How Self-Replicating Spacecraft Could Take Over the Galaxy

Forget about generation ships, suspended animation, or the sudden appearance of a worm hole. The most likely way for aliens to visit us — whatever their motive — is by sending robotic probes. Here's how swarms of self-replicating spacecraft could someday rule the galaxy. » 11/13/13 10:03am 11/13/13 10:03am