by Daniel Oberhaus
MIT Press, 2019
hardcover, 264 pp.
Often in science fiction the difficulties of communications between two alien species is minimized: think, for example, of Star Trek’s universal communicator or Han Solo and Greedo speaking in their own languages in the Mos Eisely cantina yet understanding each other (but good luck figuring out the meaning of Greedo’s final “maclunkey” in the latest re-edit of that scene.) Less often do the challenges of such communication become a major issue in a story, as in the movie Arrival.
But the difficulties of communicating with the heptapods in Arrival may be trivial to any effort to communicate with extraterrestrial civilizations. There have been, over the decades, a handful of deliberate efforts to send messages to other star systems, now known as messaging extraterrestrial intelligence, or METI (contrasting it with passive listening efforts known as the search for extraterrestrial intelligence, or SETI.) But is it realistic that any of those messages, if indeed intercepted by an extraterrestrial civilization, could be properly decoded and understood?
That’s the issue that science journalist Daniel Oberhaus grapples with in Extraterrestrial Languages. Sending a message in the blind to an unknown civilization is more complex than transmitting something like, “Greetings from Earth.” Crafting a message requires deep thinking about everything from linguistics to logic: assumptions we make about language, thought, and even mathematics might not be relevant to another civilization that developed differently.
There have been only a few deliberate METI projects, most famously the signal broadcast from Arecibo in 1974 towards a stellar cluster 25,000 light-years away. METI got something of a rebirth in 1999 with an effort called Cosmic Call that went to great lengths to craft messages transmitted to stars dozens of light-years away: that initial transmission, Oberhaus argues, resulted in “reigniting interest in interstellar communications” with a number of follow-on transmissions, some serious and others just publicity stunts. (The only deliberate transmission between the Arecibo and Cosmic Call messages, he writes, was in 1986, when an artist used MIT’s Millstone Radar “to send the sounds of vaginal contractions into space”; the transmission was stopped after a few minutes by an Air Force officer.) But even the Cosmic Call messages are more than 15 years from arriving at their target stars, so the earliest we could hope for a response is around 2070—assuming anyone is there to receive and decode the message.
METI, then, is something of an academic exercise: we don’t know if there’s anyone out there to receive a message, or what kind of message any civilization would be able to decode, and any response would likely take generations. Some have also worried, as far back as the Arecibo message, that such transmissions might be dangerous, alerting hostile civilizations to our presence. So why do it? Oberhaus argues such messages can be valuable in and of themselves: “Each message, regardless of whether it is broadcast, is like a mirror that reflects the spirit of the age that crafted it.”
Extraterrestrial Languages can itself be at times an academic exercise: Oberhaus dives deep into topics from linguistics to logic, challenging the reader to keep up. For example, he mentions several times the use of “lambda calculus” in communications schemes, but doesn’t give a succinct definition of it in the main text (he does go into much greater detail in an appendix.) This book is really for those interested in METI or SETI, or those with backgrounds in related field curious about how it might be applied here. And, as he notes, “if everyone in the galaxy is listening and no one is broadcasting then contact will never occur at all.”
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