A recent paper claiming that a comet was the source of SETI’s famous Wow! signal in 1977 has generated a barrage of scientific criticism. After writing about the controversy last week, I contacted several people with expertise in that scientific field, and their response was quite clear. Typical was this comment from Robert Dixon, director of Ohio State University’s SETI program: “Nobody in the field that I have heard from believes that comets emit enough hydrogen radiation to explain the Wow! signal. Nobody in the field believes the [Antonio] Paris explanation is correct.”
What does this mean? (1) Science works. Everyone can (and should) advance hypotheses, and once these are put out into the open, usually via publication, they are critically evaluated by peers. If a hypothesis is correct, it will stand the test of time. If not, like most hypotheses, it will be dismissed. The latter seems to be the case for Paris’ hypothesis, but the last word has not been spoken yet. There are many historic examples of hypotheses that were shredded to pieces by critics when they were first advanced, but later turned out to be correct.
(2) If, as it appears, a comet cannot explain the Wow! signal, it does not mean that the signal was a transmission from an alien civilization. There are a number of natural sources that could, in principle, explain the sudden appearance and disappearance of radio signals, such as fast radio bursts. Ohio State’s Big Ear telescope could have picked up the tail end of such an emission.
Another example of science at work—a particularly creative example—is a recent study by René Heller from the Max Planck Institute for Solar System Research in Germany, in which he challenged the scientifically inclined community to decipher a mockup alien message containing two million binary digits (0’s and 1’s) that he posted on twitter (and which is also available as an audio file). Heller provided a few clues to help people solve the puzzle, and after one month received 66 correct solutions from more than 300 replies.
Several conclusions can be drawn from this exercise. The Internet played a role in deciphering the mockup message, because people were able to communicate with and help each other, thus increasing the number who were able to find the correct solution. Also, people who were similar in terms of culture and education to the transmitter (in this case René Heller) had a greater likelihood of deciphering the message.
Of course, there would be no cultural similarity, or very little, between an alien civilization and humans. So I still have doubt that we could decipher an extraterrestrial message if we actually receive one. Even if we could, would we be able to figure out what the “words” actually mean? There are many languages of ancient human civilizations we still haven’t figured out! Heller makes a critical point, however: For the message to be decipherable, pictures have to be included in any binary code transmission linking symbols to objects. A picture says so much more than a thousand words!