Scientists call this question the Fermi Paradox. Mathematics (especially a thing called The Drake Equation) says there SHOULD be planets out there supporting intelligent life, but we have no actual evidence that there ARE any.
IT’S A FUCKING PARADOX, RIGHT?
According to astrophysicists, there are currently TWENTY answers to the Fermi Paradox i.e. explanations for why we haven’t heard from any aliens.
1. Aliens don’t exist… Duh. What happened on Earth was such a random collision of a billion unique circumstances, it has not happened twice. It COULD happen at some point in the future. But so far, it just hasn’t.
2. Aliens exist, but they’re basically goo… Aliens are just a bunch of algae somewhere. Their existence is impossible for us to detect. Also, who gives a shit? It’s goo. No one cares about goo.
3. Aliens don’t have enough bars on their space phones… Intelligent aliens exist, but don’t have the technology to send (or receive) messages over sufficiently large distances. So basically, Aliens are on Sprint.