[elwell]

> A true straight line from the starting point would take us off into space.

How do you know? "Straight" relative to what? The expanding universe? Would continuous adjustments need to be made to account for the displacement due to that expansion? Does this then assume some 'outer' universe / reference container?

[wongarsu]

Obviously he meant a geodesic though spacetime, assuming constant speed. Of course your speed does become relevant, but as long as it's positive, "space" seems broadly correct.

At least if we ignore the first 10km or so of your journey. A true straight line (geodesic) from the starting point would take us straight into a tree, hill or building. At that point the journey would end since humans can't phase through solid objects. You never reach another country.