Trying to find aliens by pinging only one star system is a long shot. But although the broadcast from Norway is unlikely to provoke a response by any Luytenians, you can be sure it will provoke plenty of Earthlings.

That’s because METI is controversial. To begin with, what do you say to someone you’ve never met, and who’s a member of a different species? This has been batted about at more than a few conferences, and much of the conversation centers on whether we should show our bad side. Do we tell aliens that we engage in war, threaten our environment, and chow down on other critters? Personally, I don’t get too exercised about these discussions. Such concerns — while of great importance to us — are likely to be mere curiosities to the aliens.

But the aspect of METI that really inflames people (including some in the SETI community and even celebrated physicist Stephen Hawking) is the possibility that sending signals skyward may expose us to an existential danger. Suppose Luytenians do exist, and they’re unfriendly. If we tip our hand with a broadcast — no matter what its content — they might respond with a fleet of interstellar missiles to take us out. Bummer.

Frankly, it’s hard to think of any credible reason why aliens would do this. But why take the chance? My answer is twofold. To begin with, we’ve been broadcasting into space with high-powered transmitters (radar and TV) for more than a half-century now. Sure, those signals aren’t easy to detect out there in space — at least for someone with our level of technology. But for a society a century or two ahead of us, it would be trivial. And if the aliens are not at least that advanced, they simply won’t have those interstellar missiles.

So that’s point one, and it’s a doozy. Our hand has already been tipped.

But there’s something else, often lost in the discussion. Limiting strong transmissions skyward will straitjacket our descendants, not just in their efforts to do active SETI but for many other projects that might require beamed radio signals. If we want to map the outer regions of our solar system (to locate errant comets), we’ll need to use radars that are much more powerful than the ones we have today. If we envision having interstellar probes, signaling will be needed to keep in touch.

Let’s face it, it’s impossible to know what our great-great-grandchildren will find interesting or worthwhile to do. But telling them to never, ever aim a transmitter skyward is akin to telling them to never colonize Mars because, after all, there may be some indigenous microbes under the soil and it’s their planet.

Personally, I hope the Luytenians get in touch.

Read more: https://www.nbcnews.com/mach/science/we-just-beamed-signal-space-aliens-was-bad-idea-ncna822446