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What Happens If E.T. Phones Us?

Four light years — more than 24 trillion miles — from our home planet there is a world orbiting a small, red star called Proxima Centauri. No human eyes have ever seen it. The scientists who announced its discovery Wednesday are pretty sure it exists because they can see the way the star wobbles under the influence of gravity every time the probably-a-planet passes close by.

Astronomers have confirmed the existence of 3,375 exoplanets outside our solar system, and 297 of those are potentially habitable. But “Proxima Centauri b,” as this new one is known, is special. Not only is it tantalizingly close (at least in terms of space distances), it’s also part of a star system that has long played an outsized role in our spacefaring fantasies. That little shiver you feel is your brain hoping that science fiction might, just might, become science fact.

And that made us wonder what might happen if, by some strange luck, Proxima Centauri b were to turn out to harbor signs of intelligent life. Who do scientists tell first? Who decides how we earthlings respond? How does one have a close encounter of the bureaucratic kind?

These are not totally ludicrous questions. Both NASA and the European Space Agency have planetary protection offices that deal directly with the possibility of less-than-intelligent life in space. These groups design and manage protocols that keep Earth microbes from hitching a ride to other planets — and reduce the risk of bringing any microbial E.T.s back here. The U.S. even has laws banning the collection of living things in space.

Actually finding intelligent life is probably less likely than infesting another planet with our own germs, but the people who search for that life do have a plan for what to do if they succeed. “When it comes to SETI, yes, there are protocols,” said Seth Shostak, senior astronomer with the SETI Institute, the nonprofit research center that manages the search for extraterrestrial intelligence. Formally adopted by the SETI Permanent Study Group of the International Academy of Astronautics in 2010, the document laying out those protocols has a big, fancy, official-sounding title: “Declaration of Principles Concerning the Conduct of the Search for Extraterrestrial Intelligence.” But the plan it outlines for what to do if SETI is ever successful boils down to a pretty simple set of rules, Shostak told me. “If you think you’ve found a signal, check it out. Secondly, you let everybody know. And third, you don’t broadcast any reply without some sort of international agreement that it’s OK to do so.”

The document also refers to a Post-Detection Task Group that can meet up and provide guidance to the public in the event that somebody does have to decide what to do about Proxima Centaurians. But the plan isn’t binding, and Shostak said no other organization or government has a written plan of action or rules to follow.

Michael Endl, a University of Texas at Austin astronomer whose graduate work on planetary detection formed the basis of the study that found Proxima Centauri b, agreed. If it was a one-time signal — a burst of contact like a flashlight winking on and then off in your neighbor’s window — the best thing to do would be to go through the routine scientific publication system. Write up the event, find a journal that will publish it, go through peer review — no different from how the discovery of Proxima Centauri b was announced. If the signal is constant, though — as if we tapped into an alien radio station — Endl said it might be published immediately in the Central Bureau for Astronomical Telegrams, a publication meant to alert astronomers quickly to the existence of constant but short-lived phenomena, such as supernovae.

But whether the plan is painstakingly detailed or ho-hum simple, Shostak thinks it’s likely to break down in an actual E.T. event. That’s because the similar protocols SETI operated under before the 2010 Declaration proved to be of almost no use back in 1997, when scientists thought — for about a day — that they really had picked up an alien signal. While they were still working on confirming that the signal was coming from extraterrestrials, Shostak started to receive calls from journalists who had heard something was up. “And I’m not gonna lie to The New York Times and say there’s no signal,” he said.

Spoiler: The 1997 signal turned out to be from a NASA solar research satellite. But if Step 1 and Step 2 could get turned around so quickly even back then, Shostak said, there’s no hope that if a signal were detected today you’d be able to confirm it first and then announce it. Not in the age of social media.

Of course, all this depends on there being extraterrestrial life to find. SETI has already looked — and found nothing — in Proxima Centauri b’s star system, Shostak told me. It was only a limited scan, though, and nobody knew at the time that there was a planet there to focus on. “I fully expect that within a couple weeks or a month you’ll hear about new observations,” he said.

Maggie Koerth-Baker is a senior science writer for FiveThirtyEight.

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