The search for extraterrestrial intelligence (SETI) has traditionally hinged on detecting electromagnetic waves, most commonly radio waves but also infrared and x-ray radiation as well as optical pulses at specific frequencies. But in the absence of knowledge about the specific nature of extraterrestrial civilizations, we need to explore all sources of communication possible and not just ones based on electromagnetic waves. Thus the message we would send or receive could and should include everything from symbolic signals to actual physical samples of material signifying the presence of intelligent life. SETI is an endeavor fraught with such momentous potential significance that it would be foolish to hinge it on physics alone. We need to employ other sciences in its service.
For doing this it’s extremely valuable to turn the question around and ask what we would do if we were to announce our presence. What kind of messages would we send to a potential ET listener? This line of questioning is valuable but it always includes the significant pitfall of suffering from anthropocentrism. It’s all too easy to believe that ET thinks just the way we do. Nonetheless, thinking from a human perspective opens the way toward understanding various potential forms of communication. So with the caveat that we should not constrain ET to fit our shoes too well, it’s worth pursuing this line of thinking.To read more, click here.