Why the earth is round?

Our never-thought to ask question for today is： Why is the earth round？ Why not a cube？ Because…， because really big things like to be round for some reason. Exactly right. And that reason is gravity.

Since gravity works equally on everything， there would be a tendency to pull those uneven places down. The surface would even itself out. The only geometrical object in which every point on the surface is the same distance from the center is a sphere.