a whisper.

David Brin, an astronomer and science fiction author, is one of the most vocal critics of METI’s approach. “Even if E.T. already knows we’re here,” he told me, “why do these METI guys want to multiply our visibility, literally by a factor of 10 million?”

Statistically, an alien civilization capable of detecting and responding to our signals is very likely to be older and more technologically advanced than we are. We’ve only been transmitting radio signals for about 100 years; the chances that they’d be picked up by a civilization that’s been using radio technology for less than a century are vanishingly tiny. The power differential makes seeking out the attention of alien civilizations a frightening prospect, because we can’t assume they’ll put their power to altruistic uses, Brin noted.

Even though he counts Vakoch as a friend, Brin had some harsh words for him. “The METI zealots dismiss their critics as quivering in fear of alien invaders,” he told me. “But most of us are much more concerned about the arrogance these zealots are displaying by presuming to speak for a civilization of 8 billion people without ever exposing their assumptions to normal debate and risk assessment.”

Vakoch sees it very differently. “We do want to avoid extreme risks, but this whole process of even thinking about risks biases us toward nonaction,” he said. “We have this natural tendency to think of doing something as being more risky. But sometimes doing something reduces risk, like having your kids vaccinated.”

He cited the availability heuristic, which says that when you’re trying to evaluate the risk of an unknown situation, the most vivid or available context that comes to mind colors your decision. “What’s a more vivid, available image than Hawking’s idea of marauding aliens coming to Earth and destroying us?” he said. “We’re naturally pulled to these images that are reinforced repeatedly by Hollywood blockbusters.”

Still, Brin says Vakoch shouldn’t get to make such a portentous decision on behalf of the entire planet. That goes for the Arecibo scientists, too. Even though Brin finds it laudable that they want to educate youth through a contest, he wouldn’t approve of them unilaterally deciding to transmit a winning entry. “It sounds as if they need a reminder of what they were told before,” he noted. “Their instrument is funded by the taxpayers.”

Who gets to make rules about what happens in space?

The more you think about the scale of the risk involved, the less obvious it becomes that any one class of people should have the power to decide about transmissions. As Kathryn Denning, an anthropologist who studies the ethical aspects of space exploration, put it in an interview with the New York Times, “Why should my opinion matter more than that of a 6-year-old girl in Namibia? We both have exactly the same amount at stake.”

For decades, the international community has been exploring the possibility of establishing a mechanism for global oversight when it comes to our engagement with outer space. But even if everyone were to agree that’s a good idea, the question of how to set it up and make it enforceable is incredibly complicated.

The 1967 Outer Space Treaty was an early effort in this vein. Ratified by dozens of countries and adopted by the United Nations against the backdrop of the Cold War, it laid out a framework for international space law. Among other things, it stipulated that the moon and other celestial bodies can only be used for peaceful purposes, and that states can’t store their nuclear weapons in space. The treaty suited its historical context, but it didn’t tackle the concerns people have nowadays about messaging an alien intelligence.

Another inflection point came in the late 1980s, when SETI scientists drafted a post-detection protocol, a list of best practices for what to do if and when we ever find aliens. One of its principles reads: “No response to a signal or other evidence of extraterrestrial intelligence should be sent until appropriate international consultations have taken place.” This protocol was put on file as a brief with the Outer Space Treaty at the UN, and it was endorsed by the International Academy of Astronautics and the International Institute for Space Law. But it has no regulatory force when it comes to those who actively send out messages à la METI.

In 2015, SETI researchers, Elon Musk, and others released a statement criticizing METI efforts. “We feel the decision whether or not to transmit must be based upon a worldwide consensus, and not a decision based upon the wishes of a few individuals with access to powerful communications equipment,” it said. “We strongly encourage vigorous international debate by a broadly representative body prior to engaging further in this activity.”

So far, though, there is still no “broadly representative body” regulating what messages can be sent into space or by whom. Vakoch told me he’s charging ahead with METI and that he aims to transmit a message later this year. There’s no law saying he can’t.

The transmission debate reflects our deepest hopes and fears

The controversy over transmissions isn’t reducible to a discussion about laws and regulations. Underlying it are gut-level feelings and questions that are deeply philosophical and, arguably, spiritual.

Vakoch, who in addition to his astrobiology background also has a PhD in psychology, thinks a lot about the psychological drives animating the projects of METI and SETI. “Whenever we approach the unknown it’s with a sense of both intense hope and fear,” he told me. “And I think there’s a real polarization when we think about the impact of discovering another civilization — it’s ‘Oh my god, this could lead to our annihilation!’ or ‘Oh my god, this could be our salvation! They may send us the Encyclopedia Galactica or a cure for cancer!’”

The second impulse was on clear display when I visited Arecibo last month. In the visitor center was a bulletin board where kids were invited to post messages they want to convey to aliens. Several of them were pleas for help. One child’s misspelled missive was especially poignant: “Earth is destroying it self. Help us! Please help! Send better knowledg.”

For Brin, all this has a clear theological valence. He likes to compare METI endeavors to prayer. “If you boil it down, what these guys are trying to do is send a signal beseeching sky beings for salvation from the doom that seems to threaten us,” he said. “That’s called prayer, and people have been doing it for many thousands of years.”

As I spoke to the various players involved in this heated debate, I had the sense we may be projecting our feelings onto the sky in another way. More than anything, our anxieties over interstellar communication seemed like a reflection of our anxieties about communicating with one another. Underneath the question of how to talk to alien minds is a question that’s much closer to home: how to make ourselves understood to other minds right here on Earth.

It reminded me of something Abe Pacini told me. “When you think about communicating with extraterrestrial civilizations, you immediately think about the fundamental questions of life: Are we alone? Why only us?” she said. “If you look up there, you are actually looking inside yourself, and you necessarily need to consider big questions about yourself.”

Sign up for the Future Perfect newsletter. Twice a week, you’ll get a roundup of ideas and solutions for tackling our biggest challenges: improving public health, decreasing human and animal suffering, easing catastrophic risks, and — to put it simply — getting better at doing good.