Aliens man, they’re out there, right? I mean, the universe is far too big for us to be the only intelligent beings. Right? So, why haven’t we encountered any, that we know of? SETI, the active Search for Extra-Terrestrial Intelligence, has been probing the galaxy with radio signals for over a century now. As of this post, they’re never received a signal from stellar systems. Here are the top theories as to why.