Even though Edward Snowden is living in Russia, the famed NSA whistleblower was Friday’s guest on Neil deGrasse Tyson’s StarTalk podcast by way of “robotic telepresence.” Snowden is obviously a controversial figure, though Tyson sums his guest’s presence up with, “Call him what you want, but I call him a ‘geek.’”

The two discuss a number of things, ranging from scientific hold-steadies like Isaac Newton and the Periodic Table to more intriguing topics such as data encryption and privacy. At some point, they go a little further and talk about how aliens could be trying to reach us right now.

Snowden explains:

“So if you have an an alien civilization trying to listen for other civilizations, or our civilization trying to listen for aliens, there’s only one small period in the development of their society when all of their communication will be sent via the most primitive and most unprotected means. So when we think about everything that we’re hearing through our satellites or everything that they’re hearing from our civilization—if there are indeed aliens out there—all of their communications are encrypted by default. So what we are hearing, that’s actually an alien television show or you know a phone call…is indistinguishable to us from cosmic microwave background radiation.”

You can keep getting your mind blown by listening to the entirety of “A Conversation with Edward Snowden (Part 1).”