It’s a common staple of invasion fiction to suggest that aliens from beyond the stars may visit our planet with the intention of stealing our resources. Water, Gold, Oxygen, and other elements have all had their place in the spotlight for an invading alien species making the decision to get humanity out of the way and start plundering. This “space pirate” view of alien invasion does, however, have one big problem. And it’s a question that ultimately leaves us with the prospect that any invading alien race would inevitably be interested in one thing – life.
While it may be virtually impossible to predict the actions or motivations of an invading alien species, we can draw several parallel based on things we have learned elsewhere. And of course with that in mind we can say that it’s unlikely that an invading alien force would ever come to Earth with the intention of stealing our resources. Though water is abundant on Earth proportionally to the rest of its surface, our entire planet is only a drop in the bucket compared to the vast quantities on Saturn. Though we may have diamonds, they are far more rare here than they would be on Uranus where NASA scientists estimate there may actually be an ocean of liquid diamond. Even oxygen, an element once thought to exist exclusively on our own planet has been found by scientists at the European Space Agency. The molecules, which were thought to be only part of a far larger environment rich with oxygen would be easy enough to harvest by any space faring alien civilization if doing so was necessary. Gold, the metal inspiring the alien invasion in the film Battlefield Earth was first detected in abundant quantities near the asteroid Eros. The estimated value of the rock placed it at somewhere around $20 trillion worth of the stuff (four times the amount ever mined on Earth).
But there is one thing Earth has in abundance that doesn’t seem to be very many other places – as we have seen. In addition to having all the necessary components of life distributed throughout the planet’s sphere, the very presence of life itself may be an interesting target to an invading or passing alien intelligence if they have not found a way to spontaneously manufacture more life on their own. An alien race passing through our solar system may find this a tempting reason to visit. Fortunately for us, one of the requirements for this precious resource is that it continue to stay alive. And so the alien invaders would likely not attempt to wipe out Earth wholesale – even if they had the technology to do so.
Of course this is also assuming they’re hostile to begin with.