四方上下曰宇。宇虽有实,而无定处可求。往古来今日宙。宙虽有增长,不知其
始之所至。
In ancient China, all the space named “Yu”. Although the Yu has been an entity, there seems never a certain place to search for it. The past and the future called “Zhou”. Although the Zhou has been growing, when it had started from and when it would eventually end up with are all unknown.