The search for extraterrestrial intelligent life in the universe may sound like science fiction to some, but it’s been a legitimate and active part of astronomy research for decades. Now, some researchers want to take the next step, from looking for signs of life to sending out signals and telling any aliens out there: “Hey, we’re down here!”

This idea has drawn criticism from the likes of Stephen Hawking and launched a debate that will come to a head this year as a young organization rolls out its plan to craft a message to blast out to potential aliens some time in 2018. METI International, launched in 2015, is a nonprofit research group that plans to start messaging by the end of next year. Their name means “messaging extraterrestrial intelligence” (a play on SETI, the “search for extraterrestrial intelligence”).

“One of the big questions has been: is this dangerous, to be transmitting to extraterrestrials?” said Douglas Vakoch, the president of METI International. “Maybe they’re having a bad millennium and they’re feeling malevolent. But if that’s the case, they can come anyway.”

The main criticism that arises is how little we know about any potential life forms out there, and if they’re unfriendly, alerting them to our existence could be fatal. They might decide to attack our planet for resources, or eliminate our entire species just for fun. Or, if they’re like the heptapods in Arrival, just trying to help unite us.

“We have almost zero idea of whether aliens are likely to be dangerous,” wrote Mark Buchanan, a physicist, in an issue of Nature Physics last summer. “The single history of evolving biological life that we know of — here on Earth — carries a strong theme of violent conflict, perpetual battle for resources and the oppression of weaker groups by stronger ones.”

We’re not exactly an optimistic case study. But those in favor of reaching out, like Vakoch, believe if these unfriendly life forms are out there, and have the scientific advancement to travel to us, they would have already been able to find us: the Earth has been leaking radio waves for decades, which have reached the nearest 7,000 stars.

Vakoch has a PhD in psychology but has been grappling with the question of whether to try to communicate with intelligent life in the universe—and what to say if we do—since the late 90s with the SETI Institute. He told me part of the METI mission is to test out a challenge to the Fermi paradox—which questions why, if the universe is theoretically teeming with life, we still haven’t met any aliens.

One theory is that intelligent alien life surrounds us, but is keeping itself hidden from us plebeian life forms. The only way to get their attention would be to reach out first. (Fellow Star Trek fans will recognize this theory as fitting in nicely with the Prime Directive.)

It wouldn’t be the first time we’ve deliberately sent messages into space: NASA has done it, with its golden record on Voyager, plaques on Pioneer 10 & 11, and (for some reason) a Beatles song it beamed out in 2008. But the difference is that these messages were tangential to the real mission: great, if some aliens stumble across them, but they were not directed at a planet where we think life might exist. METI, by contrast, would be very deliberately sending messages to specific locations, such as Proxima B, an Earthlike planet in the habitable zone near our closest neighbor, Proxima Centauri. That message could travel to Proxima B in just over four years, meaning we could have a response (if there is indeed intelligent life there) just over eight years after sending the message.

But if you’re still siding with Stephen Hawking with this one and are worried it’s too risky, don’t panic yet. Vakoch told me METI will be hosting three important meetings this year to continue this debate. One meeting, in St. Louis in May, will specifically consider the potential risks and benefits of alerting other possible life forms to our existence, and may in fact convince the group to hold off on sending out messages.

“That’s possible,” Vakoch said. “We want to hear from people who do have concerns and we want to look for a method that will let us find common ground.”

And even if METI goes forward with its plan to send out a message in 2018, it will need either the permission of one of Earth’s existing large radio telescopes, or enough funding to build their own, so there’s no guarantee either will happen.

Whatever side of the debate you fall on, it’s pretty fascinating to see the different arguments unfold. The possibility of intelligent life in the universe is so real, it’s causing some of our greatest scientists to freak out over whether or not we want to find it.