Science. Communication. Community.
“The limits of my language mean the limits of my world.” So how do we attempt communication beyond our world? With this blog’s recent shoutout in the newsletter of the American Astronomical Society, I thought I’d delve into a space science topic that intersects with my interest in sensory perception, communication, and linguistics: how do we phone E.T.?
The idea that there is a strong connection between our language and world view — and the thought or behavior that constrains us — was articulated in the above form by the philosopher Wittgenstein, and is also commonly known as the Sapir-Whorf hypothesis. With all the miscommunications and barriers arising from the multitude of languages on earth, successful extraterrestrial communication can start to seem like a pipe dream. Nonetheless, valiant attempts have been made to inform the aliens of our existence here on Earth, and those attempts have influenced fields like design and information visualization. Here is a short primer on a few endeavors to convey information in ways that are truly “universal.”
So, how do you compose an interstellar telegram? With alien recipients, the first rule is to make no assumptions. They most certainly won’t have arms or legs, heads or noses, eyes or ears. But if they are out there in the universe (and that is a big IF), it is likely they have developed ways to sense electromagnetic radiation or pressure, just like us. This means they could receive sounds or images. In this vein, some of the most well-known cosmic messages are the plaques on the Pioneer 10 and 11 spacecrafts launched in 1972-1973, and the Arecibo radio message that was broadcast in 1974. This brings us to a second important consideration: we can’t anthropocentrize anything in our message. Images of human beings or arrows (what is directionality in space?) will mean nothing to the Mork or Alf receiving the message. On the plus side, this means that any earthly prudishness in the message’s content can also be chucked out the window – though in the early 1970s, the genitals on the human figures depicted on the Pioneer plaque still had to be obscured.
Third, the universal language is science. In the film Contact — after one of humanity’s first video broadcasts was beamed back — the supposed aliens on Vega transmitted strings of prime numbers to Earth. A major component of the Pioneer plaque is the use of the hyperfine transition of hydrogen as a unit of measurement. This is used to tell the alien recipients not only the size of male and female images relative to the spacecraft, but also the distances within our solar system and beyond. The plaque gives the aliens a way to triangulate Earth using redundant galactic landmarks: the locations of 14 pulsars. Similar-looking Feynman diagrams have been lauded by information visualization guru Edward Tufte as the ultimate in beautiful and functional universal communication. On the lighter side, Tufte’s redesign of the Pioneer plaque cites magic as “cosmological entertainment” that is intelligible across cultural or planetary boundaries.
Pioneer’s companion spacecraft, Voyager, is disseminating the works of Beethoven and Chuck Berry and the voice of Jimmy Carter to the cosmos. The Golden Record LP aboard Voyager is already outdated technology just 35 years after its launch. It is meant to be played like a conventional record, with a stylus supplied on the spacecraft; hopefully the recipient can decode the instructions. The record also contains a video section of terrestrial images, the planets, DNA, and other everyday activities (“Licking, eating, and drinking”) that is sure to amuse the alien viewers.
We are still discovering new ways that our fellow animals sense the world. From the mantis shrimp with dodecachromatic vision (that’s at least 12 visual pigments in their eyes compared to the measly human three), to the dung beetles that navigate by the Milky Way to the fish with magnets in their noses, these sensory modalities could inspire new ways to think about how to send, and receive, information to and from the cosmic environment.
Even with all the cool unexplored methods of communication, humanity is now actually facing a problem: radio silence. For Earthbound civilizations, at least, there appears to have been a window of about 100 years during which were “visible” to the universe, via all the radio and television signals we were broadcasting. Now that terrestrial broadcast signals have largely been abandoned with the switch to digital, our window, at least in that part of the spectrum, may have closed. This in turn leads to the realization that we may not have been listening for ET’s call in the right way, using only radio telescopes.
Another possibility is that, like us, the aliens are increasingly “online,” disinterested in the outside world as they become more absorbed in their own civilization’s cultural offerings at the expense of space exploration. We may also (literally) be on different wavelengths: barriers to any kind of contact may not only exist in space-time distances, but also in cognitive speed. Their speech or understanding could be much faster or slower than ours, meaning that a meaningful message could go completely undetected simply because we couldn’t tell it apart from background noise.
Carl Sagan, Frank Drake, and others gave serious thought to the best practices for extraterrestrial communication, but since the 1970s it seems to have fallen out of vogue. After all, no one has even been to our only satellite, the Moon, in over 40 years. Luckily, the Mars rovers are keeping up the audio tradition, by playing music out on the Red Planet; the space station astronauts are also taking Top 40 tunes to the thermosphere. And now that the Martians have been treated to the warblings of the Black Eyed Peas, I’m sure they’ll think twice about attacking us.
UPDATE: Intelligent civilizations that could transmit radio signals are fewer than one in a million, according to a new pre-print out of Berkeley. See arXiv for the paper, and the news stories at the Daily Californian and Space.com.
Sagan & Drake (1975). The Search for Extraterrestrial Intelligence. Scientific American 232(5), 80-89.
Quill (2010). Can You Hear Me Now? Science News 177(9), 22-25.