I think we're not giving the aliens enough credit for the prescience to leave the spaceship there approximately 4.5 billion years ago (what's a couple of hundred million years between interstellar friends?) - it's quite astonishingly far-sighted, I thought games of Risk took a long time but to play the game with a turn taking 4+ billion years is something else entirely. Without it the stabilising effect on the Earth's axis wouldn't exist, we'd not have such regular tides and there wouldn't be the occasional funky lunar or solar eclipse - in point of fact there's a chance we wouldn't even be here but for that. Although admittedly they have shown a bit of forgetfulness and a distinct (but perhaps understandable) reticence to make contact since then, I'd be a bit embarrassed if I'd left my spaceship orbiting a planet for that length of time - perhaps we should consider charging them for parking, the sort of penalty charges for that would surely clear any global deficit.