What is Fermi Paradox?

The Fermi Paradox is the confusing question of why we see no aliens when the universe seems like it should be overflowing with them. Imagine looking at a dark ocean at night and wondering where all the other boats are, even though there are billions of stars.

Think about Earth as a single house in a giant subdivision that has existed for 13 billion years. We have only been living in our "house" with lights on for about 100 years. The Galaxy is like a massive apartment building where every room is a star system. Most stars have planets, just like most apartments have rooms. If even one neighbor started traveling between apartments, they could visit all of us in just a few million years. That is a blink of an eye in cosmic time. Yet, we look out our window and see only darkness. We expect to hear signals from their Wi-Fi or see lights from their ships, but the sky remains quiet.

Scientists have many ideas for this silence. Maybe advanced aliens are like shy cats; they are there, hiding in the bushes, waiting until we get better at listening. Or perhaps they built their civilizations so far away that the distance is too great to cross easily. Some think we might be missing a Great Filter, a tough hurdle that most life fails to pass before it can travel across space. It could also be that alien civilizations are short-lived and burn out quickly, like fireflies flashing in the dark for only a moment before disappearing forever.

The paradox remains because the math says there should be so much activity, but our eyes see so little.