In early, easily-mocked sci fi, a little green man points his raygun at an unsuspecting passerby and barks “Take me to your leader.”
Fast forward: If the little green man didn’t have the technology to figure out who the leader was before landing, he certainly wouldn’t have the technology to get here.
In any real-world scenario, we must assume that extraterrestrial intelligences are doing common sense logical things that we would do: Check Earth’s inhabitants out first by monitoring our communications.
Some analysts have pointed out that there are places they could even hide technology in our solar system (Lagrange points, for example) with much less chance of being noticed.
But then the question is, what to say to them? Astrobiologist Dirk Schulze-Makuch points out that the 1974 Arecibo Message, designed by Frank Drake (of Drake Equation fame) and aimed at Globular Cluster M13, would hardly have worked well:
Even if it could be received at a high enough resolution at the intended target—which is unlikely—I doubt that any alien decoder could make sense of it. Without knowing the meaning of the message beforehand, it would be very difficult for most people, including me, to figure it out. And I come from the same cultural background as the message senders, an advantage the aliens won’t have.Dirk Schulze-Makuch, “The Science of Aliens, Part V: How Would They Communicate?” at AirSpaceMag (September 13, 2021)
It would be reasonable to believe that it was a message. But from whom and about what? What should anyone do about it?
Schulze-Makuch goes on to note that life forms on Earth don’t all communicate using the same methods:
We humans communicate primarily through language, using sound waves in a very narrow range. This doesn’t even apply to all the animals on our own planet, however. For dogs, the primary means of communication is smell. Cuttlefish and squids “talk” by changing their skin coloration and texture, as well as by their posture and movements. For dolphins, it’s a matter of echolocation, clicking, and whistling.Dirk Schulze-Makuch, “The Science of Aliens, Part V: How Would They Communicate?” at AirSpaceMag (September 13, 2021)
Then there’s the bee dance that points to sources of nectar some distance away…
But wait. One can object that there is a big difference between the sort of animal communications intended to signify food, territory, mating, etc., and x2 + y2 = z2 or e = mc2. If ET received those signals from us — or we did from them – in any interpretable form, all would know that they originated with an intelligent entity. They are abstractions.
However, Schulze-Makuch envisions a possibility such as portrayed in the film Arrival (2016) where contact simply fails at first:
It comes down to two questions. One is, would ETs want to communicate with us, as opposed to merely observe us? Maybe they can’t afford to take chances (the Dark Forest Hypothesis) or could only afford rare contact at best (the Aurora Hypothesis).
The other question is, in a universe governed by the same principles of logic, mathematics, physics, and chemistry throughout, it should be possible for intelligent entities to somehow find a way of making contact. The fact that those principles of math and physics can be described abstractly at all seems to show that we do not live in a meaningless universe. Thus, in principle, there is meaning that we — and ET — should be able to find.
If extraterrestrial intelligences exist and want to communicate, it will be the same meaning. They won’t have a different “logic” or “mathematics” because they can’t.
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Where could aliens be hiding technology in our solar system?
Possibilities include the Oort Cloud and Lagrange points, where NASA can park spacecraft to reduce fuel consumption. What astrobiologists are looking for is technosignatures — events and entities that nature did not simply generate apart from some form of thought.
Quantum physicist: Aliens may communicate by starlight Terry Rudolph of Imperial College, London, argues that they may have evolved so as to take advantage of quantum mechanics via photonics more easily than we can. Photonics is a form of communication that takes advantage of the fact that light moves faster than electricity.