Cardinal directions are a derived idea from how the earth rotates. The sun rises on one side, sets on the other, and at right angles to both of those is the north star, which never moves, or an equivalent stellar constellation (the north star has changed over time, and is different in the southern hemisphere.) From these, you can infer a fourth direction, and you have cardinal directions. | Cardinal directions are a derived idea from how the earth rotates. The sun rises on one side, sets on the other, and at right angles to both of those is the north star, which never moves, or an equivalent stellar constellation (the north star has changed over time, and is different in the southern hemisphere.) From these, you can infer a fourth direction, and you have cardinal directions. |