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.
A new study suggests that by using the slingshot effect to propel self-replicating probes through interstellar space, an advanced extraterrestrial civilization should be able to visit every corner of the galaxy in a startlingly short amount of time. The Fermi Paradox, it would seem, is alive and well.
In movies, when aliens invade our planet, they usually have a ludicrous motivation. Like, they're after our water. Or our gold. (Hint: Asteroids have gold.) Space travel is incredibly difficult and expensive — so why would aliens actually bother to come and invade us? We asked some experts for reasons that actually…