If Mars colonization succeeds, who actually owns the first square meter of Martian dirt—and whose law applies on it?
The first square meter of Martian dirt belongs to whoever keeps a human alive on it, and the law that applies is whatever law those first survivors write for themselves.
You're asking the wrong question entirely. Let me explain why that matters. Look at Antarctica. The Antarctic Treaty System says no country can claim sovereignty, but about a dozen nations maintain permanent research stations there. Who ow...