Now and again scientists think of interesting ways to use our space missions in contexts for which they were not designed. I’m thinking, for example, of the ‘pale blue dot’ image snapped by Voyager 1 in 1990, an iconic view that forcibly speaks to the immensity of the universe and the smallness of the place we inhabit. Voyager’s cameras, we might recall, were added only after a debate among mission designers, some of whom argued that the mission could proceed without any cameras aboard.
Fortunately, the camera advocates won, with results we’re all familiar with. Now we have a project out of The SETI Institute that would use a European Space Agency mission in a novel way, one that also challenges our thinking about our place in the cosmos. Daniela de Paulis, who serves as artist in residence at the institute, is working across numerous disciplines with researchers involved in SETI and astronautics to create A Sign in Space, the creation of an ‘extraterrestrial’ message. This is not a message beamed to another star, but a message beamed back at us.
The plan is this: On May 24, 2023, tomorrow as I write this on the US east coast, ESA’s ExoMars Trace Gas Orbiter, in orbit around Mars, will transmit an encoded message to Earth that will act as a simulation of a message from another civilization. The message will be detected by the Allen Telescope Array (ATA) in California, the Green Bank Telescope (GBT) in West Virginia and the Medicina Radio Astronomical Observatory in Italy. The content of the message is known only to de Paulis and her team, and the public will be in on the attempt to decode and interpret it. The message will be sent at 1900 UTC on May 24 and discussed in a live stream event beginning at 1815 UTC online.
The signal should reach Earth some 16 minutes after transmission, hence the timing of the live stream event. This should be an enjoyable online gathering. According to The SETI Institute, the live stream, hosted by Franck Marchis and the Green Bank Observatory’s Victoria Catlett, will feature key team members – scientists, engineers, artists and more – and will include control rooms from the ATA, the GBT, and Medicina.
Daniela de Paulis points to the purpose of the project:
“Throughout history, humanity has searched for meaning in powerful and transformative phenomena. Receiving a message from an extraterrestrial civilization would be a profoundly transformational experience for all humankind. A Sign in Space offers the unprecedented opportunity to tangibly rehearse and prepare for this scenario through global collaboration, fostering an open-ended search for meaning across all cultures and disciplines.”
The data are to be stored in collaboration with Breakthrough Listen’s Open Data Archive and the storage network Filecoin, the idea being to make the signal available to anyone who wants to have a crack at decoding it. A Sign in Space offers a Discord server for discussion of the project, while findings may be submitted through a dedicated form on the project’s website. For a number of weeks after the signal transmission, the A Sign in Space team will host Zoom discussions on the issues involved in reception of an extraterrestrial signal, with the events listed here.
While it will be fun to try to decode the signal, in reality, a try alien signal will be very different. A simple example is from the movie “Contact” where the instructions to build an interstellar transport had to be read as a 3D image, not a 2D one. We have assumed binary transmission, with decimal numbers (based on our 5-fingered evolution) and prime number sides for 2D rectangles to display 2D images. How much of this is anthropomorphist thinking? The movie “Arrival” has a more inscrutable RT communication from the aliens. Lastly Lem’s “His Master’s Voice” has 2 teams that come up with 2 very different interpretations of a signal. On top of it, the signal must not be compressed in any way to redundancy.
To initiate any sort of communication, I have to wonder if it must be very simple and clearly artificial, e.g. transmitting something that cannot be interpreted as natural. However, as we expect ET is likely millions of years ahead of us, sending a signal to us may be as difficult as humanity sending a signal to remote ant colonies without knowing ants communicate via chemicals. IOW, we don’t live in a Star Trek universe with cultures being approximately at our level of technology.
Having said that, I will certainly play at decoding the signal. ;)
An infant/toddler playing with a pet or some toys may be unaware that some adults are watching in amusement until the adults call attention to themselves. And alien denizens of the universe may be able to achieve their ends with with such little disruption of matter and energy as to pass unnoticed.
If deciphering a presumed transmisson is desired, one should approach the the most qualified: the NSA (no sugar added?) or their equivalent in other countries.
It seems to me the simpler the signal the better…no primes, Fibonaccis, sequences of powers or anything else. And an analog pulse seems more workable than digital numbers. Just 1…2…3…a sequence of simple pulses,, either dot groups, or dashes of increasing length, separated by pauses of comparable length, perhaps ending at a relatively low number, then repeating again after a brief period of silence. How long the spacing is is pure guesswork, but it seems to me on the order of a second is reasonable. A creature evolving on an earthlike world will probably have to deal with a gravitational acceleration comparable to earth’s , so a second seems a good guess. But of course, that is pure speculation. It would not be too difficult to come up with a scenario for a creature that would yield quicker, or slower metabolisms and reaction times. Granted, we can deal comfortably with repetition rates much faster than we can perceive, but we have no idea how they think.
The point is, if you’re trying to make your presence known to aliens you know absolutely nothing about, then the signal needs be obviously artificial, and extremely simple. Anything beyond that is likely to not work at all.
The frequency should be chosen to be in the middle of the Waterhole, where the interstellar medium is transparent and where natural microwave background is lowest, and at a wavelength where no natural astrophysical process generates noise. Optical SETI makes technical sense for a data link, but not for a hailing beacon;, I doubt anyone is listening in that region of the spectrum, so its not likely anyone would want to transmit there either.
It might be tempting to encode more information in the signal, but that involves making assumptions about the psychology of the recipient.
Given that we can simultaneously receive and record a range of frequencies, we needn’t focus on a single frequency, just look for the signal[s] in the spectrum. We shouldn’t assume a single frequency either, as the signal may be spread across a number of frequencies for a number of reasons.
Simple signals of repeating number sequences can only be the equivalent of “hello”. A useful, informational signal will need to be more complex. I recommend Brian McConnell’s 2 CD posts as a primer. All Your Base Are Belong To Us! : Alien Computer Programs, Communicating With Aliens: Observables Versus Qualia.
Silverberg’s “Tower of Glass” (1970) has a plot device of a very simple signal of just a handful of small numbers that subtly change, but offer no meaning to the protagonist[s]. At least the signal looks artificial, but…
[I watched the “A Sign in Space” online interviews as the data was to be downloaded from EXOMars. Given the the participants in the message, and that there is a bet that not all of the message will be successfully decoded, I am fascinated to see what it might contain. It seems like it will be a very far cry from traditional SETI messages. Even the data will just be filtered raw SigMF voltage data, rather than binary.]
No one knows what the first signal will be like, of course, but I’ve always constrained my speculations by making the assumption that it will be designed so that it covers as large a volume of space as cheaply and efficiently as possible. This suggests one frequency, preferably one that can penetrate as far into the galaxy as possible and illuminate as many potential systems in as large a volume of space as possible.. This further suggests it will not be designed so that it will require as highly specialized equipment as possible. A loud noise, perhaps modulated slightly to guarantee its artifactual nature, will be the bare minimum.
Second, it will be cheap, both in energy terms and in design/maintenance of the transmitting equipment. Multi-frequency transmitters cannot be ruled out, but I suspect most active SETI programs will put all their resources into a highly optimized program; a lot of wattage in a frequency likely to go a long way and be easily detected over long distances. I’m still betting on a 21cm x a constant signal aimed in a rather broad beam into rich stellar condensations in the nearby galactic plane. The Milky Way appears roughly 10 degrees wide, that seems to me a reasonable footprint.
The chances of it being detected increase with the amount of time the active station will be on the air, I suspect these beacons will be very long programs. A transmitter operating for just a few years is not likely to be heard by anyone. But a thousand or million year program has a better chance of reaching a lot of listeners.
I may be mistaken, and there are good reasons for many other types of active SETI programs, but I suspect the “hello, we’re here” transmission will be the most likely to be detected. Once they know someone is listening, a targeted, information-dense signal makes more sense.
Still, SETI thinking today seems to be favoring the detection of non-communicative energy leakage, such as navigation beacons, radar beams, messages meant for someone else, or industrial noise. If that is the case, it is very difficult to predict just what we’re most likely to hear, or how long we’ll be in the beam.
The best way to send any electromagnetic radiation a long ways is to send it it in a tight focused beam, but this always presumes they’ll have a good reason to expect someone is there listening in their direction. I just can’t come up with a good reason why they should do so. Unless they’re fairly close to us, in space and time, they simply have no way of knowing we’re here.
Can someone if possible reproduce the new signal here? I went to the livestream event but it was very long and I am only starting to work my way through it. It would be interesting to see if it is in a form we can look at on here.
Agree. Using Python and the SigMF module, my computer just locked up trying to extract the data. In reality, any ET signal would be received, the data extracted by experts, and the processed signal posted for the interested to try to decode.
I hope that the principals understand that just trying to extract the data may block most people from even getting to step 1, a rather counterproductive approach, especially as there are a number of webinars to maintain interest in expanding the interpretation approach.