Prince Henry, nicknamed "The Navigator" was a governor/ruler of Portugal during the time period of European exploration. He created a school of navigation in which brought the skills of boat builders, map makers, etc. He sent explorers out to find shorter sea routes to the source of expensive spices. He led the way of the "Age of Discovery".
the change between day and night is caused by the rotation of earth on its axis ...the changing of lengths of day and nights depend on where you are on earth and the time of year. also, daylight hours are affected by the tilt of earth's axis and its path around the sun
