💾 Archived View for jsreed5.org › log › 2023 › 202303 › 20230314-extraterrestrial-signals.gmi captured on 2023-07-22 at 16:53:28. Gemini links have been rewritten to link to archived content
⬅️ Previous capture (2023-04-19)
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One high-tech endeavor of humanity is the search for life on other planets, especially intelligent life. We've built vast radio telescopes, such as the Low Frequency Array in the Netherlands and the Allen Telescope Array in California, for just this purpose.
Our own radio communications have evolved in the last several decades. We began with fully analog systems transmitting audio data in the clear: any device capable of receiving signals at the given frequency could hear everything. That soon changed to analog encoding of digital signals--already indecipherable to living organisms but perfectly understandable to a computer.
The digital signals were direct encoding, so foreign machines might still read and decipher them with little difficulty. Then came encryption: simple rotation ciphers, followed by polyalphabetic substitution schemes such as Enigma. Mathematical methods such as public-key cryptography are even more complicated, requiring not only knowledge of the private key but deriving what mathematical function was used to encrypt the message. And in the most extreme cases, messages are encoded with one-time pads, making them impossible to break even theoretically.
If intelligent life does exist elsewhere in the universe, it's possible they will pick up radio signals from us. But while it will likely deduce that Earth is so radio noisy due to artificial sources, what we say will be utterly unintelligible to them. They may not even bother trying to figure it out.
This issue applies both ways. Were we humans to intercept an extraterrestrial signal of artificial origin, there's no guarantee that we could decipher it into something meaningful. If intelligent aliens behave anything like we do, we have good reason to assume the opposite.
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[Last updated: 2023-03-14]