Chapter 1 Introduction to Earth Science
Summary
1.1 What Is Earth Science?
Earth science is the name for the group of sciences that deals with
Earth and its neighbors in space.
• Geology means “study of Earth.” Geology is divided into physical
geology and historical geology.
• Oceanography is the study of the Earth’s oceans, as well as coastal
processes, seafloor topography, and marine life.
• Meteorology is the study of atmosphere and the processes that
produce weather and climate.
• Astronomy is the study of the universe.
The nebular hypothesis suggests that the bodies of our solar system
evolved from an enormous rotating cloud called the solar nebula. It was
made up mostly of hydrogen and helium, with a small percentage of
heavier elements.
• Shortly after the Earth formed, melting occurred in the Earth’s interior.
Gravity caused denser elements to sink to Earth’s center. Less dense
elements floated toward the surface. As a result, Earth is made up of
layers of materials that have different properties.
1.2 A View of Earth
Earth can be thought of as consisting of four major spheres: the
hydrosphere, atmosphere, geosphere, and biosphere.
• The hydrosphere is the water portion of Earth.
• The atmosphere is an envelope of gases that surrounds Earth.
• The geosphere is the layer of Earth under both the atmosphere and
the oceans. It includes the core, the mantle, and the crust.
• The biosphere is made up of all life on Earth.
Because the geosphere is not uniform, it is divided into three main parts
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