This article originally appeared on Motherboard.
Released in US theaters just a week ago, Arrival is quickly shaping up to be the science fiction movie of the year, a turn of events that almost no one—including the author himself—would've guessed based on its premise.
The story follows linguist Louise Banks (played by Amy Adams) and theoretical physicist Ian Donnelly (played by Jeremy Renner) as they attempt to communicate with a pair of extraterrestrials whose spacecraft has just landed in Montana. For most of us, Arrival was just another entertaining alien flick, but for a handful of Search for Extraterrestrial Intelligence (SETI) researchers who are actually tasked with figuring out how to communicate with extraterrestrials, the film felt more like a documentary than a drama.
"I am so envious of Louise Banks because she gets to have a face to face with ET," Messaging Extraterrestrial Intelligence (METI) International president Douglas Vakoch told Motherboard. "But in the scenarios that SETI and METI folks deal with there's no possibility of that. Our idea of a snappy exchange with extraterrestrials is a decade—and that only works if the nearest star is populated."
Prior to becoming the president of the recently founded METI International, which focuses on the controversial science of sending messages into space, Vakoch was the Director of Interstellar Message Composition at the SETI Institute in California. For a large part of his career, he has been trying to figure out how to communicate with an intelligent extraterrestrial species when you don't even know the first thing about them and a message takes decades to reach its destination.
Although Amy Adams' character makes it look easy in Arrival, the real art and science of talking to aliens—known as astrolinguistics or METI—is much more complicated, involving a healthy mix of linguistics, mathematics, physics, and imagination.
In Arrival, Renner's character ribs Adams for her approach to communicating with the aliens, telling her that she does linguistics "like a mathematician." Although this throwaway comment was made in jest, in real life that's more or less how it's done. As Vakoch pointed out, one of the luxuries enjoyed by Adams in the film is that she is able to communicate in real time with the aliens. But for the METI researchers sending messages into the cosmos, they are expecting decades—if not centuries—to elapse between sending a message and receiving a response, which fundamentally changes the way they think about constructing a message.
In the first place, it means that a message sent into the cosmos needs to be incredibly robust and ideally entirely self-referential. Unlike Arrival, Earthlings don't have the ability to teach the recipients of their messages anything about it because the delay in communication is so long. So not only do METI researchers have to send the content of the message, but they also have to send instructions for how to read it, and these instructions must somehow be intelligible to the aliens as well.
What this means is that rather than trying to figure out how the structure of an alien's language might uniquely shape their worldview (the theoretical basis of Arrival known as linguistic relativism) and basing a message off of that, METI researchers go in the opposite direction.
"We're looking for a cosmic Rosetta stone," said Vakoch. "But the question is: What do us and the extraterrestrials both have in common?"
As you might expect, this question leads most METI researchers to languages rooted in mathematics and physics, which one would expect to be known to an alien civilization capable of mastering the technology to receive our message in the first place.
When a 20th century Dutch mathematician named Hans Freudenthal created LINCOS, the first language expressly designed for communicating with extraterrestrials, he used mathematical principles to discuss everything from the nature of time to what it means to love. In 2013, a Dutch mathematical astronomer named Alexander Ollongren created a second version of LINCOS, which communicates similar ideas couched in the language of symbolic logic and lambda calculus. In both of these instances, the lingua cosmica is self-contained and rooted in supposedly universal principles (mathematics and logic)—but it still might be unintelligible to an alien.
"Even if humans and extraterrestrials both have math and science, they're not necessarily interchangeable," said Vakoch. "Maybe science starts out at different places depending on the biology or particular needs of the organism. There is a subtle truth that Arrival points toward, and that is the way we construct and talk about the world may reflect something idiosyncratic about our species."
To illustrate his point, Vakoch cites the emergence of non-Euclidean geometry in the 19th century. For two millennia, Euclid's view of a flat universe reigned supreme and pivoted on his fifth postulate, which states that two parallel lines will never intersect. But when a handful of European geometers in the 1800s replaced this axiom with its opposite—that two parallel lines actually can intersect—they fundamentally changed our view of reality by making space curved instead of flat.
The important point is that both geometries are internally consistent and have been used for innumerable scientific and mathematical discoveries. So just because we're speaking the language of science or math to aliens doesn't necessarily mean we're talking about the same science and math.
With this in mind, Vakoch advocates for exploring dozens of different ways of trying to communicate with ET. He thinks that the idea of trying to create a self-contained message that can be delivered all at once is a product of the human desire to see a send and reply happen within one generation. If we abandon this idea and accept that interstellar communication is likely to happen over the course of centuries or millennia, it opens up radically new ways of attempting to establish communication with aliens.
In the half a century that elapsed between the first and second versions of LINCOS, there have been no shortage of ideas for how to talk to extraterrestrials. Some have relied on aural or visual components, such as the Voyager spacecraft which contained sound and images on a record. Likewise the first radio communication intended for aliens, known as the Arecibo message, was also an image which depicted pixelated humans and the Arecibo telescope. Unfortunately, these types of messages are banking on the idea that aliens will have aural and visual systems like us—but given that sight has independently evolved dozens of times on Earth alone, this idea might not be as farfetched as it seems.
Other common ideas take the form of massive data dumps or sending out computer programs that will be capable of being run by the aliens once they've got a basic grip on human coding paradigms. This was the idea behind CosmicOS, a computer program that would essentially use a role-playing game to teach aliens about Earth and that one time the entirety of Craigslist was sent into the cosmos (more of a publicity stunt than anything, but maybe aliens need a new divan?). Other strategies go back to hard science, like the RuBisCo Stars message which sent the DNA sequence for the protein used in plants for photosynthesis.
Whether any of these signals will ever reach or be intelligible to extraterrestrials is impossible to say, which is why Vakoch and his colleagues at METI International are focusing on exploring as many different message constructions as possible in the meantime. They hope to begin transmitting messages into the cosmos by the end of 2018, but for now the important thing is to have an open mind and active imagination, which for Vakoch is one of the main takeaways from Arrival.
"The thing I most liked about Arrival is that it captures the sort of openness to a new way of understanding the nature of reality that we need to be capable of to understand another civilization," said Vakoch. "That's what we hope for in SETI and METI: that over the course of decades or centuries we'll be able to come to understand how another civilization understands and talks about its world."