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Become a nitrogen atom in the nitrogen cycle in our Traveling Nitrogen Classroom Activity Kit/Game. See all our games, activity kits and classroom activities.

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The Environment of the Earth in the Past

Calculations show that the Earth had large oceans very early in its history. During this time the Earth should have been frozen because of the weak luminosity of the sun at that time, nevertheless the fact that there was a large and vigorous ocean suggests that the Earth must have had a large and vigorous atmosphere in place to keep the surface warm. The warm early ocean of Earth was ideal for the development of life. The earliest fossils show that there was life on Earth at least 3.8 billion years ago (see the geologic record for the corresponding epochs of the Earth's history).

The atmosphere of the Earth came from, and continues to come from volcanoes, which produce a great deal of water vapor, carbon dioxide and other gases. Over the course of time the composition of the atmosphere has changed significantly. In particular, the earliest atmosphere was very rich in carbon dioxide (like present Mars and Venus). The present atmosphere is 80% Nitrogen and 20% Oxygen. It was life on Earth which was largely responsible for transforming the content of the Earth's atmosphere to its present composition.

The changes in the atmosphere, as well as the changes to the locations of the continents, have contributed to very significant changes in the climate of the Earth. The surface of the Earth has seen extremely high temperatures, as well as extremely low temperatures. Today's concern about global warming is part of a long history of Earth's variability with regard to climate.

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Our online store includes issues of NESTA's quarterly journal, The Earth Scientist, full of classroom activities on different topics in Earth and space science, ranging from seismology, rocks and minerals, oceanography, and Earth system science to astronomy!

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The air of Neptune is extremely cold, with temperatures of -270 degrees to -380 degrees. The air is made of complex molecules, the same sort of molecules that we see coming out of cars on earth in the...more

The Environment of Uranus

Uranus' atmospheric environment is one of strong gravity, high pressure, extremely cold temperatures of 50 K to 120 K (-270 degrees F to -380 degrees F). Moreover there is energy from lightning, ultraviolet...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