Geoscience Reference
In-Depth Information
EARTH-SUN GEOMETRY
AND THE SEASONS
C H A P T E R T H R E E
Of all the spatial relationships that geographers study, the Earth-Sun relationship has the greatest impact on the
way Earth functions and the existence and character of life as we know it. In the context of physical geography,
this relationship is especially important because most of the physical processes on Earth are powered by incoming
radiation received from the Sun. Although Earth receives only about one-half of one-billionth the amount of energy
that the Sun radiates, this tiny amount is nonetheless critical to powering physical processes and life on the planet.
At first glance it might appear that the Earth-Sun relationship is simple and easy to comprehend. In fact,
this relationship is very complex because it depends on many different geographic variables such as latitude, the
position of the Sun in the sky, the time of year, and the nature of the Earth's rotation and axial tilt. It is essential to
understand the information in this chapter because it provides the foundation for many geographic patterns you
will see in the remainder of the topic.
