Astronomers seeking contact with extraterrestrial civilisations have typically relied on messages based on maths and science. They reason that alien engineers will surely know some fairly sophisticated physics. If not, ET probably won鈥檛 be able to create the radio transmitters and receivers that make interstellar communication possible.
But the actual messages humankind has sent into space have sometimes included quite different content. The Voyager Golden Record, launched by NASA in 1977, included the audio greeting: 鈥淗ello from the children of planet Earth鈥�. No one imagined such cosmic tweets would be meaningful to extraterrestrials 鈥� only to the humans sending them. But maybe our language would not be totally alien to them.
METI International, the research organisation I head, began its namesake activity of messaging extraterrestrial intelligence in late 2017. We targeted an exoplanet orbiting Luyten鈥檚 star, a mere 12.4 light years from our solar system, sending a mathematical and scientific primer. On 26 May, in preparation for our next round of interstellar missives, we held a day-long workshop at the International Space Development Conference in Los Angeles. Our goal: to create more-intelligible messages by examining how humans talk with one another.
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Noam Chomsky, the father of modern linguistics, has said for decades that if a Martian visited Earth, it would think all humans speak the same language. To this alien eavesdropper, the differences between our diverse languages would seem like mere dialects of a single tongue, because our natural languages are so similar to one another. Chomsky argues that a universal grammar underpins all human languages. Such superficially distinct languages as Mandarin and Swahili differ only in their surface features, he says, while being united by hidden commonalities.
Alien grammar
Might universal grammar be universal throughout the galaxy? At METI鈥檚 鈥淟anguage in the Cosmos鈥� workshop, University of Cambridge linguist Ian Roberts, with Jeffrey Watumull and Chomsky, argued that alien languages may share some of the features of universal grammar. For instance, all languages on Earth combine individual words , which is repeated, over and over, to form complex sentences. From a finite number of words, we can churn out a huge number of unique sentences 鈥� a hallmark of language and one that separates it from the more limited outputs of non-human animal communication on Earth. These two steps of 鈥渃ombine and repeat鈥� might be found in extraterrestrial languages as well, Roberts and colleagues suggest.
As we plan future transmissions into space, do we need a different way to start our messages than we have used in the past? Should we replace the string of prime numbers featured in the movie Contact with the collected works of Shakespeare?
Read more: Exolanguage: do you speak alien?
Probably not. Instead, it might make more sense to focus on what mathematics and language have in common.
The linguistic process of merge has a striking similarity to basic arithmetic. The structure of addition is eerily reminiscent of the simplest of sentences, in which we combine nouns like 鈥渁liens鈥� and verbs like 鈥渞eply鈥� to describe the hoped outcome of our own transmission projects: 鈥淎liens reply鈥�. That shouldn鈥檛 be such a surprise. The same brains that make sure we combine plural nouns like 鈥渁liens鈥� with plural verbs like 鈥渞eply鈥� to form grammatically correct sentences also let us do mathematics.
In our next messages, METI will draw on some of the cognitive processes that undergird such seemingly different human creations as mathematics and language. Aliens may not know about partial derivatives or the past perfect subjunctive 鈥� at least not in the forms we are familiar with. If we start with the basics like merge and repeat, however, then build step by step to more complex descriptions, extraterrestrials may just be able to follow us. The full depth of multivariable calculus can wait until later.
Whatever the specific starting point of our messages to the stars, let鈥檚 remember that we are new to this game. We have had the radio technology that enables interstellar communication for less than a century 鈥� a blink of the eye in a universe that is nearly 14 billion years old. As infants in the cosmos, we should begin with baby steps: a few key concepts that make communication possible in the first place.
