Talk:vertical

I've included both the plumbline definition as well as the line through the center of the Earth. They're not the same- they would be the same if the Earth was spherical, but the gravity field (that is followed by the plumbline) isn't actually radial.Wolfkeeper 17:04, 3 August 2008 (UTC)

Strictly, vertical walls are never parallel on the surface of a spherical planet
https://en.wikipedia.org/wiki/Vertical_and_horizontal#/media/File:Vertical_wall_are_never_parallel.PNG Backinstadiums (talk) 12:23, 13 January 2023 (UTC)