http://en.wikipedia.org/wiki/Mentor_(satellite) http://en.wikipedia.org/wiki/Mentor_(satellite) 100+ meter diameter radio telescopes pointed at the earth. That

http://en.wikipedia.org/wiki/Mentor_(satellite) http://en.wikipedia.org/wiki/Mentor_(satellite) 100+ meter diameter radio telescopes pointed at the earth. That's the same size as the largest steerable ground-based radio telescopes. Makes you wonder what they can hear.