Evan Curry, author of the upcoming book, Out of the Black, from his popular Odyssey One series, discusses the idea of an Alien invasion on earth.
The words invoke imagery from a hundred movies and books, from War of the Worlds to Independence Day and beyond. In the Odyssey series I play with the common tropes of the genre, twisting some and just enjoying others, but the common question has a tendency to remain… Even if we accept the central premise, is any of it really possible? Why would aliens bother with us anyway? More importantly, for a military science fiction writer like myself at least, could we beat them back? Could we win?
Better minds than mine have given it a lot of through, including the US Military if rumors hold some truth to them, but it always seems to boil down to us poor humans having something the big scary aliens want. Alright, that makes sense on the surface, so what could we have? Air? Water? Gold or other precious metals?
No, none of those make sense. Any space faring culture would more easily acquire those in space at any asteroid belt, out in the Oort Cloud, or any of a thousand other possibilities. So why invade? Two possibilities make sense, a lot of sense.
First, Aliens may want or need our Biosphere. Air, Water, even food can easily be manufactured or sourced from accessible resources in space but the complicated linking of everything that makes up the world we live on may be the rarest of the rare. It may also be essential to life, not just as we know it, but as the universe understands it.
We like to say that we humans are star stuff, and that’s very true. The seeds of life, whether you believe abiogenesis or creationism, came from the heavens above. The process through which we evolved here on Earth may end in wildly different places on another world, but that starting point may well remain a constant. DNA, the habitable zone, and the basic rules for all life as we know it could be universal.
So for those invaders, Earth would be a jewel floating in an eternal desert. Priceless, and worth having at any cost.
No matter how advanced these aliens are, however, they would be fighting at a sore disadvantage. Earth is our home, we evolved here, and we know all its secrets. Alright, we know some of its secrets. Our supply lines would be short, we could easily hide and strike from the shadows, and generally make it very expensive to try to hold the planet. They could easily take it, any species capable of getting here is going to walk right over us in the initial invasion, but we could make it unbelievably expensive to hold.
They couldn’t just wipe us out, that would almost certainly destroy the biosphere that attracted them. Hell, we’re doing a great job of that just by accident, so believe it or not the Earth’s biosphere is incredibly fragile in the short term. Certainly, it would recover, but that could take decades or centuries and presumably our uninvited guests want to move in now. Against such a foe, our best defense might be putting a nuclear gun to our own heads and trying to out crazy them. We’re pretty good at that, just check the history of the cold war.
So, yes, we could probably beat back such an invasion by hook or by crook.
The second possibility? Oh yes, them. Well, if the Earth is ever invaded by a species that doesn’t need our biosphere… we lose. We will never see such an enemy coming, they would hold all the cards, and wiping us out would simply be good security.