People have been claiming to own the moon for over 250 years

TLDR summary: Anyone can claim anything

Within the next decade though I think this question is going to take on a more interesting twist. The Senate, and has just passed legislation that says "if you can mine some resource from an exoplanet resource, you own it." which basically enables folks to mine asteroids, and as far as the US is concerned, keep the profits[1]. Assuming this becomes law, you can imagine that someone who landed a robot on the moon, and recovered water from the regolith, would be in a position to make a pretty profit selling that water to the first humans that land for an extended stay. Then there is the whole colonizing thing, if you live there and raise crops (see the reference in The Martian) international law recognizes a colonizing right.

So for the last 250 years this has been a joke because nobody could actually go to the moon for an extended stay, but that will change, perhaps sooner than many people think.

[1] https://www.reddit.com/r/space/comments/3snvnx/us_congress_l...