For the last 15 years, scientists have been detecting strange radio bursts from deep space that appear mathematical in nature, reports New Scientist. The fact that they display a mathematical pattern is the linchpin: There are no known natural phenomenon capable of generating radio bursts with this kind of pattern.
So either these radio waves represent some yet undiscovered celestial event, or they are being produced by some kind of technology. In other words, if they do have a technological origin and they aren’t being generated by us, that means they could be signals from an extraterrestrial intelligence. Yep, that’s right: aliens.