Nestled in an arid Northern California valley ringed by volcanic mountains, the Hat Creek Radio Observatory is home to 42 six-meter-wide parabolic antennas. Inside the observatory’s visitor center, which is open Thursdays and Fridays from 9 a.m. to 3 p.m., is a small, freestanding wooden case that contains, among other items, an Energizer battery, a COVID rapid-test cassette, a blue origami crane, and a lump of coal.
The antenna dishes are there to pick up radio signals from alien civilizations. The case and its contents are there to help make sure our own civilization doesn’t self-destruct.
Both are projects of the SETI Institute, a research nonprofit founded in 1984 whose acronym stands for “search for extraterrestrial intelligence.” The antennas, collectively known as the Allen Telescope Array, represent what the institute is best known for: keeping an ear out for signals that might indicate intelligent life beyond Earth.
The wooden case and its contents seem modest compared to the antennas, but they represent something arguably more ambitious. They’re part of the Library of the Great Silence, an artistic project created by SETI artist-in-residence Jonathon Keats. Its stated aim: to “invite beings throughout the universe to collaboratively research planetary futures.”
Instead of distributing books, the library collects objects associated with transformational moments in the history of human civilization. Temporary libraries that Keats has set up at other sites have included a prehistoric hand axe, coins of various currencies, a plastic water bottle, a package of antibiotic tablets, a radiation dosimeter, and fragments of trinitite (the glassy mineral produced by the 1945 Trinity nuclear bomb test). Keats has designed a system that enables visitors to work together, without relying on words or other cultural assumptions, to determine what each object means.
The odds of aliens stopping by the Hat Creek library are vanishingly small, especially given the visitor center’s limited operating hours.
Eventually, like the Little Free Libraries you may have seen around your neighborhood, Keats envisions a network of sites where people — on this planet and beyond — can contribute their own artifacts.
Keats knows that the odds of aliens stopping by the Hat Creek library are vanishingly small, especially given the visitor center’s limited operating hours. But even if E.T. never shows up, Keats encourages humans to participate, because it offers us a valuable opportunity to challenge our most fundamental preconceptions about ourselves.
For example, by thinking about how we could exchange ideas with alien beings whose perception of time is radically different from ours, we could become better at working with people from cultures with different temporal values, and we may develop the ability to think on longer time scales. These skills are crucial for addressing global existential threats like nuclear weapons and ecological collapse, says Keats. If humanity is going to stick around long enough to become part of a larger galactic community, we’d best start getting over ourselves.
Keats, who describes himself as an “experimental philosopher,” is known for building real-life thought experiments that take aim at human exceptionalism. These include a scholar-in-residence program for plasmodial slime molds at Hampshire College, sex toys for plants, and a series of paintings depicting the average shade of the universe, which a team of astrophysicists in 2002 determined to be a light beige.
By building projects that serve non-human perspectives – an astrophysics observatory for bacteria, a clock for pine trees, pornography for God – he hopes to disrupt his viewers’ perceptual frame, showing them the world from a new angle that might spark different ideas about intractable problems — particularly environmental ones.
“Part of why we’re in the trouble that we’re in is that we’re having a conversation with ourselves,” says Keats. “We’re leaving out beings who have deep knowledge of what’s going on.”
From things to words, and back again
Keats is not the first to consider the challenges of crafting messages that aliens could understand. One popular proposal in the 19th century involved turning Siberia into a billboard for Martians. The idea, first published in 1826 and attributed to the German scientist Carl Friedrich Gauss, suggested planting three vast squares of wheat arranged in a triangle, so that Earthlings could communicate the Pythagorean Theorem to the Red Planet.
In the 20th century, humanity began sending more self-centered messages to the stars.
In 1974, astronomers used the powerful Arecibo radio telescope in Puerto Rico to transmit simple images — a human stick figure, our solar system, a DNA molecule — to a star cluster about 21,000 light-years away. NASA’s two Voyager spacecraft, launched weeks apart in 1977, each contained a gold-plated copper phonograph record showcasing human life and the diversity of its cultures, including greetings in 55 languages and music from composers ranging from J.S. Bach to Chuck Berry. Both probes have now left our solar system.
It’s impossible to say for sure what aliens would make of humanity’s message in a bottle, but they might see us as rather self-absorbed: The record contains 90 minutes of humanity talking about itself without ever asking a question.
For Keats, the process of creating a shared language is better started with material objects. After all, if intelligent aliens exist, we don’t know if they can understand drawings or hear recordings. But there’s a good bet that an intelligent being can — in one way or another — perceive a physical thing.
“Making meaning, to me, is linking objects to concepts and manipulating those concepts,” says Keats.
In a sense, the Library of the Great Silence uses the reverse of a process that linguists use to reconstruct prehistoric languages. Adam Cooper, a linguistics professor at Northeastern University, does research to reconstruct Proto-Indo-European, an extinct language that’s the ancestor of nearly every language spoken in Europe, the northern Indian subcontinent, and most of the places in between. Proto-Indo-European is believed to have been spoken about 6.000 years ago by a population living in Eurasia.
Almost all we know of how the Proto-Indo-Europeans lived comes from analyzing known languages and finding common roots. By piecing together how they spoke, linguists also can shed light on how they thought.
“Kinship terms, body parts, numbers, terms for various parts of a house — these have all been reconstructed,” says Cooper. “Once you’ve reconstructed a vocabulary, you can get a sense of what their priorities were, what their environment was,” he says. “From there, you can start to make connections to archeological or anthropological findings.”
Cooper, who is not associated with the Library, doubts that it would work quite so well when applied to beings that originated on another world, with a completely different physical environment. “If I’m being realistic about it, the lack of shared understanding would be a hurdle,” he says. “But there’s value here as an exercise to bring to life preconceived notions that we might think are shared by others, but in reality, are our own.”
A befriending library
In the absence of alien contact, Keats has been testing his process on humans. Before opening the terrestrial headquarters for his library at Hat Creek, he opened temporary branches in San Francisco, Italy, Hungary, and Germany. (He hopes to expand his library system to more locations, including satellite branches orbiting the Earth.)
Library visitors are presented with the objects without any descriptions — any labels appended to the objects would inevitably carry a pro-Earthling bias. They’re also given a set of interlocking wooden circles, cubes, and arrangements of square dowels that behave as logic gates, which can be used to establish logical relationships like “and” and “or.” Visitors create Venn diagrams that describe the commonalities between the objects, then mark the wooden cubes to assign symbols to those commonalities. The logic gates help them explore what happens when different symbols are paired together.
For instance, visitors might group a lump of coal and a water bottle together under the concept of fossil fuels, or the coal and a battery under the concept of energy storage. Grouping the coal, the battery, and the water bottle together might yield a new concept, perhaps one that unites the concepts of energy and waste.
Keats says the process can generate new perspectives on how civilizations transform, grow in complexity, and overextend themselves — and, perhaps, new concepts that don’t yet have names.
Seth Shostak, who has served as the SETI Institute’s senior astronomer since 2001, remains agnostic over whether Keats’s system would appeal to beings that share none of our evolutionary history. “He’s designed it in a way that would certainly be comprehensible to a tribe in New Guinea that has never contacted anyone else,” he says, “but I’m not sure if aliens would be able to understand it.”
Shostak emphasizes that the SETI Institute’s mission is to listen, and that it isn’t in the business of transmitting messages to the stars. “What we say probably doesn’t make a bit of difference to the aliens,” he says.
The dismal silence
The “Great Silence” in the library’s name refers to the search for alien intelligence’s central enigma: Once a civilization develops the capacity for spaceflight, it would probably take a few million years for it to populate the entire Milky Way.
Millions of years sounds like a long time, but in a galaxy that’s been around for more than 13 billion years, it’s the blink of an eye. Even if the odds of a particular star system giving rise to a spacefaring civilization are as low as one in a billion, our planet should have been settled by aliens many dozens of times over. Sure, there’s still a chance in that scenario that our future overlords just haven’t yet gotten around to colonizing Earth yet, but shouldn’t we at least have heard from them? In the words of Enrico Fermi, the nuclear physicist who first framed this apparent contradiction some 70 years ago: “Where is everybody?”
Theorists have proposed a variety of responses to the so-called Fermi Paradox. Maybe not every being shares humanity’s enthusiasm for conquest. Or perhaps alien technology doesn’t incandesce electromagnetic radiation like ours does. Maybe aliens observed how we behave and concluded — not entirely without reason — that Earthlings are best avoided.
Or maybe everyone out there is doing what the SETI Institute does, which is to passively listen without broadcasting anything. Our region of the galaxy could be like a Zoom breakout where nobody wants to be the first to talk. Maybe the Great Silence is really just a Great Awkward Silence.
Shostak says it’s premature to conclude anything about alien civilizations, given how recently humanity’s search for them began. If someone in early 1400 had sailed 200 miles west from Spain and turned around, he says, “they would have concluded that there’s nothing out there.”
But eventually, anyone who ponders the Fermi Paradox long enough might end up raising a possibility that is as terrifying as it is plausible: As a species’ technological abilities rise, so do the odds of its self-destruction.
With humans so far, our ability to launch rockets into space developed hand-in-hand with our ability to launch missiles into cities. We’ve unleashed the energy stored in fossil fuels, which has unraveled the climatic conditions that gave rise to civilization.
“If there’s something that is self-annihilating in the trajectory of technological development, that’s something we really need to be thinking about,” Keats says.
So if alien visitors are on the way, humanity would probably do well to work on its cross-cultural communication skills. But if they aren’t, we should work on those skills anyway. Our very existence could depend on it.
“We can do real work as humans,” says Keats, “whether or not we are alone in the universe.”