DPTT
Striker
So you cannot disprove the distance between Rio and Sydney thenNot at all.
You say the globe is right without knowing you're even on a globe.
Not at all.
I can check any distance if I have the means to transport and know the speed and time to the destination from departure.
A plane would offer me a more direct route to a destination where obstacles would be an issue for other transport.
A level flight would then offer me my approximate distance.
But you're still using a globe as the premise for measurement.