Why the Moon's Farside Has No Smooth Dark Maria

The Moon's two faces don't match. The nearside is covered in smooth dark maria, the plains that give the Moon its familiar markings; the farside is rough and battered instead. A likely explanation is thickness: if the farside crust is thicker, molten material from the interior has a harder time flowing up to the surface and pooling into those dark, smooth plains. Same body, different plumbing — and one hemisphere ends up looking like a different world.