Why is the earth round?

Question

Why is the earth round?

Answer 1

Is it round? This is due to gravity. Gravity pulls with equal strength in all directions; therefore any variations from a spherical shape will lead to gravitational forces that bring the shape back into that of a sphere.



This is without considering the rotation of the earth, however. The rotation of the earth adds centrifugal effects, which cause the earth to bulge slightly at its equator and flatten slightly at its poles. (This is like twirling a rock on the end of a string and then letting go--the rock flies away from the twirler.) Because of these centrifugal effects, the distance from the center of the earth to the surface of the earth is about 0.33% shorter at the poles compared to the equator.

Answer 2

Gravity

Answer 3

It is not exactly a sphere. It is more like an oblated spheroid (or an ellipsoid of revolution), to get technical. It bulges near the equator and is somewhat flattened at the poles.

Gravity and centrifugal force are the primary factors in the determination of its shape.

Answer 4

It really is square but the government made millions of world globes and we too embarassed to tell the public we made another mistake.

Answer 5

Rotation and gravity.

Answer 6

because flat is SOOOO 600 years ago! :P