Future one world government

If in the future, perhaps a hundred years or so if we ever populate other planets or moons🚀, we would have a need for a one-world government.🌍🌎🌏

A government that could make final decisions as a planet. Or if we were to make contact with intelligent space faring extraterrestrials 👽, we'd need a way to agree on our response.

⏺️What kind of government SHOULD we have and what kind to you think we'd ACTUALLY have?

⏺️Would we leave our respective countries as is and form a Federation or Confederation (like in Star Trek) of nations, like the UN?

⏺️Would we forego all independent states and form a Presidential/monarchical republic or democracy, constitutional or not, a communist one, an authoritarian or dictatorship? Other?

😬I'm hoping for anything other than an oligarchy or theocracy. Perhaps a provincial constitutional democratic republic would best fit for the large area and population. 🤔