Why would aliens come all this way just to invade Earth?

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… » 5/02/13 1:30pm 5/02/13 1:30pm

How to Write a Killer Space Adventure Without Breaking the Speed of…

Is it possible to have a wild, exciting space adventure without resorting to magic? Or is there just no way to imagine conquering the vastness of the cosmos without warp drives, hyperspace, miraculous shielding and other fancy devices? » 9/17/12 11:48am 9/17/12 11:48am