Spain

Rome

I take it geography is not one of your strong subjects.

Now for real. Distance from A and B (for example 400km). For car it will be... 400km. But if you believe in GPS - measure this distance in plane. It will be much longer. Why? If earth is flat then distance should be nearly equal. Why it doesn't? Because plane high - which is just radius of CIRCLE - is longer. Simple proof of curvation of earth

An interesting hypothesis. Let's put it to a simple test.

For the sake of the discussion, let's assume that the Earth is a perfect sphere with the circumference of

and the radius of

. This should allow for a satisfactory degree of precision, but you're welcome to provide more accurate calculations if you object to this.

For simplicity, let's take a ground-level great-circle distance of 400.75km - 1% of the circumference. Since we're dealing with a perfect sphere, the angle created by point A, the centre of the sphere, and point B will thus be

or

.

Most commercial planes cannot fly higher than 12km (See:

http://spaceplace.nasa.gov/review/dr-marc-technology/rockets.html). So, let's try to figure out the great-circle distance between the points

above A and

above B.

Since we're now constantly

above the surface of the sphere, the radius of the relevant circle will be

, giving us a circumference of

. The length of an arc of this circle delimited by an angle of

will therefore be

- a difference of approximately 1% from the original number.

This also means that if we were to circumnavigate the entire sphere, the difference in distance travelled on the ground and 12km up in the air would only be 75km - hardly a big deal. Now, bear in mind that we've introduced a lot of simplifications - the round Earth model does not postulate that the Earth is a perfect sphere, nor is it possible to traverse long distances on the ground along a great circle. Aeroplanes do not magically pop up 12km above the ground but rather gain their height over time, and they also do not travel in a great circle.

Overall, this is very simple geometry. The fact that you posted your assertion here without even taking the 10 minutes it takes to verify your claim is a testament to how blindly people can believe what they were indoctrinated into.