The Earth as viewed from the Moon during the Apollo 8 mission.
Click on image for full size
Image courtesy of NASA

Earth as a System

The first time people got a glimpse of the whole Earth was December 1968. Apollo 8 astronauts, en route to and from the Moon, took pictures of the Earth from space.  In their photographs, the Earth looks like a small blue and white orb in a sea of black space.  Looking at the planet from that vantage point it's easy to see that all its components- the living things, the air, the water, the ice, and the rocks - are connected.  Everything on Earth is in the same boat floating through space - a system.

Since the 1980s, NASA scientists have been studying the Earth as they study other planets - mainly from above with satellites. Based on this way of looking at Earth, they developed the idea of Earth system science.  

"From space we can view the Earth as a whole system, observe the net results of complex interactions, and begin to understand how the planet is changing in response to natural and human influences," NASA explained in its 2003 Earth Science Enterprise report.

There are five parts of the Earth system, often known as "spheres." Each part has its own collection of materials and dynamic processes that make Earth an ever-changing place. However, each part of the Earth system does not operate on its own.  They all interact with other parts in many ways.

  • The atmosphere extends up from the Earth surface for several hundred kilometers. The lowest part is home to clouds and weather.
  • The biosphere is all living things including plants, animals, protists, fungi, Achaea, and bacteria.
  • The geosphere generally extends from the Earth surface to its core including all rocks, molten rock, sediments, and soils (although there are important living components to soils as well).
  • The hydrosphere includes the ocean, rivers, lakes, streams, groundwater, water vapor, and even puddles.
  • The cryosphere is the frozen part of the Earth system and includes icy aspects of our planet like snow, glaciers, and sea ice.

The Sun, although not literally part of the Earth, has a large impact on the Earth and so it is also considered a part of the Earth system too. Almost all the energy on Earth is derived from the Sun.   The factors outside the planet, like the Sun and solar system, which have an impact on the Earth system, are sometimes collectively called the Exosphere.

Last modified August 16, 2013 by Roberta Johnson.

You might also be interested in:

Traveling Nitrogen Classroom Activity Kit

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

The Cryosphere

The cryosphere includes the parts of the Earth system where water is in its frozen (solid) form. This includes snow, sea ice, icebergs, ice shelves, glaciers, ice sheets, and permafrost soils. Approximately...more

The Earth System Is Changing

Earth is a dynamic place. Matter cycles around the Earth system in various ways.  Rocks form, erode, melt, and form again through the rock cycle. Water flows through the water cycle. Elements move through...more

Chemistry

Chemistry is the study of matter, energy, and their interactions. Chemists study the composition of substances, their properties, and how they react with each other under varying circumstances. Indeed,...more

Geologic Findings Undermine Theories of Permian Mass Extinction Timing

New scientific findings by geologist Robert Gastaldo of Colby College in Waterville, Maine, and colleagues call into question popular theories about the largest mass extinction in Earth's history. A paper...more

Atmospheric Science Literacy - Essential Principle 4

Earth's atmosphere changes over time and space, giving rise to weather and climate. Fundamental Concept 4.1 Weather is the state of Earth's atmosphere at a particular place and time. The climate of a particular...more

Atmospheric Science Literacy - Essential Principle 3

Atmospheric circulation transports matter and energy. Fundamental Concept 3.1 Horizontal and vertical energy imbalances in the Earth System produced by unequal heating of Earth's surface create movement...more

Atmospheric Science Literacy - Essential Principle 2

Energy from the Sun drives atmospheric processes. Fundamental Concept 2.1 Earth receives energy in the form of electromagnetic radiation from the Sun. Some of this solar energy is absorbed by the atmosphere,...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA