The Earth is made of several systems or "spheres" that interact.
Processes operating in the Earth system take place on spatial scales
varying from fractions of millimeters to thousands of kilometers, and on
time scales that range from milliseconds to billions of years.
Examples of instantaneous - breathing; rotation of the Earth;
Examples of long term - making coal; plate tectonics
all of the rocks and "hard parts" of the Earth
all of Earth's water
all living things
the blanket of gases surrounding the planet
the universe surrounding the Earth
The Earth system is characterized by numerous overlapping cycles in which
matter is recycled over and over again. Cycles involve multiple spheres
and systems interactions.
Examples of cycles: day and night; rock cycle; seasons
The Earth system is powered by energy from two major sources: the Sun and
the planet's internal heat.