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Science, Evolution, and Creationism, by the National Academies, focuses on teaching evolution in today's classrooms. Check out the other publications in our online store.
This is an artist's rendition of Earth's primordial environment and the beginnings of life.
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Earths Primordial Environment

In the beginning, Earth had a hydrogen based atmosphere, one which contained molecules in which hydrogen was a dominant constituent. Examples of such molecules include methane, CH4, hydrogen, H2, and ammonia, NH3. Such an atmosphere is also called reducing, as opposed to oxidizing. An oxidizing atmosphere is one that contains molecules with oxygen as the dominant constituent. Examples of those molecules include carbon dioxide, CO2, water vapor, H2O, and sulphur dioxide, SO2. In time, the early atmosphere of Earth evolved from a primitive reducing atmosphere to an oxidizing atmosphere.

Jupiter's atmosphere of today is an example of what all the primitive atmospheres must have been like. This is because, unlike smaller planets with less mass, Jupiter has such enormous gravity that very little of its original atmosphere has escaped.

Certain chemical reactions require energy to make them go (endogenic). That energy comes from ultraviolet (UV) light. Electricity in the form of lightning also serves that purpose. The Miller-Urey experiment showed that ultraviolet light plus lightning in a reducing atmosphere can produce long molecule chains which form the foundation of living cells. Earth's early environment was conducive to this process because the early atmosphere did not provide protection from ultraviolet light. Ultraviolet light can link small molecules together to make larger ones. (On the other hand, some forms of ultraviolet light can break apart large molecules).

On Earth today, the ozone layer, O3 absorbs almost all but the longest wavelengths of UV. On the early Earth, there was little free oxygen, so UV from the sun fell directly onto the surface of the Earth.

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The Fall 2010 issue of The Earth Scientist, focuses on rocks and minerals, including articles on minerals and mining, the use of minerals in society, and rare earth minerals, and includes 3 posters!

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Coacervates

In the warm primordial ocean, aggregates of amino acids, proteins, and other hydrocarbons coalesced into a form called *coacervates*. Organic polymers such as amino acids will spontaneously form coacervates...more

Whatís That Mineral?

Each type of mineral is made of a unique group of elements that are arranged in a unique pattern. However, to identify minerals you donít need to look at the elements with sophisticated chemical tests....more

Quartz

Quartz is the second most common mineral in Earthís crust. It is a member of the quartz group, which includes less common minerals such as opal, crystobalite, and coesite. Silica (Si) and Oxygen (O) are...more

Mica Minerals

Mica minerals make some rocks sparkle! They are often found in igneous rocks such as granite and metamorphic rocks such as schist. They sparkle because light is reflected on their flat surfaces, which...more

Feldspar

Feldspar is the most common mineral in the Earthís crust, so you are very likely to find it in the rocks you collect! It is found it all of the three rock types, but is most common in intrusive igneous...more

Olivine

Olivine looks like little green crystals. It is typically found in some igneous and metamorphic rocks. Often the crystals are so small that you need to use your hand lens or magnifying glass to see them...more

Type of Minerals

So far, over 2000 minerals have been found, and every year new ones are discovered. This is a pretty overwhelming number of different types of minerals, however, you don't need to know them all to be...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