Laplace would be surprised to hear that. That is true on a spherical planet, and on an ellipsoid of rotation, only on the equator and at the poles. It's complicated.
No two vertical lines are parallel as a plumb line always points to the center of the earth.
Laplace would be surprised to hear that. That is true on a spherical planet, and on an ellipsoid of rotation, only on the equator and at the poles. It's complicated.