Earth's surface is like 71% water, give or take. I think that's just the oceans, I'm not sure how much of that is rivers and lakes.

[ Yuri takes a moment to think about it. ]

A different world would be an alien, I guess. Technically anyone from another country or planet is an alien, so you'd be an extra-extra alien. As it stands, we're all in the same place now so I guess that's the only thing that matters.