How much do you know about computers? Unless you're a computer scientist, coder, or IT professional, the answer is probably not very much. But that might be a good thing, seeing as the most important tool of modern society is held together by a figurative toothpick; at least according to those very computer professionals. 

Isaac Asimov's famous "I Robot" science fiction series predicts that someday computers will become so complex that only other computers will be able to design them. When that happens, humans lose all ability to right the ship if it goes off course. According to these unsettling facts about computers, we're not there yet, but we're not far off. That, or everything is built on layer upon layer of antiquated code that we know how to change, but can't get to without tearing everything else down.

Here are 20 scary and little-known facts about computers and the internet.