Sometimes scientific reality surpasses science fiction. That's especially the case today, given all the planets we've discovered beyond our solar system. Now that we know how common exoplanets are, says SETI astronomer Seth Shostak, most of our alien invasion stories no longer make sense.

Over at NBC's Cosmic Log, Alan Boyle asked SETI astronomer Seth Shostak about alien invasion movies, and Shostak explained why they have become incredibly outdated in just the past few years. NASA's Kepler space telescope has allowed us to find hundreds of alien worlds, many of them in our immediate galactic neighborhood. The sheer volume of planets we've found — ranging from gas giants and ice worlds, to rocky worlds that might be Earthlike — suggests that planets are very common in the galaxy.

So why, exactly, would aliens invade Earth when there are so many other planets out there?


Writes Boyle:

NASA's Kepler planet-hunting mission suggests that there could be billions upon billions of alien Earths and super Earths out there. "What is it we have to offer, aside from some pretty good fish up in Seattle?" Shostak asked NBC News. "The answer is, not much. Just our culture, really. That's the only thing that they won't have at home, where the shipping charges are less."


Earth itself isn't exactly a valuable resource, it turns out. And even our culture might not be very interesting to life forms that communicate via pheromones, or see light in regions of the spectrum that we don't. This means that the fundamental basis for most alien invasion narratives is pretty much wrong.

Shostak described the typical alien invasion narrative:

They come here for the water, or they come because something is wrong with their reproduction. People love that sex angle. But I'm not going to go to the insects in the backyard because things have gone wrong with our reproduction — and those guys, at least, have DNA. Most of this doesn't make any sense whatsoever.


I think we should consider Shostak's comments and Kepler's discoveries as a call to narrative arms for science fiction writers. What new kinds of science fiction stories should we be telling about first contact between life from other worlds and life from our own? How can we incorporate what we know about planetary science into a new generation of science fiction stories where Earth is an ordinary rock among millions of other worlds?

Read more on NBC's Cosmic Log

Annalee Newitz is the author of the book, Scatter, Adapt and Remember: How Humans Will Survive a Mass Extinction. Follow her on Twitter.