What are some theories on why we haven't been visited by aliens yet?
What are some theories on why we haven't been visited by aliens yet? Originally Answered: What are some theories on why we aren't visited by aliens yet? The classic Fermi paradox makes for very interesting analysis. There are some very compelling theories on why we haven't been visited by or been made aware of other intelligent life forms out there if there are potentially over a 100 billion Earth-like planets out there. To understand these theories, there are certain concepts and theories one needs to be familiar with: Kardashev Scale, Drake's Equation, Great Filter, and the Wow! Signal. This is a longish answer, but bear with me while I get to it. I took a fair bit of help from this Wait But Why post to give my answer a skeleton. Tim's done a great job of it and I'd encourage everyone to read it. I've added a lot of extra information, I hope you find it relevant. First of all, how do you define alien life? Hardcore weirdos like in our famous movies o