Isotropy and anisotropy: When a material is attacked by a liquid or vapor etchant, it is removed isotropically (uniformly in. all directions) or anisotropic etching (uniformity in vertical direction).
Some Questions Do Remain: 1  If the Earth was flat, we could travel to the place where the Earth and sky met. But we canât. 2  If the Earth was flat, we could reach the place where we could reach out and touch the Sun. But we canât. 3  If the Earth was flat, we could fall off the horizon. But we donâ 4 t. If the Earth was flat, it would simply fall.
Given this history, it should come as a surprise to anyone that any human being existing in the developed world right now should still consider the idea of a flat Earth probable. Since the mid-1800s, though, modern pseudoscientists have been trying to prove that the Earth is flat.