One evening last year, when his newborn daughter was small enough to hold with one arm, René Heller reached for a book to occupy his mind while he rocked her to sleep. Heller, an astrophysicist at the Max Planck Institute for Solar System Research in Göttingen, Germany, picked up Is Anyone Out There? The Scientific Search for Extraterrestrial Intelligence.
The book is co-authored by Frank Drake, the renowned astrophysicist who came up with an equation to estimate the number of potential alien civilizations in the Milky Way. In it, Drake describes a fake alien transmission he composed in 1960, a series of ones and zeroes that encoded an image, and shared with his contemporaries in the field. Only one person eventually decoded it: a young electrical engineer from New York who had seen Drake’s message in a magazine for amateur code crackers.
Huh, Heller thought. “Why not come up with a modern version?”
So on April 26, 2016, an alien transmission appeared on Twitter. Heller posted a sequence of about 2 million zeroes and ones, binary digits meant to signify radio pulses coming from a pretend civilization 50 light-years from Earth. Radio signals have been considered an efficient means of interstellar communications since the 1960s, when the field of the search for extraterrestrial life, or SETI, was getting off the ground. Unlike other types of electromagnetic radiation, radio waves can pass through gas and dust over large distances of space without being absorbed or interrupted.
In this sequence Heller encoded information about these aliens, like their height, average lifespan, and the nature of their home star system and communication capabilities. He even included a hidden image of a slender, gray creature with long arms and an egg-shaped head. To get to this information, code crackers had to figure out what to do with a bunch of ones and zeroes, which span seven pages in your average text-editing program. Heller gave them about six weeks.
The first correct response appeared in his inbox the next day. Over the next several weeks, Heller received more than 300 replies to his call, including the right answer, the wrong answer, questions, pleas for hints, and even a few insults. (“This is one trait of the internet,” he said dryly. “You put out something and people just send an email to you and insult you.”) A spoiler showed up on Reddit. When the window for submissions closed, Heller had 66 correct responses from individuals or teams.
Most of the responses came from North America’s East Coast and Western Europe—not surprising, Heller says, considering the call was in English. They included scientists, software engineers, and, among others, two high-school students. Half had a bachelor’s or doctorate degree in mostly scientific fields. The vast majority were men.
To find the secret image, the string of ones and zeroes should be treated as black and white pixels and arranged in a certain way, so that the alien pops into view. You can do it yourself: copy and paste the sequence, found here, into a text editor, adjust the width of the window so that the first line is made up entirely of ones, and the first zero starts the second line. Zoom way out, and start scrolling down. Soon enough, the ghostly shape of a two-dimensional lanky alien should blur into existence before your eyes.
Deciphering the non-visual information, like numbers meant to signify the imaginary aliens’ height and lifespan, is a little trickier, and involves a good deal of math, an understanding of how binary code works, and knowledge of values known as cosmological constants. (For all the details, check out Heller’s paper on the experiment here).
Heller said the enthusiastic response to the call surprised him: “I would have expected maybe five or 10 of my Twitter followers, who are mostly astrophysicists or people who are interested in astrophysics, to maybe respond.”
The decoders of a real alien message from afar, should one ever reach Earth, may not necessarily need to be astrophysicists or linguists, as science fiction has shown. They could be computer programmers or hackers. Heller’s digital experiment illustrates the advantage of applying people from a number of disciplines to a single problem. The method is also in line with one of the mission statements of SETI. “A confirmed detection of extraterrestrial intelligence should be disseminated promptly, openly, and widely through scientific channels and public media,” states the SETI Institute in its protocol for what should happen when intelligent life is detected. A few months ago, when telescopes observed mysterious dimming in the brightness of a distant star—which some say could be caused by some kind of alien structure blocking the light—scientists live-tweeted about it.
Drake, the original sender of fake alien messages, wrote in his book in 1992 that his experiment taught him that amateur code crackers should be involved in the decryption of extraterrestrial messages. That was before the world wide web revolutionized the way we communicate. Is it a good idea to let anyone with an internet access the chance to decode an alien transmission?
“Obviously there is a really giant pool of creativity out there. It’s a very good environment for collaboration,” Heller said. “Consider those internet forums, where people meet and discuss their incremental approach toward a solution.”
But the internet is as capable of sowing trouble as it is cooperation. “On the other hand, there are also weird people and there would certainly be conspiracy theories or people throwing around garbage or ‘fake news,’” he said.
The announcement of an alien transmission could also, naturally, trigger some Orson Welles-style panic. “It could funnel or focus the fears of people,” Heller said. “If you would throw out this image of our alien friend—I find it funny, and in this context it certainly has a funny meaning. But if this would be a real image of some alien creature, it might also be very creepy. It might disturb people if we, as scientists, wouldn’t prepare it or announce it in an optimal way.”
If extraterrestrial intelligent life speaks in radio waves, humanity has the technology to hear it. Telescopes in California, West Virginia, and Puerto Rico survey the night sky for radio signals from beyond Earth. The Square Kilometer Array, a proposed telescope that may begin construction next year, will be powerful enough to detect radio signals originating billions of light-years away, as far back as the early universe.
Humans haven’t heard anything promising, but they’ve been broadcasting. In 1975, Drake, with help from Carl Sagan and others in the field, used radio waves to transmit a message to a star cluster 25,000 light-years away. The cosmic communiqué, known as the Arecibo message, carried information about numerical figures, the makeup of DNA, a figure of a human, and a graphic of the solar system. Several messages have been sent since, ranging in content from basic information to “Across the Universe” by The Beatles, even as the scientific community debates whether humans should be sending messages at all. There are certain scenarios to consider: Whoever hears our call could swing by and teach us some time-bending language skills, or they could zap us out of existence.
For now, the decryption of a fake alien message is thrilling enough. When Heller walked me through the zooming in and scrolling down and I saw the alien pop against a sea of ones and zeroes, I practically yelped in excitement. “You’ve just gone through this moment when you realized the content of an—at least fake—SETI message,” Heller said. “Isn’t this nice?”