Why do we have the International Date Line?

Our calendar day is based on one rotation of the earth on its axis. The time it takes is about four minutes less than 24 hours. Since the rotation is continuous, there is no natural division between one day and the next. At some place on the gl obe,the sun is always rising, bringing a new day. This would be confusing if we did not invent a division between one calendar day and the next.

This manmade division of the days is the International Date Line which zig tags down the center of the Pacific from pole to pole. This line divides Monday from Tuesday. It is the place where each new calendar day is born.