We've all been there: you're discussing the recent launch of a rocket carrying a satellite to orbit, or what have you, and suddenly someone pops in and makes a comment like

> 
> Yeah, it's amazing and scary how powerful spy technology has become. They're probably watching us, as we speak!
> 
> 
> 

Now, I know that such a statement is extremely unrealistic. There are simply not enough satellites up there to be constantly monitoring every square meter of the planet. But do such statements have some truth in them?

I realize that, as far as spy satellites are concerned, many things could be unknown because of their classified nature. But is technology advanced enough to monitor something relatively small from space? Like what someone looks like (or at least what the top of their head looks like, assuming the view is from the top), or the security code on a piece of paper, etc?