i actualy beleive that it was thought out by some expersts long ago, considering its 12pm on one side of the world simultaniously 12am on the other side. then they broke it down into 24 measurments, then eatch measurment by 60 to minutes, then 60 seconds into a minute, and the fact that the sun is on the other side of the world when it is exactly 12am, we never lost track of time.