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  2. Geochemistry - Wikipedia

    en.wikipedia.org/wiki/Geochemistry

    This can be the result of chemical reactions, phase changes, kinetic effects, or radioactivity. [1]: 2–3 On the largest scale, planetary differentiation is a physical and chemical separation of a planet into chemically distinct regions. For example, the terrestrial planets formed iron-rich cores and silicate-rich mantles and crusts.

  3. Oxygen cycle - Wikipedia

    en.wikipedia.org/wiki/Oxygen_cycle

    The Earth's atmosphere, hydrosphere, and biosphere together hold less than 0.05% of the Earth's total mass of oxygen. Besides O 2 , additional oxygen atoms are present in various forms spread throughout the surface reservoirs in the molecules of biomass , H 2 O , CO 2 , HNO 3 , NO , NO 2 , CO , H 2 O 2 , O 3 , SO 2 , H 2 SO 4 , MgO , CaO ...

  4. Biogeochemical cycle - Wikipedia

    en.wikipedia.org/wiki/Biogeochemical_cycle

    A biogeochemical cycle, or more generally a cycle of matter, [1] is the movement and transformation of chemical elements and compounds between living organisms, the atmosphere, and the Earth's crust. Major biogeochemical cycles include the carbon cycle , the nitrogen cycle and the water cycle .

  5. NASA's before and after images show Earth's changing ... - AOL

    www.aol.com/news/nasas-images-show-earths...

    The Images of Change project provides side-by-side photos of the same place over time to document the ... NASA's before and after images show Earth's changing landscape. ... For example, land is ...

  6. Atmospheric chemistry - Wikipedia

    en.wikipedia.org/wiki/Atmospheric_chemistry

    Atmospheric chemistry is a branch of atmospheric science that studies the chemistry of the Earth's atmosphere and that of other planets. This multidisciplinary approach of research draws on environmental chemistry, physics, meteorology, computer modeling, oceanography, geology and volcanology, climatology and other disciplines to understand both natural and human-induced changes in atmospheric ...

  7. Geochemical cycle - Wikipedia

    en.wikipedia.org/wiki/Geochemical_cycle

    Some [who?] may use the terms biogeochemical cycle and geochemical cycle interchangeably because both cycles deal with Earth's reservoirs.However, a biogeochemical cycle refers to the chemical interactions in surface reservoirs such as the atmosphere, hydrosphere, lithosphere, and biosphere [citation needed] whereas a geochemical cycle refers to the chemical interactions that exist in crustal ...

  8. 10 Surprising Facts About Earth Day - AOL

    www.aol.com/10-surprising-facts-earth-day...

    Here are 10 interesting facts about Earth Day. Earth Day was created by a senator Gaylord Nelson, a Democratic senator from Wisconsin, was growing increasingly concerned over the state of the U.S ...

  9. Chemical cycling - Wikipedia

    en.wikipedia.org/wiki/Chemical_cycling

    Chemical cycling describes systems of repeated circulation of chemicals between other compounds, states and materials, and back to their original state, that occurs in space, and on many objects in space including the Earth. Active chemical cycling is known to occur in stars, many planets and natural satellites.