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In an interview with Neil deGrasse Tyson, Snowden offers a fascinating explanation for why aliens have never communicated with us.

Neil deGrasse Tyson, Edward Snowden, and alien communication: a compelling scientific trifecta. While it’s widely known that the whistleblower has some tenacious opinions on the spheres of communication and privacy, he offered an intriguing theory on why we may have never heard from aliens in his latest interview on Tyson’s “StarTalk” podcast.

According to Snowden, his theory might help answer one of the most baffling cosmological puzzles known to man — since the universe is extremely vast and old, why do we have yet to discover or hear from any sign of alien life? Surely we aren’t the lone civilization in over one hundred billion galaxies, and by now the older civilizations should have discovered more sophisticated ways of intergalactic communication.

Snowden believes that the answer to this question, called the Fermi Paradox, could all boil down to technology and security issues, particularly encryption. He believes that, if there’s a universal need to keep communications secure, it may make it difficult or even impossible for us to distinguish alien messages from cosmic background radiation leftover from the Big Bang. Basically, it’s possible that alien signals could be hitting our satellites at this moment, but encryption is preventing us from recognizing them.

Essentially, Snowden supposes that if aliens are intelligent, they’ll understand the importance of encryption for security purposes. But if they’re encrypting their messages, just like we do, we’ll probably never distinguish them from the noise of cosmic background emissions. “If you look at encrypted communication, if they are properly encrypted, there is no way to tell that they are encrypted,” he said. “You can’t distinguish a properly encrypted communication from random behavior.”

Snowden has done countless interviews on the privacy issues surrounding technology, but leave it to an astrophysicist like Tyson to question how it all relates to aliens. Naturally, he upheld his air of scientific skepticism, asking Snowden how he’s so sure that alien civilizations have the same security issues as we do. Maybe alien civilizations have it all figured out and don’t have to worry about their communications being intercepted by their governments.

Snowden agrees — perhaps alien civilizations are a little bit more politically sophisticated than our own.

Nonetheless, it’s pretty frustrating to consider that encryption could be preventing us from detecting alien communications. The answer to one of the most mind-bending mysteries of our existence — do alien civilizations exist? — could hit our satellites at any given minute, and we would never know.

Listen to Tyson and Snowden’s interview here.