Funktional principle
Time
Date
Sub-solar point
True noon
Unique
Date and season
The date line is the daily
path of the sun: in the morning
at sunrise over the Indian Ocean,
at noon over Africa and in the
afternoon it moves towards America.
Every day the sun follows a different
course between the tropics, seasons come
into being. In the winter and autumn, it
stays in the southern hemisphere, in
summer and spring the sun migrates north
of the equator.
